Method and apparatus for high rate packet data transmission

BACKGROUND OF THE INVENTION

I. Field of the Invention

The This invention relates to data communication. In particular, concerns , the present invention relates to a new and improved method and a device for Packet data transmission high rate.

II. Description of the Prior of the technique

On modern communications system is required to support a variety to support applications. One such communication system is a Code Division Multiple Access (CDMA) system, the "TIA / EIA / IS-95 Mobile Station-Base Station Compatibility Standard for Dual-Mode Wideband Spread Spectrum Cellular System ", hereinafter the IS-95 as the standard referred to as. The CDMA system allows voice and data communications over between users a terrestrial link. The use of CDMA techniques in a Communication system with multiple access is disclosed in US Pat. No. 4,901,307 entitled "Spread Spectrum Multiple Access Communication System Using Satellite Or Terrestrial Repeaters "and US Patent no. 5,103,459, entitled "System and Method For Generating Waveforms In A CDMA Cellular Telephone System, "both are assigned to the assignee of the present invention.

In this specification refers to the hardware base station, with mobile devices communicate. Cell refers to the hardware or the geographic Coverage area, depending of the context in which the terms are used. On Sector is a part of a cell. Because a sector of a CDMA system has the characteristics of a cell, the teachings of terms can are described from cells, be extended directly to sectors.

In the CDMA system is communication between users through a or more base stations executed. A first user of a mobile device communicates with a second user of a second mobile device by transmitting of data on the reverse link to a base station. The base station receives the data and can forward data to another base station. The data on forward link the same base station or a second base station to the second transmitted mobile device. The forward link refers to the transfer from the base station to a mobile station, and the reverse link refers to the transfer from the mobile station to a base station. In IS-95 systems, the forward link are and the reverse link assigned unteschiedliche frequencies.

the mobile device communicates during a communication with at least one base station. CDMA mobile phones are able with multiple base stations simultaneously during a Soft handoff to communicate. Soft handoff is the process of preparing a connection with a new base station before the connection will be terminated with the previous base station. minimizes soft handoff the probability of aborted talks. The method and A system for providing a communication with a mobile device via a or more base stations during the soft handoff process are disclosed in US Pat. No. 5,267,261, entitled "Mobile Assisted Soft Handoff In A CDMA Cellular Telephone System ", the owner of the of the present invention is assigned. Softer handoff is the Process, in which communication via a plurality of sectors takes place, served by the same base station. The process of Softer handoff is described in detail in co-pending U.S. Patent Application Nr. 08 / 763.498 and entitled "Method and Apparatus for Performing Handoff Between Sector Of Common Base Station ", filed on December 11, 1996, assigned to the assignee of the present invention.

Among the growing demand for wireless data applications, the need for very efficient wireless data communication systems are increasingly important become. The IS-95 standard is capable of, traffic data and Voice data via the forward and reverse links transferred to. A method for transmitting traffic data in code channel frames (code channel frames) of fixed size is described in detail in U.S. Pat. No. 5,504,773 entitled "Method And Apparatus For The Formatting Of Data For Transmission ", the owner of the of the present invention is assigned. In accordance with the IS-95 standard Traffic data or voice data is partitioned into code channel frames, <?page 3?>the 20 ms and the data rates of up to 14.4 kbps (kilobits have per second).

On significant difference between voice services and data services is the fact that the former firm and strict requirements to delay impose. Typically, the total delay must in a direction of Speech frames less than 100 ms. In contrast, the delay a variable parameter in data to be used to to optimize the efficiency of the data communication system. especially can more efficient encoding techniques are used for error correction, the much greater delays require as those that can be tolerated by voice services. On exemplary efficient coding scheme for data is disclosed in US Patent Application No. 08 / 743.688, entitled "Soft Decision Output Decoder For Decoding Convolutionally Encoded Code Words, "filed on November 6, 1996 and the holder of the present invention assigned.

On Another significant difference between voice services and data services is that the former a fixed and common service level (Grade of service, GOS) for All users require. Typically this leads for digital systems, the language services provide, at a fixed and equal transmission rate for all users and a maximum tolerated value for the error rates of the speech frames. In contrast, the GOS can for Data services by users be different from the user, and he may be parameters optimized to the overall efficiency of the data communication system to increase. The GOS of a data communication system is typically expressed as the total delay is defined, the Transfer of a predetermined amount of data, hereinafter as a data packet refers to occur.

On Yet another significant difference between data services and Voice services is that the former are a reliable communication link require, which in the exemplary CDMA communication system is provided by soft handoff. Soft handoff results in redundant transmissions of one or more base stations, the reliability to increase. However, this additional Resilience data transmission not required because the data packets received in error were transferred, again can be. For data services , the transmit power used to support soft handoff is more efficient to transfer of additional Data is used.

The Parameters, the quality of the and effectiveness a data communication system to measure the transmission delay, the transfer to is a data packet is required, and the average throughput rate of the system. Transmission delay has not have the same impact in data communication as in voice communication, but it is an important metric for measuring the quality of the data communication system. The average throughput rate is a measure of the effectiveness of capacity for data transmission the communication system.

It is well known that in cellular Systems the signal-to-noise-and-interference ratio C / I of any given user a function of the location of the user within range is. In order to maintain a given level of service, access TDMA and FDMA systems to techniques for frequency re-use back, ie not all frequency channels and / or time slots in each base station used. In a CDMA system, the same Frequency allocation reused in every cell of the system, whereby the overall efficiency is improved. The C / I that any mobile device of a user scored, determines the information rate, the specific for this compound are supported from the base station to the mobile radio device of the user can. Assuming that the specific modulation and error correction method, that for the transfer is used, and which the present invention for data transmissions optimize searches, is a given level of performance in a obtained corresponding level of C / I. For idealized cellular systems with hexagonal cell shapes and the use of a common Frequency in every cell, the distribution of C / I can be calculated, which can be achieved within the idealized cells.

Of the achieved C / I for any given user is a function of path loss, for terrestrial cellular Systems like R³ to R⁵ increased, and R is the distance to the radiation source. Furthermore, subject to the Path loss random changes because of artificial or natural Obstacles within the path of the radio wave. These random changes typically as a logarithmic shading random process modeled with a standard deviation of 8 dB. The resulting C / I distribution for an ideal hexagonal cellular Arrangement with omnidirectional base station antennas is achieved, the R⁴-Ausbreitungsgesetz And Abschattungsprozess with 8 dB standard deviation in &lt;?page 4?&gt;<figref idrefs="S95">10</figref> shown.

The obtained C / I distribution can only be achieved if, in every Moment and in any place the mobile device by the best base station is operated, which is defined as that having the highest C / I-value obtained independently of the physical distance to each base station. by virtue of the random nature the path loss as described above, the signal with the highest C / I-value may be a signal which is not the minimum physical distance of the mobile radio device having. Much more, the C / I can be substantially degraded, when a mobile station only over could communicate with the base station with the minimum distance. It therefore for cellular devices useful, to communicate at all times with the best serving base station, whereby the optimum C / I value is obtained. It can also be observed that the range of values ​​of C / I achieved in the above idealized Model and as in <figref idrefs="S95">10</figref> one such is shown, that the difference between the highest and lowest Values ​​can be up to 10,000. In practical implementations the range is typically about 1: limited 100 or 20 dB. It is therefore for a CDMA base station is possible, cellular devices to operate with information bit rates up to a factor of 100 may vary, because the following relation holds: <img img-content="mf" img-format="tif" he="15" wi="126" file="00060001.tif" />

there represents R_b the information rate to a certain mobile device represents, W is the total bandwidth by the spread spectrum signal is occupied, and E_b/ I₀ the Energy per bit over the interference density that is required to a given level of performance to achieve. If z. B. the spread spectrum signal bandwidth W occupied by 1.2288 MHz and reliable communication an average e_b/ I₀ = 3 dB requires, then a mobile radio device, which achieves a C / I value of 3 dB to the best base station with a data rate of up to 1.2288 Mbps (megabits per second) communicate. On the other hand, if a mobile device integral interference subject of neighboring base stations and only achieve a C / I of -7 dB can, then can reliable Communications greater at a rate as unsupported 122.88 Kbps will. A communication system for optimizing the average Throughput was designed, therefore try to avoid any remote User from the best serving base station and at the highest data rate R_b to provide that the remote user reliable can support. The data communication system of the present invention utilizes the presented above characteristics and optimizes the data throughput CDMA base stations to mobile devices.

It Attention is drawn to the document WO 96/10320, the data transmission method a disclosed in a TDMA mobile communication system. In a mobile communication system, the a so-called multi-slot access technique applies to one or more time slots to a mobile station for data transmission with the data transfer rate be assigned, which are required by an application , mobile station uses. After establishing a data connection, the mobile device is the mobile communication network the minimum and maximum requirements for the transmission rate of user data to (build, setup). The mobile communication network assigns the mobile station for a data connection a channel configuration, depending on the network resources, the currently available are provided, and the mobile communication network, and enables Data transfer rate between the minimum requirement and the maximum requirements lies.

It is also drawn to the document US-A-5,093,924, the general one Assigning method for use in mobile communication systems, disclosed, wherein a base station in response to a communication link request a communication radio channel selects which an interference wave reception level which is obtained by a measuring unit, and a quality condition a communication channel from a plurality of communication radio channels meet, and Information of the communication radio channel to a mobile radio device as a transmits object of the communication connection request. The mobile unit selects the Communication radio channel transmitted from the base station is, measures an interference wave reception level and transmits the measurement result to the base station. The base station checks whether the measurement result of the quality conditions fulfills a communication path and assigns the communication radio channel to the requested communication to when the measurement result, the quality conditions of the communication path fulfilled.

furthermore Attention is drawn to the document US-A-5,442,625, that a multi-code division multiple access system disclosed that it allows a user at a radio transmission unit its source data bit rates dynamically change. The plurality of source bit rates comprises a base-bit rate, and &lt;?page 5?&gt;at least one bit rate which a Multiple of the basic bit rate. The user's input selects a particular source bit rate of the user from using a multiple a basic bit rate of a base station is informed that the transmission receives.

In accordance with the present invention, a method for packet data transmission with high speed as set forth in claim 1, and an apparatus for packet data transmission at high speed, as set out in claims 49 and 54, are provided. embodiments of the invention are in the dependent claims described.

SUMMARY THE INVENTION

The This invention is a novel and improved method and a device for Packet data transmission at a high rate in a CDMA system. the present invention improves the efficiency of a CDMA system by Be provision of funds to transfer of over data the forward and reverse links. Each mobile device communicates with one or more base stations and monitors the control channels for the Duration of the communication with the base stations. The Kontrolkanäle can of the base stations are used to small amounts of data, Paging (paging) messages addressed to a specific mobile station are, and to transmit collective messages to all mobile devices. The paging message informs the mobile device, that the base station a large Amount of data for transmission to mobile station present.

It An object of the present invention, the use of forward and Reverse link capacity in the to improve data communication system. Upon receipt of the paging messages of one or more base stations, mobile station measures the signal-to-noise-and-interference ratio (C / I) the forward link signals (Z. B. the pilot signals of the forward link) in each time slot and selects the best base station using a set of parameters from, which can comprise the present and previous C / I measurements. In one embodiment, the mobile device transmits in each Time slot to the selected Base station a specific data request channel (DataRequest Channel, DRC) a Request for transfer with the highest Data rate that can support the measured C / I reliable. The selected Base station transmits data in data packets with a data rate, the data rate of the one of the mobile radio device was received, does not exceed, on the DRC channel. Beaming from the best base station in each time slot to be improved achieved throughput and improved transmission delay.

It is a further object of the present invention, the power to improve by transfer from the selected Base station with the highest Transmit power for the duration of one or more time slots to a mobile device with the Data rate that has been requested by mobile station. In the exemplary CDMA communication system, the base station uses a predetermined Security (back-off) (z. B. 3 dB) of the available transmit power to change be considered in the application. Therefore, the average transmit power is half of the highest Power. However, since in the present invention, data transmissions be scheduled at a high speed and performance typically is not shared (z. B. between transmissions), it is not necessary for the available highest Transmit power to account for security.

It is yet another object of the present invention, the efficiency of to improve, by the base stations is allowed, data packet to any mobile device via a variable number of time slots to be transmitted. The possibility, from time slot to time slot from different base stations transferred to, allows the data communication system of the present invention, adapt quickly to changes adjust in the operating environment. In addition, in the present Invention possible a data packet over non-contiguous time slots transferred to, due to the use of sequence numbers (sequence numbers) to identify the data units within a data packet.

It is a still further object of the present invention to increase flexibility by the data packets that are addressed to a specific mobile station must be forwarded from a central controller to all base stations, the elements of the active set of the mobile device is. In the present Invention is data transmission from each base station in the active set of the mobile device in any Time slot possible. Since each base station comprises a queue which the to be transmitted to mobile station contains data, is efficient forward link transmission with minimal processing delay possible.

It is a still further object of the present invention to provide a mechanism for retransmission &lt;?page 6?&gt;from provide data units received in error. In the exemplary embodiment, each data packet a predetermined number of data units, in of each data unit by a serial number (sequence number) is identified. After the incorrect reception of one or a plurality of data units sends the mobile device a negative acknowledgment (negative acknowledgment, NACK) on the reverse link data channel, of the serial numbers of the missing data units for retransmission indicative of the base station. The base station receives the NACK message and can transmit the erroneously received data units again.

It is a still further object of the present invention for the mobile station the best candidates for select base stations for communication, based on the method, which is described in US patent application no. 08 / 790.497 and which is entitled "Method And Apparatus For Performing soft handoff In A Wireless Communication System "filed, January 29, 1997 and assigned to the assignee of the present invention. In one embodiment, the base station can be added to the active set of the mobile device, if the received pilot signal over a predetermined addition removal order wave is, and it is from the Active Set removed when the predetermined pilot signal under a Entfernschwelle located. In an alternative embodiment can be added to the active set the base station, the extra Power of the base station (eg. As such by the pilot signal measured) and the energy of the base stations to the active set already belong, exceed a predetermined threshold. When using this alternative embodiment, a base station, whose transmitted Energy received an insignificant amount of the total at the mobile station includes energy, not added to the Active Set.

It is a still further object of the present invention for the mobile devices, which Data rate requests on the DRC channel in a manner such transferred to, that only the selected Base station among the base stations in Kom communication with the mobile device in the Is able to detect the DRC messages, which ensures is that the transmission on forward link takes place in any given time slot of the selected base station. In the exemplary embodiment, each base station is a unique mobile station in communication with the Walsh code assigned. The mobile station encodes (covers) the DRC message with the Walsh code corresponding to the selected base station. Other codes be used to encode the DRC messages, although orthogonal codes are typically utilized and Walsh codes are preferred.

SHORT DESCRIPTION THE DRAWINGS

The Features, objects and advantages of the present invention are prepared from the detailed description hereinafter more fully understood, when taken together with the drawings in which like reference characters identify correspondingly throughout and wherein:

<figref idrefs="S81">1</figref> is a diagram of a data communication system of the present invention, a plurality of cells, a plurality of base stations, and a plurality of mobile devices includes;

<figref idrefs="S82">2</figref> is an exemplary block diagram of the subsystems of the data communication system the present invention;

<figref idrefs="S83">3A</figref> - <figref idrefs="S85">3B</figref> are Block diagrams of the exemplary forward link architecture of present invention;

<figref idrefs="S84">4A</figref> is a diagram of the exemplary forward link frame structure of the present invention;

<figref idrefs="S86">4B</figref> - <figref idrefs="S86">4C</figref> are Diagrams of the exemplary forward traffic channel and power control channel;

<figref idrefs="S87">4D</figref> is a diagram of the punctured packet of the present invention;

<figref idrefs="S88">4E</figref> - <figref idrefs="S88">4G</figref> are Diagrams of two exemplary data packet formats and the Steuerkanalkapselung;

<figref idrefs="S89">5</figref> is an exemplary timing diagram of the packet transmission at a high rate the forward link shows;

&lt;?page 7?&gt;

<figref idrefs="S90">6</figref> is a block diagram of the exemplary reverse link architecture of the present invention;

<figref>7</figref> is a diagram of the exemplary Reverse link frame structure of the present invention;

<figref idrefs="S92">7B</figref> is a diagram of the exemplary reverse Windwärts link access channel;

<figref idrefs="S93">8</figref> is an exemplary timing diagram for data transfer at a high rate the reverse link shows;

<figref idrefs="S94">9</figref> is an exemplary state diagram showing the transitions between the various operating conditions of the mobile shows; and

<figref idrefs="S95">10</figref> is a diagram of the cumulative distribution function (cumulative distribution function, CDF) of the C / I distribution in an ideal hexagonal cellular layout.

DETAILED DESCRIPTION OF THE INVENTION

In accordance with the exemplary embodiment, takes place of the data communication system of the present invention data transmission on forward link from a base station to a mobile station (see <figref idrefs="S81">1</figref>) at or near the maximum data rate that the forward link and the system supports can be. Data communication on the reverse link is performed by a mobile device to a or more base stations. The calculation of the maximum data rate for transfers on forward link is described in detail below. Data is divided into data packets, wherein each data packet over one or more time slots (or slots) is transmitted. In each time slot, the base station the data transmission to each mobile station judge, which is in communication with the base station.

Initially provides , mobile station a communication with a base station using a predetermined access procedure ago. In this connected state , mobile station receive data and control messages from the base station and is capable of data and control messages to the base station transferred to. monitors Mobile station the forward link on transfers from the base stations in the active set of the mobile device. the Active Set contains a list of base stations which are in communication with the mobile device. In particular, the mobile station measures the signal-to-noise and Interference ratio (C / I) of the pilots of the forward link from the base stations in the active set, as received by the mobile radio device has been. If the received pilot signal is above a predetermined add threshold or is below a predetermined Entfernschwelle reported , mobile station this to the base station. Subsequent messages from the base station instruct the mobile station to which base station (s) add to its Active Set or to remove. The various operating states of the mobile device described below.

If there are no data to send, the mobile station returns to a Idle state and interrupts the transmission the data rate information to the base station (s). While the mobile device is in the idle state, the mobile station monitors the control channel of one or more base stations in the active set for paging messages (Paging messages).

If Data are available to be transmitted to the mobile device, the Data through a central controller to all base stations in sent to the Active Set and in a queue at each base station stored. A paging message is then passed through one or more Base stations sent to the mobile station on the respective control channels. The base station can all such paging messages at the same time over transfer multiple base stations, a reception ensure, even if the mobile communications device between Base stations changes. demodulated and decoded, mobile station the signals on one or more control channels to the paging messages to recieve.

After decoding the paging messages, and for each time slot until the data transmission is completed, the mobile station measures the C / I of forward link signals from the base stations in the active set, as received by the mobile radio device has been. The C / I of the forward link signals can are obtained by measuring the respective pilot signals. The mobile device then selects the best base station based on a set of parameters from. The set of parameters can be instantaneous and,&lt;?page 8?&gt;a stale C / I measurements and the Bit error rate or the packet error rate include. For example, the best base station can be selected based on the highest C / I measurement. Mobile station then identifies the best base station and transmits to the selected base station a data request message (data request message) (hereinafter as the DRC message hereinafter) on the Datenanfor ation canal (Data request channel) (hereinafter referred to as the DRC channel hereinafter). The DRC message, the requested data rate or, alternatively, an indication of the quality the forward link channel (Z. B. the C / I measurement itself, the bit error rate or the packet error rate) contain. In the exemplary embodiment, mobile station, the transmission align the DRC message to a specific base station by Using a Walsh code that uniquely identifies the base station. On the symbols of the DRC message is an exclusive-or (XOR) with the unique Walsh code applied. Since each base station in the Active Set of the mobile device is identified by a unique Walsh code, can only the selected Base station which the identical XOR operation with the correct performs Walsh code, the by mobile station accomplished was, decode the DRC message correctly. The base station uses the Rate control information from each mobile station to forward link data with the highest potential Rate to transmit efficiently.

In each time slot, the base station each of the called (paged) cellular devices for data transmission choose. The base station then determines the data rate at which the data transmitted to the selected mobile station are based on the most recent value of the DRC message received from the mobile radio device was received. additionally identifies the base station clearly a transmission to a particular mobile device using a spreading code (spreading code) that is unique for the mobile station is. In the exemplary embodiment, is this spreading of Long Pseudo Noise (PN) code that is defined the IS-95 standard.

the Mobile device, for the the data packet is intended, receives data transfer and decodes the data packet. Each data packet comprises a plurality of data units. In the exemplary embodiment, a data unit 8 information, although different sizes of the data unit defined can be and gene within the scope of the present invention lie. In the exemplary embodiment, each data unit includes a sequence number (sequence number) assigned, and the mobile devices are able, either missing or duplicate transmissions to identify. In such cases communicate the mobile devices via the Data channel of the reverse link the serial numbers of the missing data units. The base station controller, which receive the data messages from the mobile devices, then give all Base stations communicating with this particular mobile station, what data units were not received by the mobile device. The Base stations then schedule a retransmission of such data units.

Each mobile device in the data communication system can communicate with several base stations on the reverse link communicate. In the exemplary embodiment supports The data communication system of the present invention soft handoff and softer handoff on the reverse link for many reasons. First, consume soft handoff no additional capacity on the Reverse link, but also allows the mobile devices, to transmit data at the minimum power level such that at least one of the base stations can decode the data reliably. Secondly, elevated a reception of the reverse link signals through multiple base stations, the reliability of the transmission and only requires additional Hardware in the base stations.

In the exemplary embodiment, is the forward link capacity of the data transmission system the present invention by the rate requests of the mobile device determined. additional increases the forward link capacity can Using directional antennas and / or adaptive spatial Filtering can be achieved. An exemplary method and apparatus for providing directional transmissions are disclosed in co-pending US patent application Ser. No. 08 / 575.049, entitled "Method And Apparatus For Determining The Transmission Data Rate In A Multi-User Communication System "filed, On 20 December 1995, and US patent application Ser. No. 08 / 925.521 with the title "Method And Apparatus For Providing Orthogonal spotbeams, Sectors And picocells ", filed on September 8, 1997, both the owner of the present application assigned.

I. System Description

With , reference to the figures <figref idrefs="S81">1</figref> the exemplary The data communication system of the present invention is that several cell <figref>2a</figref> - <figref>2g</figref> includes. Each cell <figref>2</figref> is a corresponding base station <figref>4</figref> provided. Various mobile devices <figref>6</figref> are distributed within the data communication system. In&lt;?page 9?&gt;of exemplary embodiment communicates each of the mobile devices <figref>6</figref> with more than a base station <figref>4</figref> on the forward link at each time slot, but can be in communication with one or more base stations <figref>4</figref> on the reverse link are dependent whether the mobile station <figref>6</figref> themselves is in soft handoff. For example, the base station<figref>4a</figref> data exclusively to mobile station <figref>6a</figref>. the base station <figref>4b</figref> transmits data exclusively to mobile station <figref>6b</figref>. and base station <figref>4c</figref> transmits data exclusively to , mobile station <figref>6c</figref> on the forward link n in the time slot. In <figref idrefs="S81">1</figref> , the solid line with the arrow data transmission from the base station <figref>4</figref> to mobile station <figref>6</figref> at. A broken line with the arrow indicates that mobile station <figref>6</figref> the Pilot signal, but no data transmission, from the base station <figref>4</figref> receives. The communication on the reverse link is the simplicity in <figref idrefs="S81">1</figref> not shown.

As in <figref idrefs="S81">1</figref> shown, transmits each base station <figref>4</figref> preferably at any given moment Data to a mobile station <figref>6</figref>, cellular devices <figref>6</figref>. especially those located near a cell boundary, can Pilot signals from multiple base stations <figref>4</figref> receive. If the pilot signal over a predetermined threshold, the mobile station may <figref>6</figref> promote, that the base station <figref>4</figref> to the active set of the mobile device <figref>6</figref> will be added. In the exemplary embodiment, , mobile station <figref>6</figref> data transmission by zero or received a member of the Active Set.

On Block diagram illustrating the basic subsystems of the data communication system of the present invention, is in <figref idrefs="S82">2</figref> shown. The base station controller <figref>10</figref> is with the packet network interface <figref>24</figref>, The PSTN <figref>30</figref>. and all base stations <figref>4</figref> in the data communication system connected (only one base station is in <figref idrefs="S82">2</figref> the simplicity shown for simplicity). The base station controller<figref>10</figref> coordinated the communication between mobile devices <figref>6</figref> in the data communication system and other users that the packet network interface <figref>24</figref> and the PSTN <figref>30</figref> connected are. The PSTN<figref>30</figref> with users through the standard telephone network (in <figref idrefs="S82">2</figref> not shown).

Of the Base station controller <figref>10</figref> contains many selector elements <figref>14</figref>. although for simplicity in <figref idrefs="S82">2</figref> only one is shown. one selector element<figref>14</figref> is the control of the Communication between one or more base stations <figref>4</figref> and a mobile radio device <figref>6</figref> assigned. If the selector element <figref>14</figref> not the mobile device <figref>6</figref> assigned is, the connection control processor <figref>16</figref> (Call control informs processor) of the necessity of the mobile station <figref>6</figref> to call. The connection control processor<figref>16</figref> then has the base station <figref>4</figref> on, the mobile station <figref>6</figref> to call.

A Data Source <figref>20</figref> contains the data to mobile station <figref>6</figref> transferred to are. The data source<figref>20</figref> provides the data to packet network interface <figref>24</figref> ready. The packet network interface <figref>24</figref> receives the data and forwards the data to selector element <figref>14</figref> continue. the selector element <figref>14</figref> sends the data to each base station <figref>4</figref>. in communication with the mobile station <figref>6</figref> stands. Each base station<figref>4</figref> maintains a data queue <figref>40</figref>That contains the data that to mobile station <figref>6</figref> transferred to are.

In the exemplary embodiment, on the forward link, refers to a data packet to a predetermined amount of data, the independent is of the data rate. The data packet is, and with other tax Coding bits formatted and encoded. If data transmission occurs over multiple Walsh channels, will the encoded packet in parallel streams unbundled (demultiplexed), wherein any power over transmitted a Walsh channel is.

The Data in data packets from data queue <figref>40</figref> at a channel member <figref>42</figref> Posted. For each data packet, channel element adds<figref>42</figref> the necessary control fields. The data packet, control fields, Frame Check Sequence bits and code tail bits comprise a formatted Package. The channel member<figref>42</figref> then encodes one or more formatted packets and interleaves (interleaves) the symbols (or reorders) within the encoded packet. Then, the interleaved Package with an encryption sequence encrypted with Walsh codes encoded and with the long PN code and the short PN_I- and PN_QCodes spread. The spread data be by a transmitter within RF unit <figref>44</figref> quadrature-modulated, filtered and amplified. The forward link signal is over an antenna <figref>46</figref> through the air over the forward link <figref>50</figref> transfer.

at the mobile radio device <figref>6</figref> becomes the forward link signal through an antenna <figref>60</figref> received and to a receiver a Front End <figref>62</figref> forwarded. The receiver filters, strengthened quadrature demodulates, and quantizes the signal. The digitized Signal is a demodulator (DEMOD) <figref>64</figref> provided where it with the long PN code and the short PN_I- and PN_QCodes despread with the Walsh codes is decoded and decrypted with the identical encryption sequence. The demodulated data &lt;?page 10?&gt;a decoder <figref>66</figref> provided, performs the inverse of the signal processing functions to the base station <figref>4</figref> were carried out, in particular de-interleaving, Decoding and frame check functions. The decoded data is provided to a data sink <figref>68</figref> provided. The hardware, as described above, supports transmissions of data, messaging, Voice, video and other communications over the forward link.

The Functions for system control and time planning can many implementations can be achieved. The location of channel scheduler<figref>48</figref> (channel Scheduler) depends on whether a centralized or distributed control / scheduling processing required is. For example for distributed processing, channel scheduler can <figref>48</figref> within each base station <figref>4</figref> be arranged. Conversely, for centralized Processing, the channel planner can <figref>48</figref> within the base station controller <figref>10</figref> arranged and be designed to the data transmissions of multiple base stations <figref>4</figref> to coordinate. Other implementations of the functions described above can are contemplated and are within the scope of present invention.

As in <figref idrefs="S81">1</figref> shown, the mobile stations are <figref>6</figref> within distributes the data communication system and can use the forward link in communication with zero or one base station <figref>4</figref> to stand. In the exemplary embodiment, coordinated the channel planner <figref>48</figref> data transfers over the forward links a base station <figref>4</figref>, In the exemplary embodiment, connects the channel planner <figref>48</figref> with the data queue <figref>40</figref> and the channel member <figref>42</figref> within the base station <figref>4</figref> and receives the queue size, the the amount of the to mobile station <figref>6</figref> to be transmitted Data indicates and the DRC messages from mobile devices <figref>6</figref>, The channel scheduler <figref>48</figref> planning data transmission at a high rate, so that the system goals of maximum data throughput and minimum transmission delay are optimized.

In the exemplary embodiment, is the data transmission based in part on the quality of the communication link planned. A beispielhaf tes communication system transmission rate, based on the connection quality, selects, is disclosed in US patent application Ser. No. 08 / 741.320, entitled "METHOD AND APPARATUS FOR PROVIDING HIGH SPEED DATA COMMUNICATIONS IN A CELLULAR ENVIRONMENT "filed on September 11, 1996 and the holder of the present invention assigned. In the present invention, the scheduling of the data communication on additional considerations based, such as the GOS of the user, the queue size, the type the data, the size of the already delay occurred and the error rate of data transmission. These considerations are described in detail in US patent application Ser. No. 08 / 798.951 with the Title: "METHOD AND APPARATUS FOR FORWARD LINK RATE SCHEDULING ", filed February 11, 1997 and the US patent application with a serial number and entitled: "METHOD AND APPARATUS FOR REVERSE LINK RATE SCHEDULING ", filed on 20 August 1997, both assigned to the assignee of the present invention. Other factors can wherein the scheduling of data transmissions be considered and are within the scope of the present invention.

the The data communication system of the present invention supports data and message transmissions on the reverse link. Within the mobile device <figref>6</figref> processed the controller <figref>76</figref> the data or message transmission by forwarding the data or message to an encoder <figref>72</figref>, Of the controller <figref>76</figref> can by a microcontroller, a microprocessor, implements a digital signal processing chip (DSP) or an ASIC be, of the implementation the functions described here is programmed.

In the exemplary embodiment, encodes the encoder <figref>72</figref> the message according to the blank-and-burst signaling data format, which is described in the aforementioned US Pat. No. 5,504,773. The encoder <figref>72</figref> then generates a set of CRC bits and hangs them to depend, a set of code tail bits, encodes the data and appended bits and arranges the icons within the encoded data. The interleaved Data to modulator (MOD) <figref>74</figref> provided.

Of the modulator <figref>74</figref> can be implemented in many embodiments will. In the exemplary embodiment (see<figref idrefs="S90">6</figref>) the interleaved data with Walsh codes to be coded, with a spread long PN code, and further spread with the short PN codes. The spread data is provided to a transmitter within the front-end <figref>62</figref> provided. The transmitter modulates, filters, and amplifies and transmits the reverse link signal over the antenna <figref>46</figref> through the air on the reverse link <figref>52</figref>,

In the exemplary embodiment, spreads the mobile station <figref>6</figref> the Reverse link data &lt;?page 11?&gt;in accordance with a long PN code. Each reverse link channel is in accordance with the temporal offset of a common long PN sequence defined. At two different offsets are not correlated, the resulting modulation sequences. Of the Offset of a mobile telephone <figref>6</figref> becomes in accordance with a unique numerical identification of the mobile device <figref>6</figref> determines what in the exemplary embodiment, of the IS-95 mobile radio device <figref>6</figref> the specific identification number of the mobile device is. Therefore, each mobile station transmits <figref>6</figref> on an uncorrelated Reverse link channel, prepared in accordance was determined with its unique electronic serial number.

at the base station <figref>4</figref> is the reverse link signal by the antenna <figref>46</figref> receive and the RF unit <figref>44</figref> provided. The RF unit <figref>44</figref> filters, amplifies, demodulates, and quantizes the signal and provides the digitized signal to channel element <figref>42</figref> ready. The channel member <figref>42</figref> despreads the digitized signal with the short PN codes and the long PN code. The channel member<figref>42</figref> also leads the decoding of the Walsh codes and the extraction of the pilot and DRC through. The channel member<figref>42</figref> then arranges the demodulated Data to, encoding the de-interleaved data, and performs the CRC check function out. The decoded data, for example. The data or message, is the selector element <figref>14</figref> provided. The selector element<figref>14</figref> passes the data and the message to the right goals. The channel member<figref>42</figref> can also a quality indicator to the selector element <figref>14</figref> forward, the state the the received data packet indicates.

In the exemplary embodiment, , mobile station <figref>6</figref> in one of three operating states. An exemplary state diagram showing the transitions between the various operating conditions of the mobile <figref>6</figref> shows, is in <figref idrefs="S94">9</figref> shown. In the access state<figref>902</figref> sends , mobile station <figref>6</figref> access signals (Access coarse) and waits for channel assignment by base station <figref>4</figref>, The channel assignment comprises allocation of resources, such as a Power control channel and frequency allocation. Mobile station<figref>6</figref> can of the access condition <figref>902</figref> in the connected state <figref>904</figref> pass, when the mobile device <figref>6</figref> called (Paged) and is drawn to upcoming data transmission, or when the mobile device <figref>6</figref> data transmits on the reverse link. In the connected state <figref>904</figref> exchanges, mobile station <figref>6</figref> data (Sends z. B. or receives) from and leads Handoff operations. After a dismissal procedure, the mobile station goes <figref>6</figref> from the connected state <figref>904</figref> in the idle state <figref>906</figref> about. the mobile device <figref>6</figref> can also from the access state <figref>902</figref> in the idle state <figref>906</figref> pass, after a connection with the base station <figref>4</figref> rejected has been. In the idle state<figref>906</figref> respects the mobile device <figref>6</figref> on Overhead and paging messages by messages on the forward control channel receives (Forward Control Channel) and decoded and the idle handoff procedure performs. Mobile station <figref>6</figref> can in the access state <figref>902</figref> arrive by initiating the procedure. This in <figref idrefs="S94">9</figref> State diagram shown is merely an exemplary State definition which is shown for illustrative purposes. Other State diagrams can also be used and are within the scope of the present Invention.

II. Data transmission via the forward link

In the exemplary embodiment, happens initiating a communication between the mobile radio device <figref>6</figref> and the base station <figref>4</figref> in a similar manner as for the CDMA system. After the completion of the connection setup to monitor the mobile device <figref>6</figref> the Control channel for paging messages. While it is connected in the State, the mobile station begins <figref>6</figref> the transfer of the pilot signal on the reverse link.

On exemplary flow diagram of the data transmission at a high rate at the forward link of the present invention is in <figref idrefs="S89">5</figref> shown. If the base station <figref>4</figref> Data to transmit to mobile station <figref>6</figref> present, the base station transmits <figref>4</figref> a paging message addressed to , mobile station <figref>6</figref> addressed is, on the control channel at block <figref>502</figref>, The paging message can be from one or more base stations <figref>4</figref> Posted are, depending of the handoff state of the mobile <figref>6</figref>, After receiving the paging message, mobile station begins <figref>6</figref> the C / I measurement process at block <figref>504</figref>, The C / I of the forward link signal is described from one or a combination below Method calculates. Mobile station<figref>6</figref> then selects a requested data rate based on the best C / I measurement, and transmits a DRC message on the DRC channel at block <figref>506</figref>,

Within receives the same time slot the base station <figref>4</figref> the DRC message at block <figref>508</figref>, If the next For time slot data transmission available is, the base station transmits <figref>4</figref> data to the mobile device <figref>6</figref> With the requested data rate at block <figref>510</figref>, Mobile station<figref>6</figref> receives the data transmission at block <figref>512</figref>, If the next time slot is available, transmits the base station<figref>4</figref> the Rest of the Pa&lt;?page 12?&gt;kets at block <figref>514</figref>And mobile station <figref>6</figref> receives the data transmission at block <figref>516</figref>,

In of the present invention, mobile station <figref>6</figref> at the same time with one or more base stations <figref>4</figref> communicate. The measures of the mobile radio device <figref>6</figref> moved will depend on whether the mobile station <figref>6</figref> themselves is in soft handoff or not. These two cases discussed separately below.

III. The case of the non-handoff

If no handoff is present, communicates the mobile device <figref>6</figref> With a base station <figref>4</figref>, Regarding<figref idrefs="S82">2</figref> will the data for a particular mobile device <figref>6</figref> certainly are, the selector element <figref>14</figref> provided, which control the communicating with this mobile device <figref>6</figref> is assigned. The selector element <figref>14</figref> forwards the data to the data queue <figref>40</figref> within the base station <figref>4</figref> continue. The base station<figref>4</figref> lined up transmits the data a and a Paging message on the control channel. The base station<figref>4</figref> then monitored the DRC channel of the reverse link to DRC messages from the mobile device <figref>6</figref>, If on the DRC channel no signal is detected, the base station <figref>4</figref> the transmitted paging message until the DRC message is detected. After a predetermined number can of attempts retransmission the base station <figref>4</figref> end the process or a connection with the mobile station <figref>6</figref> again start.

In the exemplary embodiment, the mobile station transmits <figref>6</figref> the requested data rate in the form of a DRC message to the base station <figref>4</figref> on the DRC channel. In the alternative embodiment, mobile station transmits<figref>6</figref> a Indication of the quality the forward link channel (for example, the C / I measurement) to base station<figref>4</figref>, In the exemplary embodiment, is the 3-bit DRC message with soft decisions (decisions drank) by the base station <figref>4</figref> decoded. In the exemplary embodiment is transmitted within the first half of each time slot, the DRC message.

Of the base station <figref>4</figref> then is the remaining half of the Time slot to decode the DRC message and configure the hardware for data transmission in the next following time slot available, if the time slot for data transmission to mobile station <figref>6</figref> to disposal stands. If the next following timeslot unavailable is waiting for the base station <figref>4</figref> on the next available time slot and drives continues to monitor the DRC channel to the new DRC messages.

In of the first embodiment the base station transmits <figref>4</figref> at the requested data rate. This embodiment leaves the mobile device <figref>6</figref> the important decision of selecting the data rate. Always send the requested data rate, has the advantage that mobile station <figref>6</figref> knows what Data rate is expected to deliver. Then modulates and decodes the mobile device <figref>6</figref> just the traffic channel in accordance at the requested data rate. The base station<figref>4</figref> have to be no message to mobile station <figref>6</figref> transfer, indicating which data rate by the base station <figref>4</figref> used is.

In the first embodiment, after receiving the paging message, mobile station tries the <figref>6</figref> continuous to demodulate the data at the requested data rate. Mobile station<figref>6</figref> demodulates the forward traffic channel and provides the soft decision symbols to the decoder ready. The decoder decodes the symbols and performs the frame check on the decoded packet in order to determine whether the packet correctly was received. If the packet was received in error or if the packet to another mobile device <figref>6</figref> was directed, would the Frame review a specify packet error. Alternatively, in the first embodiment, demodulates the mobile station <figref>6</figref> the Data on a slot-by-slot basis. In the exemplary embodiment, is the mobile station <figref>6</figref> in determine the location, whether a data transmission to this mobile device itself is directed, based on a preamble, transmitted in each contained data packet, as described below. Therefore, the mobile device <figref>6</figref> the terminate decoding process, if it is determined that the transmission to another mobile device <figref>6</figref> directional is. In any case, the mobile station transmits<figref>6</figref> a negative acknowledgment message (Negative acknowledgments message, NACK) to the base station <figref>4</figref>. to confirm the incorrect reception of the data units. After this Receiving the NACK message, the data units received in error retransmitted.

The transfer the NACK messages can be implemented in a manner which the transfer the error indicator bits (error indicator bit, EIB) is similar to the CDMA system. The implementation and use of EIB transmission are disclosed in US Pat. No. 5,568,483, entitled "METHOD AND APPARATUS FOR THE FORMATTING OF DATA FOR TRANSMISSION ", the owner of the of the present invention is assigned. Alternatively, NACK transmitted messages will.

&lt;?page 13?&gt;

In of the second embodiment is the data rate by the base station <figref>4</figref> owing to Data (Input) of the mobile radio device <figref>6</figref> certainly. the mobile device <figref>6</figref> leads the C / I measurement and transmits a Note on the link quality (eg. As the C / I measurement) the base station <figref>4</figref>, The base station<figref>4</figref> can the requested data rate based on the at the base station <figref>4</figref> available resources, adapt such. as the size of the queue and the available Transmission power. The adjusted data rate can to mobile station<figref>6</figref> in front or simultaneously with data transmission matched with the transmitted data rate , or they may be implicit in the encoding of the data packets be included. In the first case where the mobile station<figref>6</figref> the adjusted data rate before the data transmission receives, demodulates and decoded, mobile station <figref>6</figref> the received packet in the manner described in the first embodiment. In the second case where the adjusted data rate to mobile station <figref>6</figref> simultaneously transmitted with the data transmission is, the mobile station may <figref>6</figref> the Forward Traffic Channel demodulate and store the demodulated data. After receiving the adjusted data rate, mobile station decodes <figref>6</figref> the data in accordance with the adjusted data rate. And in the third case, wherein the contain customized data rate implicit in the coded data packages is demodulated and decoded, mobile station <figref>6</figref> all sorts Rates and determined in retrospect, the transmission rate to choose the decoded data. The method and apparatus for performing Rate determination are described in detail in US Patent Application Ser. No. 08 / 730.863, entitled "METHOD AND APPARATUS FOR DETERMINING THE RATE OF RECEIVED DATA IN A VARIABLE RATE COMMUNICATION SYSTEM " filed on 18 October 1996 and the patent application Nr. PA436, which also bears the title "METHOD AND APPARATUS FOR DETERMINING THE RATE OF RECEIVED DATA IN A VARIABLE RATE COMMUNICATION SYSTEM " filed, and both the owner of the present Sign assigned. In all cases described above, mobile station transmits<figref>6</figref> a NACK message as described above if the outcome of the frame check is negative is.

The The following discussion is based on the first embodiment wherein mobile station <figref>6</figref> the base station <figref>4</figref> transmits the DRC message, the requested data rate indicating except if it is indicated otherwise. However, the herein described inventive concept is also applicable to the second embodiment, in which , mobile station <figref>6</figref> a Indication of the link quality to the base station <figref>4</figref> transfers.

IV. The case of handoffs

in the Case handoff communicates the mobile device <figref>6</figref> with multiple base stations <figref>4</figref> on the reverse link. In the exemplary embodiment, takes place on the data transmission forward link to a particular mobile station <figref>6</figref> from a base station <figref>4</figref> out. However, mobile station<figref>6</figref> simultaneously the pilot signals from multiple base stations <figref>4</figref> receive. If the C / I measurement of a base station <figref>4</figref> over a predetermined threshold, the base station is <figref>4</figref> the Active Set of the mobile device <figref>6</figref> added. During the Soft handoff direction message, the new base station <figref>4</figref> the mobile device <figref>6</figref> a Reverse power control (RPC) Walsh channel which described below is. Each base station<figref>4</figref>Which is in soft handoff with the mobile radio device <figref>6</figref> is monitored the transfer on the reverse link and sends an RPC bit on their respective RPC Walsh channels.

With in reference to <figref idrefs="S82">2</figref> directs the selector element <figref>14</figref>. the control of the communication with the mobile station <figref>6</figref> assigned is, the data to all base stations <figref>4</figref> in the active set of the mobile <figref>6</figref> continue. All base stations <figref>4</figref>, The data from the selector element <figref>14</figref> received, transferred a paging message to mobile station <figref>6</figref> on their respective control channels. When the mobile station <figref>6</figref> in the connected state, leads , mobile station <figref>6</figref> two Functions. First select , mobile station <figref>6</figref> the best base station <figref>4</figref> made, based on a set of Parameters, which can be the best C / I measurement. Mobile station<figref>6</figref> then selects a data rate corresponding to the C / I measurement and transmits a DRC message to the selected base station <figref>4</figref>, Mobile station<figref>6</figref> may transfer of the DRC message to a specific base station <figref>4</figref> judge, by encoding the DRC message with the Walsh code (Walsh Cover) (Covers) of the respective base station <figref>4</figref> assigned is. Second, the mobile device attempts<figref>6</figref> the forward link signal in accordance with the requested data rate in each successive time slot to demodulate.

After transferring monitor the paging messages all base stations <figref>4</figref> in the active set the DRC channel on a DRC message from the mobile device <figref>6</figref>, Since the DRC message is encoded with a Walsh code, the selected base station <figref>4</figref>. assigned to the identical Walsh code, in turn, capable of to decode the DRC message. Upon receipt of the DRC message, the selected base station transmits<figref>4</figref> data to mobile station <figref>6</figref> in the next available Time slots.

&lt;?page 14?&gt;

In the exemplary embodiment, the base station <figref>4</figref> data in packets having a plurality of data units, with the requested data rate to mobile station <figref>6</figref>, If the data units by mobile station <figref>6</figref> not correct is received, a NACK message on the reverse links to all base stations <figref>4</figref> transmitted in the active set. In the exemplary embodiment, , the NACK message is demodulated and by the base stations <figref>4</figref> decoded and selector element <figref>14</figref> forwarded for processing. After processing of the NACK message, the data units are retransmitted using the procedure described above. In the exemplary embodiment combined selector element <figref>14</figref> the NACK signals, the from all base stations <figref>4</figref> received, in a NACK message and sends the NACK message to all base stations <figref>4</figref> in the active set.

In the exemplary embodiment, , mobile station <figref>6</figref> changes notice in the best C / I measurement and dynamically data transfers from different base stations <figref>4</figref> Request in each time slot, to increase the efficiency. In the exemplary embodiment, since data transmission only from a base station <figref>4</figref> in any given time slot <figref>4</figref> done, it can other base stations <figref>4</figref> in the active set not be known which data units, if any at all, to the mobile device <figref>6</figref> transfer were. In the exemplary embodiment, the transmitting information base station <figref>4</figref> selector element <figref>14</figref> about the Data transfer. The selector element <figref>14</figref> then sends a message to all base stations <figref>4</figref> in the active set. In the exemplary embodiment is transmitted from the Data believed to from the mobile device <figref>6</figref> received correctly were. Therefore, if the mobile station<figref>6</figref> data transmission from another base station <figref>4</figref> requests in the active set, transmits the new base station <figref>4</figref> the remaining data units. In the exemplary embodiment the base station transmits <figref>4</figref> in accordance with the last transmission update of the selector element <figref>14</figref>, Alternatively, selects the new base station <figref>4</figref> the next data units to transfer from using prediction schemes, based on metrics such as the average transfer rate and former Updates of the selector element <figref>14</figref>, These mechanisms minimize duplicate retransmissions the same data units by a plurality of base stations <figref>4</figref> in different time slots in a loss of efficiency result. If an earlier transmission was received in error, the base station <figref>4</figref> these data units except sequentially transferred new, since each data unit identified by a unique serial number is as described below. In the exemplary embodiment, if a hole (or non-transmitted Data units) is created (eg. As the result of handoff between a base station <figref>4</figref> to a different base station <figref>4</figref>) the missing data units are considered as if they would have been received in error. Mobile station <figref>6</figref> transmits NACK messages that the missing data units correspond to, and these data units be retransmitted.

In the exemplary embodiment, maintains each base station <figref>4</figref> in the active set, an independent data queue <figref>40</figref>. which the to mobile station <figref>6</figref> to be transmitted Data contains. The selected base station <figref>4</figref> transmitting data, which in its data queue <figref>40</figref> exist, in a sequential order, except for retransmissions of data units that were received in error, and for signaling messages. In the exemplary embodiment, be transferred Data units from the queue <figref>40</figref> after transfer deleted.

V. Other Considerations to data transfers on forward link

A important consideration is in the data communication system of the present invention the accuracy of the C / I estimates for the purpose of selecting the data rate for future transmissions. In the exemplary embodiment The C / I measurements are performed on the pilot signals during the time interval when the base station <figref>4</figref> Pilot sends signals. In the exemplary embodiment, since only the pilot signals during this pilot time interval are transmitted, the effects of are multiple paths and interference minimal.

In other implementations of the present invention, in which the Pilot signals continuously an orthogonal code channel are sent, similar to the IS-95 systems, can the effects of multi-path interference and the C / I measurements distort. Similar, if the C / I measurement on the data transmissions instead of the pilot signals accomplished is, can multiple paths and interference, the C / I measurements deteriorate. In both cases, when a base station <figref>4</figref> to a mobile station <figref>6</figref> sends, is , mobile station <figref>6</figref> in able, the C / I of the forward link signal to measure accurately because there are no other interfering signals. When the mobile device <figref>6</figref> though is in soft handoff and the pilot signals from multiple base stations <figref>4</figref> receives, is the mobile station <figref>6</figref> not to distinguish the location whether the base stations <figref>4</figref> transfer data have or not. In the worst case, mobile station<figref>6</figref> a measure high C / I at a first time slot, when no base stations <figref>4</figref> data to ir&lt;?page 15?&gt;gendein mobile device <figref>6</figref> Posted have, and data transmission receive in a second time slot, when all base stations <figref>4</figref> in same time slot to transmit data. The C / I measurements in the first time slot, when all base stations <figref>4</figref> in the Idling are, gives a false indication of the signal quality of the forward link in the second time slot since the status of the data communication system has changed. Therefore, the actual C / I deteriorates to be in the second time slot in a way that so reliable Decoding at the requested data rate is not possible.

the reverse extreme scenario exists when a C / I estimate by , mobile station <figref>6</figref> on maximum Interference based. However, the actual transfer when only the selected base station is carried out, sends. In this case, the C / I estimate and selected data rate conservative, and the transfer transmission takes place with a rate which is lower than that, the decoded reliable could be, so that the transmission efficiency is reduced.

In the implementation in which the C / I measurement on a continuous Pilot signal or the traffic signal is performed, the prediction the C / I in the second time slot based on the measurement of made C / I in the first time slot by three embodiments accurate will. In the first embodiment are data transfers from base stations <figref>4</figref> controlled so that the base stations <figref>4</figref> not frequently between the transmission and the idling state in consecutive time slots change. This can be achieved by enough data in the queue be classified (z. B. a predetermined number of information bits) prior to the actual data transmission to mobile devices <figref>6</figref>,

In the second embodiment transmits each base station <figref>4</figref> a forward activity bit (forward activity bit, hereinafter referred to as the FAC bit hereinafter) indicating whether a transfer in the next half frame is done. The use of the FAC bit is described in detail below described. Mobile station<figref>6</figref> performs the C / I measurement considering of the received FAC bit from each base station <figref>4</figref> by.

In the third embodiment, which corresponds to the scheme wherein an indication of the link quality to the base station <figref>4</figref> transfer is and which uses a centralized scheduling scheme, be the scheduling information indicating which of the base stations <figref>4</figref> in each time slot to transmit data have, the channel planner <figref>48</figref> made available. The channel scheduler<figref>48</figref> receives the C / I measurements from the mobile devices <figref>6</figref> and can C / I measurements based on its knowledge of the presence or absence of data transmission from each base station <figref>4</figref> in the data communication system to adjust. For example, mobile station<figref>6</figref> the C / I in the measure the first time slot when no adjacent base stations <figref>4</figref> send. The measured C / I is the channel planner <figref>48</figref> provided. The channel scheduler <figref>48</figref> White, that no adjacent base stations <figref>4</figref> in the first transmitted timeslot data have, because no through the channel planner <figref>48</figref> was planned. When planning for data transmission in the second time slot of the white channel scheduler <figref>48</figref>If at one or more adjacent base stations <figref>4</figref> transfer data will. The channel scheduler<figref>48</figref> can the C / I, the first in the Time slot was measured, adjust to take into account the additional interference, the mobile station <figref>6</figref> in the second time slot due to data transmissions by adjacent base stations <figref>4</figref> Will be received. Alternatively, if the C / I was measured in the first time slot when adjacent base stations <figref>4</figref> send and these adjacent base stations <figref>4</figref> in the second not send time slot, the channel planner can <figref>48</figref> the C / I measurement adapt to these additional to consider information.

A Another important consideration It is unnecessary retransmissions to minimize. Redundant retransmissions can result from it to the mobile device <figref>6</figref> is permitted, data transmitting different base stations <figref>4</figref> in consecutive to choose time slots. The best C / I measurement can be between two or more base stations <figref>4</figref> over consecutive Timeslots toggle when the mobile station <figref>6</figref> approximately equal C / I for these base stations <figref>4</figref> measures. The switching back and forth can due to deviations in the C / I measurements and / or changes caused in the channel conditions. Data transmission through different base stations <figref>4</figref> in successive time slots may result in a loss of efficiency.

the Change problem can be addressed through the application of hysteresis will. The hysteresis can be a signal level scheme, a timing scheme implemented or a combination of Signalniveau- and Time Schemes will. In the exemplary signal level scheme, the better C / I measurement of a different base station <figref>4</figref> in the Active Set not selected, as long as the C / I measurement the currently transmitting base station <figref>4</figref> at least the Hysteresis segröße not exceed. For example, it is assumed that the hysteresis is 1.0 dB and that the C / I measurement of the first base station <figref>4</figref> 3.5 dB and that &lt;?page 16?&gt;the C / I measurement of the second base station <figref>4</figref> 3.0 dB, in which first time slot. In the next Time slot, the second base station <figref>4</figref> not selected, long as its C / I measurement is at least 1.0 dB higher than that of the first base station <figref>4</figref>, Therefore, if the C / I measurement of the first base station <figref>4</figref> still 3.5 dB at the next time slot is, the second base station <figref>4</figref> not selected, long their C / I measurement is not at least 4.5 dB.

In the exemplary timing scheme, the base station <figref>4</figref> data packets to the mobile device <figref>6</figref> over a predetermined number of time slots. The mobile station<figref>6</figref> is does not allow a different transmitting base station <figref>4</figref> within the predetermined number of time slots to choose. Mobile station<figref>6</figref> puts measuring the C / I of the current transmitting base station <figref>4</figref> in each time slot and selects continued the data rate in response to the C / I measurement.

Still Another important consideration is the efficiency of data transmission. Referring to <figref idrefs="S88">4E</figref> and <figref idrefs="S88">4F</figref> contains any package format <figref>410</figref> and <figref>430</figref> Data and overhead bits. In the exemplary embodiment, is the number of overhead bits for all data rates. at the highest Data rate is the percentage of the overheads with respect to the Package size relative small and the efficiency is high. At the lower data rates can the overhead bits a greater percentage the package includes. The inefficiency of the lower data rates can be improved by transmitting of variable length data packets to mobile station <figref>6</figref>, The data packets of variable length can and divided to mobile station <figref>6</figref> over several transmit time slots will. Preferably, the data packets are of variable length to the mobile device <figref>6</figref> over consecutive transmit time slots, in order to simplify the processing. The present invention is on the use of various Pa ketgrößen for various supported data rates aligned to the entire transmission efficiency to improve.

VI. Architecture of the forward link

In the exemplary embodiment, the base station <figref>4</figref> With the maximum power for the base station <figref>4</figref> available , and at the maximum data rate of the data communication system by a single mobile device <figref>6</figref> in any given time slot is supported. The maximum data rate that supports can be, is dynamic and depends of the C / I of the forward link signal from which by mobile station <figref>6</figref> measured is. Preferably, the base station transmits<figref>4</figref> in any given Time slot only to a mobile station <figref>6</figref>,

Around data transmission to support, includes the forward link four time multiplexed channels: the pilot channel (pilot channel), the power control channel (power control channel), the control channel (control channel) and the traffic channel (Traffic channel). The function and implementation of each of these channels is described below. In the exemplary embodiment, include the traffic and power control channels each have a number of orthogonally spread Walsh channels. In the present invention, the traffic channel is used, traffic data and paging messages to the mobile device <figref>6</figref> transferred to. If he for transmission is used by paging messages, the traffic channel is in this specification also referred to as a control channel.

In the exemplary embodiment, is a bandwidth of the forward link elected by 1.2288 MHz. This choice of bandwidth allows the use of existing hardware components, encoding a CDMA system have been designed that the IS-95 standard corresponds. However, the data communication system of the present invention be adapted for use with different bandwidths to the capacity to improve and / or to meet system requirements. For example , a bandwidth of 5 MHz are used to increase the capacity. furthermore can the bandwidths of the forward link and the reverse link be different (eg. for example, a 5 MHz bandwidth on the forward link and a bandwidth of 1.2288 MHz on the reverse link) to the connection capacity of the demand better adapt.

In the exemplary embodiment, have the short PN_I- And PN_Qcodes 2¹⁵ PN-codes of the same length passing through the IS-95 standard are specified. In the chip rate of 1.2288 MHz repeated the short PN sequences all 26.67 ms (26.67 ms = 2¹⁵/ 1.2288 · 10⁶). In the exemplary embodiment, , the same short PN codes of all base stations <figref>4</figref> within the data communication system used. However, each base station is<figref>4</figref> by a unique offset of the basic short PN sequences identified. In the exemplary embodiment, the offset in increments of 64 chips. Other bandwidth and PN codes can be used be and are within the scope of the present invention.

&lt;?page 17?&gt;

VII. Transport channel forward link

On Block diagram of an exemplary architecture of the forward link the present invention is in <figref idrefs="S83">3A</figref> shown. The data is divided into data packets and a CRC encoder <figref>112</figref> provided. For each Data packet generated by the CRC encoder <figref>112</figref> Frame Check bits (Z. B. the CRC parity bits) and adds the Codetail bits one. The formatted packet of CRC encoder<figref>112</figref> includes the data, the frame check bits, and code tail bits, and other overhead bits, which are described below. The formatted packet is an encoder<figref>114</figref> provided, the in the exemplary embodiment, the package in accordance encoded with the encoding format, which in the aforementioned US patent application no. is 08 / 743.688 disclose. Other encoding formats can also be used and are within the scope of the present invention. the encoded packet from encoder <figref>114</figref> is the interleaver <figref>116</figref> provided, the reorders the code symbols in the packet. The nested (interleaved) Package is the frame puncture element <figref>118</figref> provided, which removes a part of the package in a way that the described below is. The dotted package is the multiplier<figref>120</figref> provided, of the data with the encryption sequence of the scrambler <figref>122</figref> encrypted. the Puncturing element <figref>118</figref> and the encryptor <figref>122</figref> are below described in detail. The output from the multiplier<figref>120</figref> includes the encrypted Package.

the encrypted Package is a controller for variable rates <figref>130</figref> provided for unbundling (demultiplexing) the packet into K parallel inphase and quadrature channels, where K is dependent on the data rate. In the exemplary embodiment, is encrypted package first in the in-phase (Q) (I) and quadrature demultiplexed streams. In the exemplary embodiment includes the I-stream just Index symbols and the Q stream comprises odd index symbols. Each stream is further parallel in K unbundled channels so that the symbol rate of each channel is fixed for all data rates. The K channels each stream are a Walsh coding <figref>132</figref> provided, the each channel with a Walsh function encoding (covers) to orthogonal channels provide. The orthogonal channel data is a reinforcing element<figref>134</figref> provided, which scales the data to maintain a constant total energy per chip (And hence constant output power) for all data rates to maintain. The scaled data from gain element <figref>134</figref> are a Multiplexer (MUX) <figref>160</figref> provided for multiplexing (bundling) of Data with the preamble. The preamble is discussed in detail below. The output from MUX<figref>160</figref> becomes a multiplexer (MUX) <figref>162</figref> provided for multiplexing of the traffic data, the power control bits, and the pilot data. The output of the MUX <figref>162</figref> comprises the I Walsh channels and the Q Walsh channels.

On Block diagram of the exemplary modulator for modulating the data is used, in <figref idrefs="S85">3B</figref> shown. The I Walsh channels and the Q Walsh channels are adder <figref>212a</figref> or. <figref>212b</figref> provided that the K Walsh channels sum, the signals I_sum or Q_sum provide. The signals I_sum and Q_sum will the complex multiplier <figref>214</figref> provided. The complex multipliers <figref>214</figref> also receives the signals and PN_I PN_Q from the multipliers <figref>236a</figref> or. <figref>236b</figref> and multiplied the two complex inputs in accordance with the following equation: <st32:df xmlns:st32="http://lighthouseip.com/">(I<st32:sub>mult</st32:sub> + jQ<st32:sub>mult</st32:sub>) = (I<st32:sub>sum</st32:sub> + jQ<st32:sub>sum</st32:sub>) · (PN_I + JPN_Q) = (I<st32:sub>sum</st32:sub>· PN_I - Q<st32:sub>sum</st32:sub>· PN_Q) + J (I<st32:sub>sum</st32:sub>· PN_Q + Q<st32:sub>sum</st32:sub>· PN_I) (2)</st32:df>wherein I_mult and Q_mult the Outputs from the complex multiplier <figref>214</figref> are and j the complex representation is. The signals I_mult and Q_mult be Filter <figref>216a</figref> or. <figref>216b</figref> provided, which filter the signals. The filtered signals from filters<figref>216a</figref> and <figref>216b</figref> will multipliers <figref>218a</figref> or. <figref>218b</figref> provided, the signals with the inphase sinusoid COS (w_ct) and the quadrature sinusoid SIN (w_ct) multiplied. The I modulated and Q modulated signals the adder <figref>220</figref> provided, which adds the signals, the forward modulation waveform S (t) provide.

In the exemplary embodiment, the data packet is spread with the long PN code and the short PN codes. encrypted The long PN code the packet such that only the mobile station <figref>6</figref>, To which the packet is directed, is able to decrypt the packet. In the exemplary embodiment, are the pilot bits and power control bits and the control channel packet spread with the short PN codes but not the long PN code, to it all mobile devices <figref>6</figref> to enable, to receive these bits. The long PN sequence is determined by the long code generator<figref>232</figref> generated and the multiplexer (MUX) <figref>234</figref> provided. The length PN mask determines the offset of the long PN sequence and is the Target mobile device <figref>6</figref> clearly assigned. The output from MUX<figref>234</figref> is the long PN sequence while the data portion of the transmission and zero otherwise (z. B. during of the pilot portion and the power control portion). The controlled (gated) long PN sequence from MUX <figref>234</figref> and the short PN_I- And PN_QSequences of the Short code Generator <figref>238</figref> are the multipliers <figref>236a</figref> or. <figref>236b</figref> provided, the two sets of sequences &lt;?page 18?&gt;multiply the signals PN_I or PN_Q form. The signals PN_I and PN_Q are the complex multiplier<figref>214</figref> provided.

the Block diagram of the exemplary traffic channel, which in the <figref idrefs="S83">3A</figref> and <figref idrefs="S85">3B</figref> shown is, is one of countless architectures, data encoding and modulation on the forward link show. Other architectures, such. As the architecture for the forward link traffic channel in the CDMA system, conforming to the IS-95 standard, can also be used and are within the scope of the present invention.

In the exemplary embodiment, are the data rates by the base stations <figref>4</figref> get supported, predetermined, and supported each Data rate is assigned a unique rate index. Mobile station<figref>6</figref> chooses a supported Data rates based on the C / I measurement. Since the requested data rate to a base station <figref>4</figref> must be sent to specify, that the base station <figref>4</figref> the data with the requested Sends data rate, is a compromise between the number of supported data rates and the number of bits for identifying the requested Data rate required will be done. In the exemplary embodiment, the number supported data rates <figref>7</figref>And it is a 3-bit rate index is used, in order to identify the requested data rate. An exemplary Definition of support Data rates is illustrated in Table 1 below. Different definitions supported Data rates can are contemplated and are within the scope of present invention.

In the exemplary embodiment, is the minimum data rate of 38.4 Kbps and the maximum data rate is 2.4576 Mbps. The minimum data rate is selected based on the worst C / I measurement in the system, the process gain the system, the design of the error correcting code and the desired Level of performance. In the exemplary embodiment, the supported data rates are selected, that the difference between successive data rates 3 dB. The 3 dB increment is a compromise between different factors, which include: the accuracy of the C / I measurement that by mobile station <figref>6</figref> achieved may be, the losses (or inefficiencies) which of the quantization the data rate and the result based on the C / I measurement Number of bits (or the bit rate) used for transferring the required Data rate of the mobile station <figref>6</figref> at the base station <figref>4</figref> needed will. More Compatible Data rates requires more bits to the requested data rate to identify, but they allow a more efficient use the forward link due to the smaller quantization error between the calculated maximum data rate and the data rate support. The present invention is the use of any number of supported data rates and other Data rates than those listed directed in Table 1 below. table 1 - traffic channel parameters <img img-content="tb" img-format="tif" he="76" wi="146" file="00420001.tif" />&lt;?page 19?&gt;<img img-content="tb" img-format="tif" he="19" wi="146" file="00430001.tif" /><ul><li>Note: (1) 16-QAM modulation</li></ul>

On Diagram of an exemplary frame structure of the forward link the present invention is in <figref idrefs="S84">4A</figref> shown. The traffic channel transmission is divided into frames, which in the exemplary embodiment, than the length of the short PN sequences or 26.67 ms are defined. Each frame can carry control channel information addressed to all mobile devices <figref>6</figref> directional are (control channel frame), traffic data to a mobile station <figref>6</figref> directional are (traffic frame), or it can be empty (idle frame, idle frame). The content of each frame is determined by the scheduling, by the transmitting base station <figref>4</figref> is carried out. In the exemplary embodiment, each frame comprises 16 time slots, each time slot a Duration of 1.667 ms. has. A time slot of 1.667 msec is adequate, to allow the mobile station <figref>6</figref> to enable, the C / I measurement of the forward link signal perform. A time slot of 1.667 msec also represents a sufficient amount of time for efficient packet data transmission ready. In the exemplary embodiment, each time slot further divided into 4 quarters slots.

In of the present invention, each data packet over a transferred or more time slots, such as shown in Table 1 below. In the exemplary embodiment, each forward link data packet 1024 or 2048 bits. Therefore, the number of time slots which for transferring of the data packet are required, depending on the data rate, and ranges from 16 time slots for the rate of 38.4 Kbps up to a time slot for the rate 1.2288 Mbps and higher.

On exemplary diagram of the forward link slot structure of the the present invention is in <figref idrefs="S86">4B</figref> shown. In the exemplary embodiment form each slot comprises three of the four time multiplexed channels, the Traffic channel, the control channel, the pilot channel and the power control channel. In the exemplary embodiment, the pilot and power control channels are transmitted in two pilot and power control bursts, which are arranged in the same positions in each time slot. The pilot and power control bursts are described in detail below.

In the exemplary embodiment, is the interleaved packet of the interleaver <figref>116</figref> punctured to the pilot and power control bursts accommodate. In the exemplary embodiment each interleaved packet comprises 4096 code symbols and the first 512 code symbols are punctured, as in <figref idrefs="S87">4D</figref> shown. The remaining code symbols are time-warped to the transmission intervals equalize the traffic channel.

The punctured code symbols are scrambled to the data before Application of orthogonal Walsh codes randomly to arrange. The random arrangement limits the maximum-to-average envelope (peak-to-average envelope) the modulated waveform S (t). The encryption sequence can with a linear Feedback shift register be generated, as is known in the art. In the exemplary embodiment the encryptor (Scrambler) <figref>122</figref> the LC status at the start of each slot filled. In the exemplary embodiment, is the clock of scrambler <figref>122</figref> synchronous with the clock of interleaver <figref>116</figref>However, during the Pilot and power control bursts stopped.

In the exemplary embodiment, are the forward Walsh channels (for the traffic channel and the power control channel) are orthogonal with 16-bit Walsh codes with the solid Chip rate of 1.2288 Mcps spread. The number of parallel orthogonal channels K per inphase and quadrature signal is a function of the data rate, as shown in Table 1 below. In the exemplary embodiment, for lower Data rates, the inphase and quadrature Walsh codes as orthogonal selected amounts, to crosstalk to the demodulator phase estimate error to minimize. For example, for 16 Walsh channels a exemplary Walsh assignment W₀ to W₇ for the in-phase signal, and W₈ to W₁₅ for the quadrature signal.

In the exemplary embodiment, is QPSK modulation for Data rates of 1.2288 Mbps and uses low. For QPSK modulation includes each Walsh channel 1 bit. In the exemplary embodiment, 16-QAM at the highest Data rate of 2.4576 Mbps is used, and the encrypted Data in 32 parallel streams unbundled each 2 bits wide, 16 parallel streams fair the in-phase signal and 16 parallel streams for the Quadrature signal. In the exemplary embodiment, the LSB (Least Significant Bit) for each 2-bit symbol, the former Symbol output from the interleaver <figref>116</figref>, In the case&lt;?page 20?&gt;plary embodiment be the QAM modulation inputs of (0, 1, 3, 2), in accordance mapped to modulation values ​​of (+3, +1, -1, -3). The application of other modulation schemes, such as m-times phase shift keying PSK, in Are contemplated and within the scope of the present Invention.

The Inphase and quadrature Walsh channels are scaled prior to modulation to maintain a constant total transmit power maintain that regardless is of the data rate. The gain settings normalized to a unity reference, the unmodulated BPSK equivalent is. The normalized channel gains G as a function of Number of Walsh channels (Or data rate) are shown in Table 2 below. In Table 2 it is also the average power per Walsh channel (inphase or quadrature) listed, such that the total normalized power is equal to the first Note that the channel gain for 16-QAM into account the fact that the normalized energy per Walsh chip is 1 for QPSK and 16-QAM 5. table 2 - Traffic Channel Orthogonal Channel reinforcements <img img-content="tb" img-format="tif" he="69" wi="147" file="00460001.tif" />

In the present invention is a preamble in each traffic frame punctured to the mobile device <figref>6</figref> at synchronization with the first slot of each transmission to support variable rate. In the exemplary embodiment, the preamble a sequence anywhere Zero and said for a transport frame is spread with the long PN code, however, for a control channel frame is not spread with the long PN code. In the exemplary embodiment, the preamble unmodulated BPSK, the west with the Walsh code₁ orthogonally is spread. The use of a single orthogonal channel minimizes the peak-to-average envelope. The use of a non-zero Walsh codes W₁ also minimizes false pilot detection, for this Traffic frames, the pilot with the Walsh code W₀ spread is, and both the pilot and the preamble is not long with the PN code are spread.

The preamble is in the traffic channel stream at the start of the package bundled (multiplexed) for a period, which is a function of the data rate. The length of the preamble is such that the preamble overhead for all Data rates approximately is constant, while the probability of false detection minimized. A summary of the preamble as a function of Data rates is shown in Table 3 below. Note that the Preamble 3.1 comprises% or less of a data packet. &lt;?page 21?&gt; table 3 - Preamble Parameters <img img-content="tb" img-format="tif" he="57" wi="142" file="00470001.tif" />

VIII. Forward link traffic frame format

In the exemplary embodiment, of each data packet by the addition of frame check bits, Code tail bits, and other control fields formatted. In this Specification is one octet as 8 information defined, and a data unit is a single octet and comprises 8 information.

In the exemplary embodiment, supports the forward link two data packet formats which in the <figref idrefs="S88">4E</figref> and <figref idrefs="S88">4F</figref> illustrated are. The packet format<figref>410</figref> comprises five fields and packet format <figref>430</figref> includes nine fields. The packet format<figref>410</figref> is used when the Data packet to mobile station <figref>6</figref> transfer to be, contains enough data, all available Octets in DATA field <figref>418</figref> completed in full. If the amount to be transferred to the Data is less than the available Octets in the DATA field <figref>418</figref> is, the packet format is <figref>430</figref> used. The octet is not used, all filled with null and be as PADDING field <figref>446</figref> designated.

In the exemplary embodiment, contain the Frame Check Sequence (FCS) fields <figref>412</figref> and <figref>432</figref> the CRC parity bits, by the CRC generator <figref>112</figref> are generated (see <figref idrefs="S83">3A</figref>) in accordance with a predetermined generator polynomial. In the exemplary embodiment is the CRC polynomial g (x) = x¹⁶ + x¹² + x⁵ + 1, although other polynomials used can be and are within the scope of the present invention. In the exemplary embodiment, are the CRC bits on the FMT, SEQ, LEN, DATA, and PADDING fields calculated. This provides Error detection via all bits, except the code tail bits in TAIL fields <figref>420</figref> and <figref>448</figref>. the above transfer the traffic channel on the forward link will. In the alternative embodiment are the CRC bits only the DATA field calculated. In the exemplary embodiment, containing FCS fields <figref>412</figref> and <figref>432</figref> 16 CRC parity bits, although other CRC generators providing different number of parity bits, can be used and are within the scope of the present invention. Although FCS fields <figref>412</figref> and <figref>432</figref> the present invention in the context of CRC parity bits have been described, other verification sequences of frames be used and are within the scope of the present Invention. For example, a checksum calculated for the packet and in Provided the FCS field.

In the exemplary embodiment, contain the frame format (FMT) fields <figref>414</figref> and <figref>434</figref> a control, which indicates whether the data frame only data octets (packet format <figref>410</figref>) or data and padding octets and zero or more messages (Packet format <figref>430</figref>) Contains. In the exemplary embodiment, corresponds to a low value for the FMT field <figref>414</figref> the packet format <figref>410</figref>, alternative corresponds to a high value for the FMT field <figref>434</figref> the packet format <figref>430</figref>,

The Sequence Number (SEQ) fields <figref>416</figref> and <figref>442</figref> identify the first data unit in the data fields <figref>418</figref> or. <figref>444</figref>, The sequence number (sequence number) or serial number allowed it is that data except the series to mobile station transmitted 6 be such. as for retransmitting packages that have been received in error. The allocation of Sequence number at the level of data unit eliminates the need for a Frame fragmentation protocol for retransmission. The sequence number allows the mobile device <figref>6</figref> Also, double Data units to be recognized. Upon receipt of the FMT, SEQ, and LEN fields is the mobile station <figref>6</figref> in determine the location, receive data units in each time slot were without the use of special signaling messages.

&lt;?page 22?&gt;

The Number of bits that represent the sequence number is dependent on the maximum number of data units from transmitting in a time slot can be, and on the delays when retransmission of data in the worst case. In the exemplary embodiment, each data unit is identified by a 24-bit sequence number. At the data rate of 2.4576 Mbps, the maximum number of Data units which can be transmitted in each slot, approximately the 256th Eight bits are required to identify each of the data units. Furthermore, it can be calculated that the delays in the re-transmission of data is less than 500 ms in the worst case. The delays when retransmission include the time for a NACK message by mobile station <figref>6</figref> necessary is, for retransmitting the information and for the number of retransmission attempts, by burst error runs caused in the worst case. Therefore permit it 24 bits to the mobile station <figref>6</figref>. to identify the data units received without ambiguity properly. The number of bits in SEQ fields <figref>416</figref> and <figref>442</figref> can elevated or decreased, depending the size of DATA field <figref>418</figref> and the delays at the retransmission. The use of a different number of bits for SEQ fields <figref>416</figref> and <figref>442</figref> lie within the range of the present invention.

If the base station <figref>4</figref> less data to transfer a mobile device <figref>6</figref> be present as a place in the DATA field <figref>418</figref> is available, the packet format is <figref>430</figref> used. The packet format <figref>430</figref> allowing the base station <figref>4</figref>. any number of data units to mobile station <figref>6</figref> transferred to, up to the maximum number of available data units. In the exemplary embodiment is a high value of the FMT field <figref>434</figref> that the base station <figref>4</figref> the package format <figref>430</figref> transfers. Within the packet format <figref>430</figref> includes the LEN field <figref>440</figref> the Value of the number of data units transmitted in that packet will. In the exemplary embodiment, the LEN field<figref>440</figref> 8 Bits long, as the DATA field <figref>444</figref> be from 0 to 255 octets can.

The DATA fields <figref>418</figref> and <figref>444</figref> include to mobile station <figref>6</figref> to be transmitted Data. In the exemplary embodiment, for packet format<figref>410</figref>. each data packet comprises 1024 bits of which 992 are data bits. However, Data packets with variable length be used to increase the number of information bits, and are within the scope of the present invention. For the packet format<figref>430</figref> becomes the size of DATA field <figref>444</figref> by the LEN field <figref>440</figref> certainly.

In the exemplary embodiment, , the packet format <figref>430</figref> be used to zero or more to transmit signaling messages. The Signalisierungslänge- (SIG LEN) field <figref>436</figref> contains the length the subsequent signaling messages in octets. In the exemplary embodiment won the SIG LEN field <figref>436</figref> a length of 8 bits. The SIGNALING field<figref>438</figref> contains the signaling messages. In the exemplary embodiment, , each signaling message Nachrichtenidentifizierungs- (MESSAGE ID) field, a Nachrichtenlänge- (LEN) Field and a message payload, as described below. The PADDING field<figref>446</figref> contains padding octets which in the exemplary embodiment to 0 × 00 (Hex) are set. The PADDING field<figref>446</figref> is used, since the base station <figref>4</figref> fewer data octets to mobile station <figref>6</figref> to transfer may be than the number of octets in the DATA field <figref>418</figref> Are available. When this occurs, contains the PADDING field <figref>446</figref> Paddingoktette enough to the Since unused tenfelder replenish. The PADDING field <figref>446</figref> has a variable length, and depends on the length of the DATA field <figref>444</figref> from.

the last field of packet formats <figref>410</figref> and <figref>430</figref> are the TAIL fields <figref>420</figref> or. <figref>448</figref>, The TAIL fields<figref>420</figref> and <figref>448</figref> contain neutral (0 × 0) Code tail bits, which is used to the encoder <figref>114</figref> (please refer <figref idrefs="S83">3A</figref>) bring to a known state at the end of each data packet. The code tail bits allow encoder <figref>114</figref>, the package suitable split so that only bits from one packet in the coding process be used. The code tail bits allow the decoder within of the mobile <figref>6</figref>. the packet boundaries during the to determine decoding process. The number of bits in TAIL fields<figref>420</figref> and <figref>448</figref> depends on the Design of the encoder <figref>114</figref> from. In the exemplary embodiment, the TAIL fields <figref>420</figref> and <figref>448</figref> long enough to the encoder <figref>114</figref> bring to a known state.

The two packet formats described above are exemplary Formats that can be used, to transfer of data and signaling messages to assist. Various other Package formats are generated to the requirements of a particular communication system to fulfill. Likewise can be made to a communication system to more accommodate than the two packet formats described above.

&lt;?page 23?&gt;

IX. Forward link control channel frame

In of the present invention, the traffic channel is also used to messages from the base station <figref>4</figref> to mobile devices <figref>6</figref> transferred to. The types for the transferred Messages include: (1) handoff instruction message, (2) paging messages (Z. B. Call a particular mobile device <figref>6</figref>, For which Data in the queue for This mobile device <figref>6</figref> are) (3) short data packets for a particular mobile device <figref>6</figref> and (4) ACK or NACK messages for data transmission on the reverse link (The later here to be discribed). Other types of messages can also be transmitted on the control channel be and are within the scope of the present invention. After completion of the phase of the connection monitored mobile station <figref>6</figref> the Control channel for paging messages and begins transmission the reverse link pilot signal.

In the exemplary embodiment, is the control channel bundled time (Time multiplexed) with the traffic data on the traffic channel, as in <figref idrefs="S84">4A</figref> shown. The Mobile Devices<figref>6</figref> identify the control message by detecting a preamble, which with a predetermined PN code is encoded. In the exemplary embodiment, the control messages are transmitted at a fixed rate, the by mobile station <figref>6</figref> during the Construction is set. In the preferred embodiment, the data rate is the control channel <figref>76</figref>.<figref>8</figref> Kbps.

Of the Control channel transmits messages in control channel capsules. The diagram of an exemplary control channel capsule is in <figref idrefs="S88">4G</figref> shown. In the exemplary embodiment includes each capsule a preamble <figref>462</figref>. the control payload, and CRC parity bits <figref>474</figref>, The tax load comprises one or more messages and, if necessary, padding bits <figref>472</figref>, Each message includes a message identifier (MSG ID)<figref>464</figref>. the message length (LEN) <figref>466</figref>, Optional address (ADDR) <figref>468</figref> (Z. B. If the message to a particular mobile device <figref>6</figref> directional is) and a message payload <figref>470</figref>, In the exemplary embodiment the messages are aligned with the octet boundaries. The exemplary Control channel capsule in <figref idrefs="S88">4G</figref> shown is, comprises two broadcast messages the all mobile devices <figref>6</figref> directional are, and a message to a particular mobile station <figref>6</figref> directional is. The MSG ID field<figref>464</figref> determines whether the message Address field requires or not (z. B. if there is a broadcast or a particular message is).

X. forward link pilot channel

In the present invention provides a a forward link pilot channel Pilot signal that the mobile radio devices <figref>6</figref> for the first Structure, phase recovery (Phase recovery), the timing recovery (timing recovery) and the ratio-combining (Ratio combining) may be used. These applications are similar to those CDMA communication systems that comply with the standard 15-95. In the exemplary embodiment, is the pilot signal by the mobile devices <figref>6</figref> used to the C / I measurement to perform.

the exemplary block diagram of the forward link Pilo tkanals the present invention is in <figref idrefs="S83">3A</figref> shown. The pilot data comprises a sequence of all zeros (or all Ones), the multiplier the <figref>156</figref> to be provided. multiplier <figref>156</figref> encodes the pilot data with Walsh code W₀, Since Walsh code W₀ a Sequence of all zeros, the output of the multiplier are <figref>156</figref> the Pilot data. The pilot data by the MUX<figref>162</figref> chronologically bundled and the I Walsh channel provided by the short PN₁Code within complex multiplier <figref>214</figref> spread (see <figref idrefs="S85">3B</figref>). In the exemplary embodiment, the pilot data is not spread with the long PN code, which during Pilot burst by MUX <figref>234</figref> is turned off to the Reception by all mobile device <figref>6</figref> to enable. The pilot signal is thus an unmodulated BPSK signal.

On Diagram illustrating the pilot signal is in <figref idrefs="S86">4B</figref> shown. In the exemplary embodiment, each time slot comprises two pilot bursts <figref>306a</figref> and <figref>306b</figref>. which occur at the end of the first and third quarter of the time slot. In the exemplary embodiment, is the duration of each pilot burst <figref>306</figref> 64 Chips (Tp = 64 chips). In the absence of traffic data or control channel data, the base station transmits<figref>4</figref> just the pilot and power control bursts, which in a discontinuous Waveform results, with bursts of a periodic rate of 1200Hz. The pilot modulation parameters are tabulated in Table 4.

&lt;?page 24?&gt;

XI. Reverse link power control

In of the present invention, the forward link power control channel used to send the power control command which is used to control the transmission power of the reverse link transmission from the remote device <figref>6</figref> used is. On the reverse link acts each transmitting mobile station <figref>6</figref> as a source interference for all other mobile devices <figref>6</figref> in the network. To minimize interference on the reverse link and the capacity to maximize the transmission power of each mobile unit is <figref>6</figref> by two power control loops controlled. In the exemplary embodiment, the power control loops are similar to those of the CDMA system, which discloses in detail 5,056,109 is described in US Pat. No. with the Entitled "METHOD AND APPARATUS FOR CONTROLLING TRANSMISSION POWER IN A CDMA CELLULAR MOBILE TELEPHONE SYSTEM " assigned to the assignee of the present invention. Other can power control mechanisms are also contemplated and are within the scope of the present invention.

The first power control loop adjusts the transmit power of the mobile radio device <figref>6</figref> so that the signal quality the reverse link is maintained at a set level. The signal quality is measured as the energy-per-bit-to-noise-plus-interference ratio E_b/ I₀ the reverse link signal, the at the base station <figref>4</figref> Will be received. This set Level is also known as the E_b/ I₀-Setpoint Referred. The second power control loop adjusts the set point such that the wished Level of performance, as measured by the frame error rate (Frame Error Rate, FER) is maintained. The power control on the reverse link critical since the transmission power of each mobile unit <figref>6</figref> interference for others cellular devices <figref>6</figref> in means the communication system. Minimizing the transmit power the reverse link reduces the interference and increases the capacity of the reverse link.

Within the first power control loop, the E_b/ I_O the reverse link signal at the base station <figref>4</figref> measured. The base station<figref>4</figref> compares then the measured E_b/ I_O With the Setpoint. If the measured E_b/ I_O greater than the setpoint is, the base station transmits <figref>4</figref> a Power control message to mobile station <figref>6</figref>To the transmit power to reduce. Alternatively, if the measured E_b/ I_O is below the set point, the base station transmits <figref>4</figref> a Power control message to mobile station <figref>6</figref>To the transmit power to increase. In the exemplary embodiment, is implemented with one power control bit, the power control message. In the exemplary embodiment, has a high value for the power control, mobile station <figref>6</figref> to, its transmit power to increase, and a low value, the mobile radio device <figref>6</figref> to, its transmit power to reduce.

In the present invention, the power control bits for all mobile devices <figref>6</figref> in Communication with each base station <figref>4</figref> transmitted on the power control channel. In the exemplary embodiment, includes the power control channel up to 32 orthogonal channels which are spread with the 16-bit Walsh codes. Each Walsh channel transmits a Rückwärtsleistungssteuerbit (Reverse Power Control, RPC) or one FAC bit at periodic intervals. Each active mobile station <figref>6</figref> becomes assigned an RPC index which the Walsh code and QPSK modulation phase (Z. B. in-phase or quadrature) for transmission of the RPC bit stream defined, attached to the mobile device <figref>6</figref> is addressed. In the exemplary embodiment, is the RPC index 0 for the FAC bit reserved.

the exemplary block diagram of the power control channel is in <figref idrefs="S83">3A</figref> shown. The RPC bits are the symbol repeater <figref>150</figref> provided, of each RPC bit is repeated a predetermined number. The repeated be RPC bits the Walsh coding <figref>152</figref> provided that the bits encoded with the Walsh codes corresponding to the RPC indices. The coded bits are the reinforcing member <figref>154</figref> provided, the scales the bits prior to modulation so as a constant total maintain transmission power. In the exemplary embodiment, are the gains the RPC Walsh channels normalized so that the total RPC channel power is equal to the total available Transmission power is. The gains the Walsh channels can as a function of time for efficient utilization of the entire Transmission power of the base station can be varied while a reliable RPC transmission to all active mobile devices <figref>6</figref> maintained. In the exemplary embodiment, are the gains the Walsh channels of inactive mobile devices <figref>6</figref> on set zero. Automatic power control of the RPC Walsh channels is possible under Use of estimates the quality measurement the forward link the corresponding DRC channel of mobile devices <figref>6</figref>, The scaled RPC bits from the reinforcing member <figref>154</figref> be the MUX <figref>162</figref> provided.

In the exemplary embodiment, be the RPC indices 0 to 15 in each case the Walsh codes W₀ to W₁₅ assigned and around the first pilot burst around within a slot (RPC bursts <figref>304</figref> in <figref idrefs="S86">4C</figref>) &lt;?page 25?&gt;transfer. The RPC indices <figref>16</figref> to <figref>31</figref> will each of the Walsh codes W₀ to W₁₅ and assigned to the second pilot burst around within a slot (RPC bursts <figref>308</figref> in <figref idrefs="S86">4C</figref>) transfer. In the exemplary embodiment, be the RPC bits BPSK modulated with the even Walsh codes (z. B. W₀. W₂, W₄ etc.) modulated on the in-phase signal and the odd Walsh codes (z. B. W₁, W₃, W₅ etc.) modulated on the quadrature signal. To reduce the peak-to-average envelope, it is preferable to balance the inphase and quadrature power. to continue crosstalk to minimize due to demodulator phase estimate error, is it is preferable to the in-phase and quadrature signals orthogonal codes assign.

In the exemplary embodiment, can up to 31 RPC bits on RPC-31 Walsh channels in each transmitted timeslot will. will guide shape in the exemplary From 15 RPC bits transmitted in the first slot half transmitted and 16 RPC bits in the second half slot. The RPC bits by adder <figref>212</figref> (please refer <figref idrefs="S85">3B</figref>) Combined and the composite waveform of the power control channel is in <figref idrefs="S86">4C</figref> shown.

On Time diagram of the power control channel is in <figref idrefs="S86">4B</figref> shown. In the exemplary embodiment, is the RPC bit rate <figref>600</figref> bps or 1 RPC bit per time slot. Each RPC bit is time multiplexed- (Time multiplexed) and is 2 RPC bursts (z. B. RPC bursts <figref>304a</figref> and <figref>304b</figref>) transfer, as in the <figref idrefs="S86">4B</figref> and <figref idrefs="S86">4C</figref> shown. In the exemplary embodiment, each RPC burst <figref>32</figref> PN chips (or 2 Walsh symbols) width (Tpc = 32 chips) and the total width of each RPC bit is 64 PN chips (Or 4 Walsh symbols). Other RPC bit rates can change the number of repeated symbols are received. For example can an RPC bit rate of 1200 bps (up to 63 mobile phones <figref>6</figref> simultaneously support or to increase the power control rate) can be obtained by transferring the first set of 31 RPC bits on RPC bursts <figref>304a</figref> and <figref>304b</figref> and the second set of 32 RPC bits on RPC bursts <figref>308a</figref> and <figref>308b</figref>, In this case, in-phase and quadrature signals are all Walsh codes used. The modulation parameters for the RPC bits are summarized in Table 4 below. table 4 - Pilot and power control modulation parameters <img img-content="tb" img-format="tif" he="32" wi="143" file="00570001.tif" />

Of the is power control channel by bursts characterized ( "bursty nature ") because that Number of mobile phones <figref>6</figref> in Communication with each base station is smaller than the number of available RPC Walsh channels can be. In this situation, some RPC Walsh channels are set to zero by suitable adjustment of the gains of gain element <figref>154</figref>,

In the exemplary embodiment, be the RPC bits to the mobile device <figref>6</figref> without coding or transmitted nesting, to processing delays to minimize. Furthermore, it affects the erroneous reception of Power control bits not detrimental to the data communication system of the present invention, since the error by the power control loop in the next Time slot can be corrected.

In the present invention may the mobile devices <figref>6</figref> in the Soft handoff with a plurality of base stations <figref>4</figref> are on the reverse link. the Method and apparatus for Power control on the reverse link for the mobile device <figref>6</figref> in the Soft handoff is disclosed in the aforementioned US Pat. No. 5,056,109. Mobile station<figref>6</figref> in the monitored soft handoff the RPC Walsh channel of each base station <figref>4</figref> in the Active Set and combines the RPC bits in accordance with the method, disclosed in the aforementioned US Pat. No. 5,056,109. In the first embodiment leads the mobile device <figref>6</figref> the logical OR of the power reduction commands. Mobile station<figref>6</figref> reduced the transmission power, if just any of the received RPC bits the mobile device <figref>6</figref> instructs to reduce the transmission power. In the second embodiment , mobile station <figref>6</figref> in the Soft handoff the preliminary rounds (drank decisions) of the RPC bits combine before a final Decision (hard decision) applies. Other embodiments for processing of the received RPC bits can are contemplated and are within the scope of present invention.

&lt;?page 26?&gt;

In the present invention is the FAC bit mobile devices <figref>6</figref> at, whether the traffic channel of the associated pilot channel within the Upcoming transmitted half-frames is or not. The use of the FAC bit improves the C / I estimate by the mobile devices <figref>6</figref> and Therefore the request of the data rate, since, by sending (broadcast) of knowledge of the interference activity. In the exemplary embodiment changes the FAC bit successive only limits of half-frames and in 8 Time-slots repeated, resulting in a bit rate of 75 bps. The parameter for the FAC bit is listed in Table 4 below.

By Using the FAC bits can the mobile devices <figref>6</figref> the calculate C / I measurement as follows: <img img-content="mf" img-format="tif" he="21" wi="125" file="00590001.tif" />in which (C / I)_i the C / I measurement of the i^th forward signal is C_i the total received power the i^th Forward link signal, C_j the received power of the j^th Forward link signal is, I is the total interference if all base stations <figref>4</figref> Send, α_j the FAC bit of the j^th Forward link signal, which may be 0 or 1, depending of the FAC bit.

XII. Reverse link Datentübertragung

In of the present invention supports the reverse link data transmission variable rate. The variable rate provides flexibility and allows it to mobile devices <figref>6</figref>. with a send several data rates, depending on the amount of to the base station <figref>4</figref> to be transmitted Data. In the exemplary embodiment, mobile station<figref>6</figref> data any time transmitted with the lowest data rate. In the exemplary embodiment requires data transmission with higher Data rates an approval by the base station <figref>4</figref>, The Implementation minimizes transmission delay on the rear forward link, while it efficient utilization of the reverse link resources guaranteed.

A exemplary illustration of the flow diagram of the data transmission on the reverse link the present invention is in <figref idrefs="S93">8</figref> shown. Initially, at slot n, leads , mobile station <figref>6</figref> an access attempt (Access test) from, as in the US patent mentioned above no. 5,289,527 described to the data channel with the lowest rate across the reverse link at block <figref>802</figref> build. In the same slot n demodulates the base station <figref>4</figref> the access signal (access probe) and receives the access message at block <figref>804</figref>, The base station<figref>4</figref> approved the request for the data channel and, at slot n + 2, transmits the authorization and assigned RPC index on the control channel, at block <figref>806</figref>, At slot n + 2 receives , mobile station <figref>6</figref> the Approval and, at block <figref>808</figref> by the base station <figref>4</figref> power controlled. Beginning at slot n + 3 will start the mobile device <figref>6</figref> the transfer the pilot signal and has immediate access to the data channel with the lowest data rate on the reverse link.

If the mobile radio device <figref>6</figref> traffic data present and it is requesting a data channel at a high rate, , mobile station <figref>6</figref> the Request at block <figref>810</figref> start. At slot n + 3 receives the base station <figref>4</figref> the request for high-speed data, at block <figref>812</figref>, At slot n + 5, the base station<figref>4</figref> the Approval on the control channel, at block <figref>814</figref>, In slot n + 5 receives , mobile station <figref>6</figref> approval at block <figref>816</figref> and starts data transmission at high speed on the reverse link, starting at n + 6 slot at block <figref>818</figref>,

XIII. Reverse Link Architecture

In the data communication system of the present invention differs a transmission over the reverse link of the transmission via the forward link in several respects. On the forward link data transmission occurs typically from a base station <figref>4</figref> to a mobile station <figref>6</figref>, About the reverse link , each base station <figref>4</figref> However, at the same time data transfers of several mobile telephones <figref>6</figref> receive. In the exemplary embodiment, , any mobile device <figref>6</figref> With a sending of several data rates, depending on the amount of to base station <figref>4</figref> data to be transmitted. This System design reflects the asymmetric characteristic of data communication.

In the exemplary embodiment, is the time base unit on the reverse link to identical the time base unit on the forward link. In the exemplary embodiment carried forward&lt;?page 27?&gt;connectionless and reverse link data transmissions over time slots with a duration of 1.667 ms. Since data transmission on the reverse link however, typically occurs at a lower data rate, a longer Time base unit can be used to improve efficiency.

In the exemplary embodiment, supports the reverse link two channels: the pilot / DRC channel and the data channel. The function and implementation of each of these channels are described below. The pilot / DRC channel is used to the pilot signal and to transmit the DRC messages and the data channel is used to transmit traffic data.

On Diagram of the exemplary reverse link frame structure of the present Invention is in <figref idrefs="S91">7A</figref> shown. In the exemplary embodiment is the frame structure of the reverse link similar to the Frame structure of the Forward link, in the <figref idrefs="S84">4A</figref> is shown. However, be on the reverse link the pilot / DRC data and traffic data simultaneously on the inphase transmitted and quadrature channels.

In the exemplary embodiment, the mobile station transmits <figref>6</figref> a DRC message on The pilot / DRC channel at each time slot whenever mobile station <figref>6</figref> data transmission receives a high speed. Alternatively, if the mobile station <figref>6</figref> no data transmission receive at a high speed, the entire slot on may the pilot / DRC channel containing the pilot signal. The pilot signal is by the receiving base station for a number of functions used: as an aid to initial set-up, as a phase reference for the Pilot / DRC and the data channels and as a source of the reverse link power control closed-loop.

In the exemplary embodiment, is the bandwidth of the reverse link as 1.2288 MHz selected. This bandwidth selection allows the use of existing hardware, the for a CDMA system has been developed that corresponds to the IS-95 standard. However, other bandwidths can be used to increase capacity and / or to meet system requirements. In the exemplary embodiment, are the same long PN code and the short PN₁- and PN_QCodes used, as in the IS-95 standard specified to the reverse link signal to spread. In the exemplary embodiment, the reverse link channels are transmitted using the QPSK modulation. Alternatively can be used OQPSK modulation, the peak-to-average amplitude variation the modulated signal to minimize what improved in a may result performance. The use of different system bandwidth, different PN codes and modulation schemes can be considered are drawn and is within the scope of the present Invention.

In the exemplary embodiment, The transmit power of the transmissions over the reverse link controlled on the pilot / DRC channel and the data channel so that the e_b/ I_O the reverse link signal, as at the base station <figref>4</figref> is measured at a predetermined e_b/ I_O-Setpoint is maintained, such as in U.S. Patent No. aforementioned. 5,506,109 discussed. The power control by the base station<figref>4</figref> in Communication with the mobile station <figref>6</figref> retained, and the commands are transmitted, as discussed above as the RPC bits.

XIV. Reverse link data channel

On Block diagram of the exemplary reverse link architecture the present invention is in <figref idrefs="S90">6</figref> shown. The data is divided into data packets and an encoder <figref>612</figref> provided. For each Data packet generates the encoder <figref>612</figref> the CRC parity bits, adds the Code tail bits, and encodes the data. In the exemplary embodiment encodes the encoder <figref>612</figref> the packet in accordance with the encoding format, the in the aforementioned US Patent Application No. Is 08 / 743.688 disclose. Other encoding formats can also be used and are within the scope of the present Invention. The encoded packet from encoder<figref>112</figref> becomes the block interleaver <figref>614</figref> Provided that the code symbols rearranges in the package. The interleaved packet is the multiplier<figref>616</figref> provided, which encodes the data with the Walsh code and the encoded data a reinforcing element <figref>618</figref> provides. The reinforcing element <figref>618</figref> scaled the data to maintain a constant energy-per-bit E_b maintain, independently of the data rate. The scaled data from gain element<figref>618</figref> will multipliers <figref>650b</figref> and <figref>650d</figref> provided, which spread the data with the PN_I PN_Q- or sequences. The spread Data from the multipliers <figref>652b</figref> and <figref>650d</figref> will Filter <figref>652b</figref> or. <figref>652d</figref> provided that filter the data. The filtered data from filters<figref>652a</figref> and <figref>652b</figref> will the adder <figref>654a</figref> provided, and the filtered signals from the filters <figref>652c</figref> and <figref>652d</figref> be the adder <figref>654b</figref> provided. adders <figref>654</figref> add the signals of the data channel to the signals from the pilot / DRC channel. The outputs of the adders<figref>654a</figref> and &lt;?page 28?&gt;<figref>654b</figref> include IOUT or Q OUT, with the in-phase sinusoid COS (w_ct) and the quadrature sinusoid SIN (w_ct) are modulated (as in the forward link) and are added (not in <figref idrefs="S90">6</figref> shown). In the exemplary embodiment, transmitting the traffic data on both the inphase and on the quadrature phase of the sinusoid.

In the exemplary embodiment, the data is spread with the long PN code and the short PN codes. encrypted The long PN code the data so that the receiving base station <figref>4</figref> in the Location is the sending mobile device <figref>6</figref> to identify. The short PN code spreads the signal over the entire system bandwidth. The long PN sequence is determined by the long code generator <figref>642</figref> generated and the multipliers <figref>646</figref> provided. The short PN₁- And PN_Qsequences be by the short code generator <figref>644</figref> created and also multipliers <figref>646a</figref> or. <figref>646b</figref> provided, which multiply the two sets of sequences to the PN_I or to form PN_Q signals. The time / control circuit<figref>640</figref> provides the time reference provided.

the exemplary block diagram of the data channel architecture as shown in <figref idrefs="S90">6</figref> shown, is one of countless architectures, the data coding and modulation on the reverse link support. For data transmission high rate may be similar to the forward link and an architecture be used which uses a plurality of orthogonal channels. Other architectures such as the architecture for the traffic channel over the reverse link in the CDMA system, which corresponds to the IS-95 standard, can also contemplated be and is within the scope of the present invention.

In the exemplary embodiment, supports the reverse link data channel four data rates, which are tabulated in Table 5 below. Additional data rates and / or Other data rates may get supported and are within the scope of the present invention. In the exemplary embodiment depends on the Packet size for the reverse link from when the data rate, as shown in Table 5 below. As in the previously mentioned US patent application Ser. No. 08 / 743.688, a improved decoder performance for obtain larger packet sizes will. Therefore, other packet sizes than listed in Table 5 be used to improve performance and are within the scope of the present invention. In addition, the packet size can be a Parameters are made, are independent of the data rate. table 5 - pilot and power control modulation parameters <img img-content="tb" img-format="tif" he="63" wi="143" file="00650001.tif" />

As shown in Table 5, supported the reverse link a plurality of data rates. In the exemplary embodiment, is the lowest data rate of 9.6 Kbps to each mobile station <figref>6</figref> after Registering with the base station <figref>4</figref> assigned. In the exemplary embodiment can the mobile devices <figref>6</figref> Data about the Send data channel with the lowest rate in each time slot, without a permit from the base station <figref>4</figref> request. In the exemplary embodiment, is data transmission with higher Data rates through the selected base station <figref>4</figref> approved, based on a set of System parameters such as system load, fairness and overall Throughput. An exemplary scheduling mechanism for data transmission at high speed in the aforementioned US Patent Application Ser. No. 08 / 798.951 described in detail.

&lt;?page 29?&gt;

XV. Reverse Link Pilot / DRC Channel

the exemplary block diagram of the pilot / DRC channel is in <figref idrefs="S90">6</figref> shown. The DRC message is the DRC encoder <figref>626</figref> provided, Message in accordance the encoded with a predetermined encoding format. Encoding the DRC message is important since the error probability of the DRC message sufficiently must be low because an incorrect determination of the data rate of forward link the system throughput affected. In the exemplary embodiment, the DRC encoder <figref>626</figref> a CRC block encoder with a rate (<figref>8</figref>. <figref>4</figref>), Which in the 3-bit DRC message a 8-bit code word coded. The encoded DRC message is a multiplier<figref>628</figref> provided, encoding the message with the Walsh code, the target base station <figref>4</figref>. to which the DRC message is directed, clearly identified. The Walsh code is a Walsh generator <figref>624</figref> provided. The encoded DRC message is provided to a multiplexer (MUX) <figref>630</figref> provided for multiplexing the message with the pilot data. The DRC message and the pilot data are multipliers <figref>650a</figref> and <figref>650c</figref> provided, which spread the data with the PN_I and PN_Q signals. That's why are the pilot and the DRC message on both the inphase and transmitted to the quadrature phase of the sine.

In the exemplary embodiment, the DRC message to the selected base station <figref>4</figref> transfer. This is achieved by encoding the DRC message with the Walsh code that selected base station <figref>4</figref> identified. In the exemplary embodiment, has the Walsh code length of 128 chips. The derivation of Walsh codes of 128 chips is Prior known art. A unique Walsh code is any base station <figref>4</figref> assigned with in communication the mobile radio device <figref>6</figref> is. Each base station <figref>4</figref> decodes the signal on the DRC channel with the assigned Walsh code. The selected base station<figref>4</figref> is able to decode the DRC message and transmits data to the requesting mobile device <figref>6</figref> on the forward link in response thereto. Other base stations<figref>4</figref> are Location festzustel len that the requested data rate is not on it is addressed because these base stations <figref>4</figref> other Walsh codes assigned.

In the exemplary embodiment, are the short PN codes of the reverse link for all base stations <figref>4</figref> in the data communication system, the same, and there is no offset in the short PN sequences to the different base stations <figref>4</figref> to differ. The data communication system of the present invention supports Soft handoff via the reverse link. A use of the same short PN codes with no offset allows a plurality of base stations <figref>4</figref>, The same transmission over the reverse link from the mobile unit <figref>6</figref> during a Soft handoffs receive. The short PN codes provide a spectral spread, but do not allow identification of the base stations <figref>4</figref>,

In the exemplary embodiment, wears DRC message from the mobile device <figref>6</figref> requested Data rate. In the alternative embodiment, the DRC message carries an indication of the quality of the forward link (Eg. As the C / I information by mobile station <figref>6</figref> measured has been). Mobile station<figref>6</figref> can simultaneously, the pilot signals of the forward link of one or a plurality of base stations <figref>4</figref> received and performs the C / I measurement on each received pilot signal. Mobile station<figref>6</figref> then selects the best base station <figref>4</figref>, Based on a set of Parameters, the current and previous C / I measurements may include. The rate control information is in the DRC message formatted, the to the base station <figref>4</figref> in one or more transmitted embodiments can be.

In of the first embodiment transmits the mobile station <figref>6</figref> a DRC message based on the requested data rate. The requested data rate is the highest Compatible Data rate which yields satisfactory performance at the C / I, the by mobile station <figref>6</figref> measured has been. From the C / I measurement is calculated, mobile station<figref>6</figref> first the maximum data rate that yields a satis tory performance. The maximum data rate is then added to one of the supported data rates quantized and designated as the requested data rate. The data rate index, corresponding to the requested data rate is transmitted to the selected base station <figref>4</figref> transfer. An exemplary set of supported data rates and the corresponding Data rate indices are shown in Table 1 below.

In the second embodiment, in the mobile station <figref>6</figref> a Indication of the quality the forward link to the selected base station <figref>4</figref> sends the mobile station transmits <figref>6</figref> a C / I index which represents the quantized value of the C / I measurement. The C / I measurement can be mapped to a table and a C / I index be assigned. A use of more bits to represent of the C / I index allows a finer quantization of the C / I measurement. Likewise, the picture may be linear or vordeformiert (predistorted) be. For a linear mapping, each increment in the C / I index a corresponding increase the C / I measurement. For example, each step in the C / I index a 2.0 dB increase is in the C / I measurement&lt;?page 30?&gt;put. For a vordeformierte illustration can each increment of the C / I index another increase represent the C / I measurement. For example, a vordeformierte Figure used to quantize the C / I measurement, for equalizing on the cumulative distribution function curve (cumulative distribution function, CDF) of in <figref idrefs="S95">10</figref> shown C / I distribution.

Other embodiments for transmitting the rate control information from the mobile device <figref>6</figref> to base station <figref>4</figref> can in Are contemplated and are within the scope of the present invention. Furthermore, the use of another number of bits is for displaying the rate control information also within the scope of the present Invention. In a large Part of the specification, the present invention of simplicity half are described in the context of the first embodiment, namely the Use the DRC message to convey the requested data rate.

In the exemplary embodiment, , the C / I measurement on the pilot signal of forward link carried out in a manner are, which is the similar to that used in a CDMA system. A method and apparatus for performing the C / I measurement is disclosed in U.S. patent application Ser. No. 08 / 722.763, entitled "METHOD AND APPARATUS FOR MEASURING LINK QUALITY IN A SPREAD SPECTRUM COMMUNICATION SYSTEM "filed, on 27 September 1996 and the holder of the present invention assigned. In summary, the C / I measurement on the pilot signal be obtained by despreading the received signal with the short PN codes. The C / I measurement and the pilot signal can contain inaccuracies if the channel conditions between the time of the C / I measurement and the time of actual data transmission changed have. In the present invention allows the use of the FAC bits to mobile devices <figref>6</figref>. to account for the forward link activity, when determining the requested data rate.

In the alternative embodiment , the C / I measurement on the traffic channel of the forward link accomplished will. The traffic channel signal is first with the long PN code and the short PN code despread and decoded with the Walsh code. The C / I measurement on the signals on the data channels can be more accurate because a larger percentage the transmit power for data transmission is assigned. Other methods to measure the C / I of the forward link signal by mobile station <figref>6</figref> can also are contemplated and are within the scope of present invention.

In the present embodiment, the DRC message transmitted in the first half of the time slot (please refer <figref idrefs="S91">7A</figref>). For an exemplary time slot of 1.667 ms includes the DRC message, the first 1024 chips or 0.83 msec of the time slot. The remaining 1024 chips of time be by the base station <figref>4</figref> used to the message to demodulate and decode. The transmission of the DRC message in previous Part of the time slot allows the Ba sisstation <figref>4</figref>, the to decode the DRC message within the same time slot and possibly Data at the requested data rate in the immediately subsequent transmit timeslot. The short processing delay it allows the communication system of the present invention, adapt quickly to changes adjust in the operating environment.

In the alternative embodiment is the requested data rate of the base station <figref>4</figref> by received the use of an absolute reference and a relative reference. In this embodiment, is the absolute reference comprising the requested data rate, transmitted periodically. The absolute reference allows the base station <figref>4</figref>, the exact data rate by mobile station <figref>6</figref> was requested, to determine. For each time slot between transmissions the absolute references transmits the mobile station <figref>6</figref> a relative reference to base station <figref>4</figref>, Which indicates whether the requested data rate for the upcoming time slot is higher, lower or the same as the requested data rate for the previous time slot is. Periodically transmits the mobile station<figref>6</figref> a absolute reference. Periodic transmission of the data rate index allows that the requested data rate to a known State is set and ensures that erroneous receptions of relative references do not accumulate. The use of absolute References and relative references can at the transmission rate of the DRC messages the base station <figref>6</figref> reduce. Other protocols for transferring the requested data rate can are also contemplated and are within the scope of the present invention.

XVI. Reverse Link Access Channel

Of the Access channel by mobile station <figref>6</figref> for transferring messages to the base station <figref>4</figref> during the registration phase used. In the exemplary embodiment, the access channel implemented using a slotted structure, wherein on each slot at random funk by the mobile&lt;?page 31?&gt;device <figref>6</figref> accessed is. In the exemplary embodiment, is the access channel to the DRC channel time-bundled (time multiplexed).

In the exemplary embodiment, transmits the access channel Messages in access channel capsules. In the exemplary embodiment, is the frame format the access channel the same as specified by the IS-95 standard, except that the measure of time in Frames of 26.67 ms is, instead, of frames of 20 ms as in IS-95 standard specifies. The diagram of an exemplary Access channel capsule is in <figref idrefs="S92">7B</figref> shown. In the exemplary embodiment, , each access channel capsule <figref>712</figref> a preamble <figref>722</figref>. one or more messages capsules <figref>724</figref> and padding bits <figref>726</figref>, Each message capsule <figref>724</figref> includes a message length field (MSG LEN) <figref>732</figref>, A message body <figref>734</figref> and CRC parity bits <figref>736</figref>,

XVII. Reverse Link NACK Channel

In of the present invention transmits the mobile station <figref>6</figref> the NACK messages on the data channel. The NACK message is generated for each packet that flawed by mobile station <figref>6</figref> was received. In the exemplary embodiment, can the NACK messages using the blank-and-burst signaling data format be used, which in the aforementioned US Pat. No. 5,504,773 disclosed.

Although described the present invention in the context of a NACK protocol, was the use of an ACK protocol can be contemplated be and is within the scope of the present invention.