Resource assignment in an enhanced uplink mobile communication system

The present invention relates to signaling in a cellular communication system, but not exclusively, but particularly to signaling an acquisition signal in a cellular communication system of 3GPP (3rd Generation Partnership Procect).

Currently, third-generation cellular communication systems are being deployed to further expand the communication services provided to mobile users. The most widely adopted 3rd generation communication systems are based on CDMA (Code Division Multiple Access) and FDD (Frequency Division Duplex) or TDD (Time Division Duplex). In CDMA systems, user isolation is obtained by assigning different spread and / or scrambled codes to different users at the same carrier frequency and at the same time interval. User separation of TDMA (time division multiple access) is realized by allocating different time slots to different users. In addition to TDMA, TDD provides the same carrier frequency used for both uplink and downlink transmissions. An example of a communication system using this principle is UMTS (Universal Mobile Telecommunication System). CDMA, especially UMTS WCDMA (Wideband) A further description of CDMA) mode can be found in'WCDMA for UMTS', Harri Holma (edit), Antti Toskala (edit), Wiley & Sons, 2001, ISBN 0471486876.

To provide extended communication services, 3rd generation cellular communication systems are designed to support a variety of different services, including packet data communication. Similarly, existing second-generation cellular communication systems such as GSM (Global System for Mobile communications) have been extended to support a larger number of different services. One such extension is GPRS (General Packet Radio System), which is a system developed to enable packet data communication in GSM communication systems. Packet data communication is particularly suitable for data services with dynamically changing communication requirements, such as Internet access services.

In cellular mobile communication systems with non-constant data rates of traffic and services, it is efficient to dynamically share radio resources among users according to the needs at a particular point in time. This is in contrast to services with constant data rates, where services with constant data rates can be allocated radio resources appropriate for the service data rate over a long period of time, such as call duration.

Under the current UMTS TDD standard, uplink shared radio resources can be dynamically allocated (scheduled) by the RNC (Radio Network Controller) scheduler. However, in order to operate efficiently, the scheduler needs to recognize the amount of uplink data waiting for uplink transmission by each mobile user. This allows the scheduler to allocate resources to the users who need it most. In particular, it avoids wasting resources by being assigned to a mobile station that does not have the data to transmit.

In recent years, considerable efforts have been invested in particularly improving the uplink performance of 3GPP systems. One way to do this is to move the scheduling entity from the RNC to the radio base station so that transmission and retransmission latency can be reduced. As a result, fairly fast and efficient scheduling can be achieved. This, in turn, increases the perceived end-user throughput. In such an implementation, the scheduler at the base station (rather than the RNC) assumes control over the authorization of uplink resources. Fast scheduling responses to user traffic needs and channel conditions are desirable in improving scheduling efficiency and transmission delays for individual wireless subscriber communication units.

In particular, in order to achieve efficient communication of data bits through wireless interface resources, the retransmission of inaccurately received data packets is specified in most 3GPP packet data services. Data retransmission is normal in such systems. In order to iteratively improve the probability that retransmissions decode the data accurately, a so-called hybrid scheme may be used in which signals and retransmissions from previous transmissions of the same data at the receiver are accumulated. Optimal link efficiency (in terms of energy required per error-free transmit bit following retransmission) is achieved when the probability of error in the first transmission is relatively high (eg 10% -50%). Therefore, hybrid and high-speed retransmission methods are typically used. However, the radio interface transmission delay associated with retransmission is very high. The reason for this is that there is a delay in the feedback processing of the reception confirmation (for example, a delay in waiting for a possible reception confirmation before deciding to retransmit) and a delay in scheduling the retransmit data packet.

For uplink multiplex access, the FDD and TDD physical layers use chip scrambling behavior following spreading (using one or more of the so-called sets of channelization codes). In the FDD uplink, each user is assigned a user-specific sequence for scrambling. The user-specific sequence allows the separation of individual user signals at the base station receiver, as well as the spread of channelization codes. Conversely, in TDD, all users in a given cell use the same scramble code. Therefore, users of TDDs using the same time slot can be separated primarily by having different physical channelization codes.

The result of this difference in uplink scramble code allocation between FDD and TDD modes must be that a finite set of channelization code resources must be shared among competing users belonging to the same TDD cell. However, FDD allows users in the same cell to use the same channelization code according to some constraints on the number of codes used and the spread rate.

For the 3GPP enhanced uplink system, the user's uplink transmission is scheduled by the base station. A low latency retransmission method is supported in which the base station returns a fast reception confirmation indicator for the transmit bit of a particular block to the wireless subscriber communication unit. If the transmission of the data block is received incorrectly, the indicator will be set to'NACK'by the base station, and upon receipt of the transmitted indicator, the wireless subscriber communication unit will retransmit the data. Recognize that there is. If the transmission of the data block is received correctly, the indicator is set to'ACK'by the base station, and upon reception, the wireless subscriber communication unit receives the data accurately and is done by the base station. Recognize that new data can be selected for transmission with the next scheduling permission.

The channel used to transmit ACK / NACK from the base station to the wireless subscriber communication unit is called E-HICH (Enhanced Uplink Hybrid ARQ Indicator Channel). This channel is inevitably a low data rate channel because it conveys only one bit of information for each currently active user. With the FDD extended link, if the wireless subscriber communication unit is not active at a particular point in time, there is no need to send a receipt confirmation and no receipt confirmation is sent (the wireless subscriber communication unit does not expect to receive a receipt confirmation). ..

In FDD, the way the receipt confirmation indicator is encoded in the E-HICH channel is by assigning a user-specific series of length '40' to each user who uses the extended uplink service of the cell. .. In particular, the sequence is assigned for the duration of the extended uplink'call'. During a quiet period between bursts of uplink transmission, the code remains assigned to a particular user and is not reusable by other users. This limits the size of the possible population of active users to 40 per E-HICH. Each FDD E-HICH uses a channelization code with a spread of 128, which consumes 1/128 of the available downlink code resources (Note: unlike uplink, scrambled code is FDD downlink. Cell-specific in the link direction). When the population or users exceed 40, additional E-HICH must be configured, thus consuming 1/128 of the available downlink code resources, and so on.

A further problem that exacerbates the efficient use of valuable resources is the "always on" that users can be kept active recently (without having to reconfigure communication state and suffer the associated transmission latency disadvantages). , Ready to send or receive communications from the Internet). In a wireless mobile communication system, in this "ready" state, it is imperative that the user consume as little system resources as possible when no actual data traffic is being transmitted or received. This makes it possible to maximize the number of users who can be ready at some time.

In the FDD extended uplink system, each user inconveniently consumes valuable downlink code resources when the user is in this "ready" state. The reason for this is that a user-specific sequence is assigned and reserved to send a receipt confirmation indicator when the need arises.

Therefore, current signaling techniques are suboptimal. For example, if only a few users are actively sending uplink data at any given time and the remaining users are inactive, then going down to each user (regardless of operating state) for the purpose of acknowledgment signaling. Any long-term allocation of link code resources wastes system resources.

Therefore, improved signaling in cellular communication systems is advantageous. In particular, a system that enables the provision of improved reception confirmation processing is advantageous.

<p> Therefore, the present invention preferably aims to alleviate, alleviate or eliminate one or more of the above-mentioned drawbacks alone or in some combination.</p>

<p> According to a first aspect of the present invention, there is provided a device such as a base station that transmits signaling information in a cellular communication system that supports a plurality of shared uplink transmit resources that are divided into sets of mutually exclusive transmit resources. Will be done. The device has means to authorize the uplink transmit resource to the wireless subscriber communication unit via the uplink transmit authorization message. This device provides means for receiving uplink transmissions from the wireless subscriber communication unit, means for deriving uplink code resource identifiers associated with uplink transmissions or authorization messages, and downlinks associated with the derived uplink code resource identifiers. It has means for assigning at least one downlink code sequence used for transmitting link signaling information, and means for transmitting downlink transmission having at least one downlink code sequence to the wireless subscriber communication unit.</p><p> Shared resources may be defined with respect to the code (the CDMA code of the CDMA system or the time frequency code of other multiple access systems) and the time slot. In one embodiment, the system also supports multiple downlink shared resources that are divided into sets of mutually exclusive transmit resources. As with uplinks, shared downlink resources may be defined with respect to the code (CDMA code of the CDMA system or the time frequency code of other multiple access systems) and the time slot.</p><p> INDUSTRIAL APPLICABILITY According to the present invention, it may be possible to improve the use of communication resources in a communication system. INDUSTRIAL APPLICABILITY According to the present invention, it may be possible to improve the performance recognized by the end user. The present invention may provide increased capacity, reduced delay, and / or increased effective throughput.</p><p> The present invention may also support low latency retransmission schemes. In particular, the present invention may allow a'always on'Internet connection in a TDD system. The present invention may facilitate communication channels that support a large number of users in the'ready'state. The present invention can also avoid the need for long-term code reservations for a particular user.</p><p> The present invention may allow a communication system to reuse resources that are not currently in use for other purposes or for other users. The present invention can reduce code resource management problems as the size of a population of active users in a cell increases. The present invention can avoid the need for higher layers of the communication protocol stack to allocate E-HICH sequences. The present invention may be compatible with any existing communication system, such as a 3GPP TD-CDMA cellular communication system.</p><p> According to the optional feature of the present invention, the means for assigning at least one downlink code sequence associates a reception confirmation signal with the uplink code resource identifier, whereby the means for transmitting is the derived uplink code resource. It has to transmit a downlink transmission having a reception confirmation signal associated with an identifier to a wireless subscriber communication unit.</p><p> This can improve communication, and can enable efficient use of code resources during packet data transmission, especially for improved acknowledgment (ACK) / negative response (NACK) processing.</p><p> According to the optional feature of the present invention, the association of the receipt confirmation signal with the derived uplink code resource identifier may be used in a TDD 3GPP system. According to a further optional feature of the present invention, the derivation of the uplink code resource identifier is used in some frequency division duplex (FDD) system where the uplink code resource is finite / limited. You may.</p><p> According to the optional feature of the present invention, the receipt confirmation signal may be used in the extended uplink hybrid automatic repeat request (ARQ) indicator channel (E-EICH) of a 3GPP system. The present invention can reduce the number of users who unnecessarily consume downlink transmission resources (eg, E-HICH) when they are not actively participating in uplink transmission.</p><p> According to the optional feature of the present invention, the receiving means includes means for receiving the uplink transmission previously scheduled by the base station. For example, the receipt confirmation signal may be associated with a base station resource authorization message. This allows one of the downlink'permission'channels used to allocate resources to wireless subscriber communication units and the corresponding downlink channels used to propagate the ACK / NACK corresponding to the authorized resource. One-to-one mapping may be possible.</p><p> According to the optional feature of the present invention, multiple reception confirmation signals are in a single minimum transmission unit of Time Division Duplex (TDD) Code Division Multiple Access (CDMA). It may be time or code division multiple access. Typically, in a 3GPP TDD system, the minimum transmission unit has a single code with a spread of 16 in a single time slot.</p><p> According to the optional feature of the present invention, the means for assigning at least one downlink code sequence used to convey the downlink signaling information associated with the derived uplink code resource identifier are substantially each. Has to associate a tag or identifier with the actively transmitting user of. This takes advantage of the fact that resource allocations typically given to each user do not overlap (eg for 3GPP systems). Therefore, in this way, it can be ensured that the resource tag or identifier does not overlap. Advantageously, this provides additional assurance that a unique downlink E-HICH sequence will be assigned to each active user.</p><p> This allows for more efficient communication, for example, better use of sources that are now available, which facilitates dynamic systems when telecommunications equipment shares resources. To do.</p><p> According to the optional feature of the present invention, tags may be substantially associated with each actively transmitting user, and transmissions are performed at a single transmit time interval (TTI). To. According to the optional feature of the present invention, the tag identifies a resource unit extending to both the uplink portion and the downlink portion of the communication frame. This can allow the association between the resource tag and the actual physical resource to be unaffected by a particular frame configuration or any uplink or physical link split point.</p><p> According to the optional feature of the present invention, the transmitting user can be assigned a resource unit from, for example, a '240' orthogonal sequence of 3GPP TDD operation. This can reduce the waste of the payload. This may allow flexible selection of the orthogonal code set of the E-HICH series used to convey the receipt confirmation indicator.</p><p> According to the optional feature of the present invention, a plurality of users can be assigned a long downlink code sequence configured by using at least two steps of continuous spreading processing using at least two short code sequences. This can reduce the complexity of the wireless subscriber communication unit and its memory requirements. This can also allow flexible selection of orthogonal code sets.</p><p> According to the optional features of the present invention, the present invention may provide system performance that is particularly advantageous for uplink packet data communication services, which may be uplink packet data communication services in particular.</p><p> According to a second aspect of the present invention, there is provided a wireless subscriber communication unit that receives signaling information in a cellular communication system that supports a plurality of shared uplink transmit resources that are divided into sets of mutually exclusive transmit resources. To. The wireless subscriber communication unit has a means of receiving a downlink transmission from a base station, whereby the downlink transmission is associated with a derived uplink code resource identifier for the previous uplink transmission or previous authorization message. Has at least one downlink code sequence used to convey downlink signaling information.</p><p> According to a third aspect of the present invention, there is provided a method of transmitting signaling information in a cellular communication system that supports a plurality of shared uplink transmit resources divided into a set of mutually exclusive transmit resources. This method includes a step of allowing the wireless subscriber communication unit to transmit uplink resources via an authorization message, a step of receiving an uplink transmission from the wireless subscriber communication unit, and an uplink code from the uplink transmission or authorization message. A step to derive the resource identifier, a step to assign at least one downlink code sequence used to convey the downlink signaling information associated with the derived uplink code resource identifier, and at least one downlink code sequence. It has a step of transmitting the downlink transmission to the wireless subscriber communication unit.</p><p> According to a fourth aspect of the present invention, there is provided a method of receiving signaling information in a cellular communication system that supports a plurality of shared uplink transmit resources divided into sets of mutually exclusive transmit resources. This method comprises the step of receiving a downlink transmission from a base station, whereby the downlink transmission is associated with a derived uplink code resource identifier for the previous uplink transmission or previous authorization message. It has at least one downlink code sequence used to convey signaling information.</p><p> According to a fifth aspect of the present invention, a plurality of shared uplink transmission resources divided into a set of mutually exclusive transmission resources are supported, and downlink transmission from a base station to a wireless subscriber communication unit is supported. A cellular communication system adapted as described above is provided, whereby the downlink transmission has at least one downlink code sequence associated with the derived uplink code resource identifier for the previous uplink transmission or previous authorization message. Have.</p><p> According to the optional feature of the present invention, the cellular communication system is a 3GPP (3rd Generation Partnership Project) system. The 3GPP system may be, in particular, a UMTS cellular communication system. Therefore, according to the present invention, it may be possible to improve the performance of the 3GPP cellular communication system.</p><p> The present invention can enable improved performance in TDD cellular communication systems, and in particular can improve the use of 3GPP extended uplink systems.</p><p> According to a sixth aspect of the present invention, a wireless communication protocol is provided that supports downlink transmission from a base station to a wireless subscriber communication unit, whereby downlink transmission is a previous uplink transmission or a previous uplink transmission. It has at least one downlink code sequence associated with the derived uplink code resource identifier for the authorization message.</p><p> The optional features, comments and / or advantages described above with reference to a device such as a base station transmitting uplink signaling information also apply to the method of transmitting uplink signaling information, and the optional features are , It can be seen that it can also be included in a method of transmitting uplink signaling information individually or in some combination.</p><p> The optional features, comments and / or advantages described above with reference to the wireless subscriber communication unit that receives the downlink signaling information also apply to the method of receiving the downlink signaling information, and the optional features are: It can be seen that it can also be included in a method of receiving downlink signaling information individually or in some combination.</p>

The above and other aspects, features and advantages of the present invention will become apparent from the examples described below and will be described with reference to the examples.

Examples of the present invention will be described as only one example with reference to the accompanying drawings.

The following detailed description focuses on embodiments of the present invention applicable to UMTS (Universal Mobile Telecommunication System) cellular communication systems and in particular UTRAN (UMTS Terrestrial Radio Access Network) operating in TDD (Time Division Duplex) mode. .. However, it can be seen that the present invention is not limited to this particular cellular communication system and can be applied to other cellular communication systems. In this regard, in one embodiment of the invention, the cellular communication system supports a plurality of shared uplink transmit resources that are divided into sets of mutually exclusive transmit resources.

FIG. 1 shows an example of a cellular communication system 100 in which an embodiment of the present invention can be used. In one embodiment of the invention, the cellular communication system 100 supports a plurality of shared uplink transmit resources that are divided into sets of mutually exclusive transmit resources. The shared uplink transmit resource may be defined in terms of code and time slot. In this regard, the code may represent a CDMA spread or scrambled sequence, or a common time frequency code in a time / frequency division multiplexing system. Due to the finite number of codes and time slots, any one unit in the total shared resource space is defined by the time slot / code coordinate pair. These individual non-overlapping units of shared resources may be further grouped to form larger units of allocatable resources.

In the cellular communication system 100, the geographical area is divided into a plurality of cells each serviced by the base station 105. Base stations (also referred to as Node B in some cases) are interconnected by a fixed network capable of communicating data between and from the base station and the core network 109. The wireless subscriber units 101 and 103 are serviced via a wireless communication link with the base station 105 of the cell in which the wireless subscriber communication unit is located. Wireless subscriber communication units are often referred to as mobile stations (MS) or user equipment (UE), which are considered interchangeable terms.

For example, the wireless subscriber communication unit may be a remote unit, a mobile station, a communication terminal, a personal digital assistant, a laptop computer, an embedded communication processor, or any communication element that communicates with the wireless interface of the cellular communication system 100.

When the wireless subscriber units 101, 103 move, they move from the communication service area supported by one base station 105 to the service area supported by another base station (ie, from one cell to another). There is. As mobile stations 101 and 103 approach base station 105, they enter the area of overlapping service areas of the two base stations and within this overlapping range change to be supported by the new base station. As the mobile station moves further into the new cell, it will continue to be supported by the new base station. This is known as mobile station handover or handover between cells.

A typical cellular communication system typically extends the service area nationwide and has hundreds or thousands of cells supporting thousands or millions of mobile stations. Communication from a mobile station to a base station is known as an uplink, and communication from a base station to a mobile station is known as a downlink.

The base station 105 is coupled to a radio network controller (RNC) 107. The RNC107 performs a number of control functions for the radio interface, including radio resource management and relaying data to and from the appropriate base station.

RNC107 is coupled to core network 109. The core network can interconnect RNCs and operate to relay data between any two RNCs. As a result, the wireless subscriber communication unit of the cell can communicate with the wireless subscriber communication unit of another cell. Further, the core network 109 has a gateway function for interconnecting to an external network such as a PSTN (Public Switched Telephone Network). As a result, the wireless subscriber communication unit can communicate with the land line telephone and other communication terminals connected by the land line. Further, the core network 109 has most of the functions necessary for managing a normal cellular communication network, including a function of relaying data, permission control, resource allocation, subscriber billing, mobile station authentication, and the like.

For clarity and brevity, only certain elements of the cellular communication system 100 necessary for the description of some embodiments of the present invention are illustrated, the cellular communication system 100 with other base stations and RNCs. It can be seen that it may have many other elements, including other network entities such as SGSN, GGSN (GPRS Gateway support Node), HLR (home location register), VLR (visitor location register), etc.

Normally, data scheduling on the wireless interface is performed by the RNC107. However, recently, packet data services have been proposed that try to take advantage of fluctuating channel conditions when scheduling data on shared channels. Specifically, HSDPA (High Speed Downlink Packet Access) is currently standardized by 3GPP. HDDPA allows scheduling to take into account the downlink status of individual UEs. Therefore, UE data may be scheduled when channel propagation is enabled with low downlink resource usage. However, to allow this scheduling to be fast enough to follow dynamic changes, HSDPA requires that the scheduling be performed at the base station rather than at the RNC. Placing the scheduling function at the base station eliminates some components of communication at the base station-to-RNC interface (Iub interface), thereby reducing the significant delay associated with retransmissions in particular. To do.

Similarly for the extended uplink system, the uplink scheduling function is moved from the RNC to the base station. In such a system, the reception confirmation signal is transmitted on the downlink in order to notify the transmitter (UE) of the reception status of the transmission data packet. Advantageously, in one embodiment of the invention, this signaling method facilitates the use of virtually zero downlink code resources for "ready but inactive" users. Thus, this method facilitates the retention of a large number of ready users, increases system efficiency, and provides additional users with an "always on" Internet experience.

This method takes advantage of the fact that users share channelization code over TDD uplinks (which is not the case with 3GPP FDD). The uplink data is transmitted in blocks during a predetermined period known to both the user and the base station. These periods are called Transmission Time Intervals (TTIs) and may have multiple time slots. In TDD, TTI is 10msec, which matches the radio frame timing of 10msec. One data block is sent for each TTI, and one receipt confirmation indicator is returned for each data block.

The base station scheduler is responsible for distributing uplink time slots and channelization code resources among competing users for each TTI, as will be further described with reference to FIG. Each user scheduled to be active at a given TTI is allowed some of the available uplink time slots and code resources. In one embodiment of the invention, the minimum resource unit (RU) is a single spreading-factor (SF) 16 code for a single time slot. Multiples of these minimum transmission units may be combined to form a large allocation of resources in any one TTI.

In one embodiment of the invention, multiple RUs are in the form of multiple time slots or multiple codes, even though the current 3GPP specification only allows up to two simultaneous codes in a given time slot. It may be assigned to a user. Alternatively, one or more channelization codes with smaller or greater (eg, multiples of SF16) diffusion rates may be assigned in one time slot (eg SF8, SF4, SF2 and SF1). Due to the configuration of the OVSF channelization code used in 3GPP, multiple codes with higher spread rates may be subtend into a common code with lower spread rates. This situation is shown in Figure 7 below. FIG. 7 shows an example of a CDM E-HICH burst structure according to an embodiment of the present invention. C_QⁱIndicates a channelization code having a diffusion rate Q and an index i = 1 ... Q.

The assignment of the first code with the first spread makes it impossible to assign any code with a spread greater than the first spread inherent in the first code to other UEs. Therefore, the code assigned to a user within the allocatable shared uplink transmit resource space is exclusively specified for use by a single user at a given TTI.

For the total uplink resource space, this is defined in two dimensions (time slot and code). At a given TTI, there is a certain number of component time slots and a certain amount of code resources available to share between competing users. Therefore, there is a certain number of resource units (RUs) available for each TTI.

In the following, an embodiment will be described and efficient transmission of acknowledgment / negative response (ACK / NACK) signals is proposed. Thus, some embodiments result in improved scheduling performance, improved quality of service perceived by the end user, and / or improved performance of the cellular communication system as a whole.

FIG. 2 shows in detail UE101, RNC107, and base station 105 of the exemplary cellular communication system of FIG. Base station 105 has an uplink scheduler 221 that schedules uplink transmit resources to active users of the cellular communication system. The uplink transmit resource is authorized by transmitting a resource authorization message from the uplink scheduler 211 to the UE 101 via the base station transceiver 220. The UE 101 receives the resource authorization message through its transceiver 210, and the authorization information is passed to the UE transmit controller 211. The transmission controller 211 serves to select data from the packet data transmission buffer 212 or the packet data retransmission buffer 213. The transmitted user data is supplied from the user data source 214 to the packet data transmission buffer 212 as needed. The transmit controller 211 can also move data from the packet data transmit buffer 212 to the packet data retransmission buffer 213 when a negative response instruction is received from the base station 105 for that data packet.

Therefore, upon receiving the transmit resource permission message, the transmit controller 211 selects data from the transmit buffer 212 or the retransmission buffer 213 as needed. Often, it may be preferable to prioritize retransmission before transmission. The transmission controller 211 transmits the data packet to the base station 105 via the transceiver 210 with the allocated uplink resource.

The code resource used for transmission is configured by the transmit code controller 215. The transmit code controller 215 is notified of the uplink code resources allowed by transmit controller 211. The transmit controller 211 also communicates the transmit resource authorization message to the receive code controller 216. The receive code controller 216 uses this information to guide the receive code to be received by some'receipt confirmation' indicator for the outgoing packet.

In one embodiment, the allocation of at least one downlink code sequence associated with the derived uplink code resource identifier is on the order of substantially a single radio frame or TTI (10 ms) in a short period of time (eg, substantially a single radio frame or TTI (10 ms)). (In) dynamically assigned and reassigned.

Base station 105 receives the transmit data packet with the previously authorized resource and the data is passed to the receive packet data buffer 222. Information about the error state of the received packet is also transmitted to the uplink scheduler 221. Accurately received uplink data packets are forwarded to RNC107 (via the base station to RNC interface 223 and via the Iub interface). These are received by RNC107 via Node-B interface 320. The uplink scheduler 211 may further authorize resources in an attempt to recover erroneous data via retransmission processing.

In either case, the receipt confirmation indicator is generated according to whether the data packet was received incorrectly. If the reception is considered successful, an acknowledgment (ACK) is transmitted via transceiver 220. Otherwise, a negative response (NACK) is sent.

When deciding to allow the uplink resource, the uplink scheduler 221 also notifies the transmit code controller 224 of the allocated uplink code resource. The transmit code controller 224 uses this information to guide the downlink code resource to send the corresponding receipt confirmation indicator. When the receipt confirmation indicator is transmitted, the downlink code resource to be used is configured by the transmit code controller 224 and is therefore associated with the uplink resource assigned to the transmission with respect to the receipt confirmation indicator.

The UE101 transceiver 210 is preconfigured by a receive code controller 216 to detect a receive confirmation indicator transmitted by base station 105. This pre-configuration of the receive code resource is the UE between the receive before the original uplink resource authorization and the uplink code resource used for transmission and the downlink code resource used to receive the receipt confirmation indicator. It can be possible through known mappings in. Therefore, advantageously, long-term allocation of downlink code resources is not required, and downlink code resources are used only when uplink code resources are used (ie, when active uplink transmissions occur). .. In addition, additional signaling overhead for allocating downlink code resources that can reduce system capacity is avoided.

In an embodiment of the present invention, a base station 105 for transmitting signaling information in a time-division bidirectional TD-CDMA cellular communication system is provided. The base station 105 has means for receiving uplink transmissions from the wireless subscriber communication unit 101 (user device (UE), etc.). In particular, the base station 105 has means for deriving the uplink code resource identifier from the uplink transmission. Base station 105 has at least one downlink code sequence and a means of assigning at least one downlink code sequence used to transmit downlink signaling information associated with the derived uplink code resource identifier. It also has a means of transmitting the link transmission to the UE 101.

In one embodiment, base station 105 associates a receipt confirmation indicator code sequence with a code resource used in the corresponding uplink transmission. With respect to ACK / NACK transmission, this embodiment aims to solve the aforementioned drawbacks associated with per-user code reservation in existing 3GPP FDD extended uplink systems for 3GPP TDD systems.

FIG. 3 shows an example of using a channelization code 315 and a scramble code 325 to generate a data stream 340 according to an embodiment of the present invention.

For each user 305, 345, the uplink data is transmitted by the wireless subscriber communication unit in one or more channelization code sequences 310 to generate a signal spread by the channelization code. The signal spread by the channelization code is multiplied by the scramble code sequence 320 in the chip scramble function 325 to generate a transmission signal. The transmission signal is transmitted to the base station receiver 335 on the radio channel 330. The base station receiver 335 demultiplexes the receiving user data stream 340.

FIG. 4 shows an example of resource unit numbering according to an embodiment of the present invention. FIG. 4 shows an example of a situation in which, for example, 10 time slots 410 are available for each radio frame of extended uplink TTI transmission. All resource space 405 (of '16' size) is available in each time slot 410. Therefore, there are a total of '160' RU430s (numbered '0' to '159').

The base station scheduler implicitly knows what radio subscriber communication unit (UE) is assigned what time slot and code resource per TTI. In 3GPP TDD, these resource allocations are transmitted to the UE via a downlink signaling channel (called E-AGCH (Enhanced Uplink Absolute Grant Channel) in 3GPP). Given that the resource allocation given to each user does not overlap with that assigned to other users, it is advantageous to have a unique resource index or "tag" to each actively sending user at a given TTI. May be associated.

The tag may correspond to any resource unit index assigned to the user (such as RU index '47' 425) (because that resource unit different dex cannot be assigned to other users of the same TTI). For simplicity, it is assumed here that the tags are set equal to the lowest numbered RU assigned to the UE for the TTI of interest.

Therefore, if the UE is assigned the following code resources for a particular TTI in a 16 time slot configuration: 1xSF4 Channelization code 2 -Specified extended uplink time slots 1, 2, 3 The tag assigned to that transmission will be the '20'435 number (ie the lowest numbered RU). Therefore, this is the left corner corner of the allocated resource in Figure 4 (the allocated resource is shown as a shaded box). In this example, it should be noted that a single allocation of 4 code spreads in each of the three time slots occupies four minimum resource units (RUs) per time slot. The reason for this is that, in this example, the RU is defined as a single Diffuse 16 code, four of which are inherent in the Diffuse 4 code in the OVSF code tree.

In one embodiment of the invention, the resource tag associated with the user's uplink transmission at a given TTI is a code sequence index corresponding to the code used to convey the next receipt confirmation information for the previous uplink transmission. Used by both the base station and the wireless subscriber communication unit to guide. Therefore, the base station knows what code to send the receipt confirmation indicator, and the wireless subscriber communication unit knows when and where to expect this transmission and how to decode it. There is.

This method avoids the need for long-term reservations for code for a particular user. Advantageously, only the actively transmitting user occupies the code resource of the receipt confirmation indicator.

It is conceivable that this method can be applied to any communication system in which uplink code resources are individually allocated. For example, the above embodiment may be used when the channelization code on the FDD extended uplink is changed to a per-user format.

In one embodiment, TDD E-HICH is a physical channel that is transmitted once per TTI in a single time slot and is configured to carry ACK / NACK information. Advantageously, the ACK / NACK information is synchronized with the extended uplink TTI transmission from the set of users.

This situation is shown in Figure 5. FIG. 5 shows the relationship between E-HICH timing and extended uplink transmission according to an embodiment of the present invention. The timing relevance is shown as code 505 for time slot 510. For a particular frame'F', there are multiple downlink transmissions 515 and multiple uplink transmissions 520.

In one embodiment of the invention, the (single) E-HICH physical channel uses the SF16 spread code in a single downlink time slot per transmit time interval (TTI). The E-HICH physical channel carries one receipt confirmation indicator for every 525 E-HICH user sets. Indicators are code time division multiplexing (CDM) within a single SF16 code.

A set of users whose ACK / NACK information is transmitted on a particular E-HICH is called an "E-HICH user set". These are active users. That is, in the extended uplink transmission 520 of TTI (or frame) F, ACK / NACK is TTI (or frame) F + T._A530, which is returned in the downlink time slot 540 of E-HICH535. Therefore, the frame "F + T"_AHas an E-HICH downlink transmission 540 with an ACK / NACK indicator for the uplink transmission of frame F , and may further have an uplink transmission 545.

The examples described relate to the CDM of the reception confirmation indicator on the E-HICH channel, but it is conceivable that an alternative example in which the reception confirmation indicator is time division multiplexing (TDM) to the E-HICH channel can be used. Be done. There is a particular advantage of the CDM method over TDM due to the unique feature of the CDM embodiment that allows per-user power control while keeping the average slot power constant and equal to the mid-amble power. obtain.

Therefore, according to an embodiment of the present invention, a wireless communication protocol is provided that supports downlink transmission from a base station to a wireless subscriber communication unit, whereby downlink transmission is either previous uplink transmission or previous. Has at least one downlink code sequence associated with the derived uplink code resource identifier for the authorization message of.

Downlink code C₁₆⁹With respect to the assignment of 630 to E-HICH, one embodiment of the invention may be viewed as an extension of the OVSF code shown in FIG. 6 to tree 600. R in total inherent in E-HICH code 610_maxThere are orthogonal series 630 available for. R_maxIs greater than or equal to the sum of the shared uplink transmission resource units that can be allocated by the system for each TTI in the extended uplink transmission within the cell.

In one embodiment, the CDM E-HICH burst configuration 700 may be configured as shown in FIG. In a normal TDD burst, there are two payload parts 715, 730 for each user 705 separated by a mid-amble part 720. The spare bit 725 distinguishes the payload parts 715, 730 from the mid-amble part 720. A guard period (GP) 735 is inserted at the end of the burst.

In this example, a total of '240' orthogonal sequences are shown for TDD so that the RU numbering extends to both the up and down links of the frame (16 of 15 time slots each for each radio frame / TTI). Resource unit). Therefore, this configuration is not affected by a specific frame configuration or the uplink (UL) / downlink (DL) division point or the like. The '240' selection also fits well for the payload capacity of SF16's E-HICH physical channels ('244' bits for burst type '1' and '276' bits for burst type '2' for 3GPP. It reduces wasted payload resources and allows the same configuration to be used for both burst types.

The '240' selection also allows flexible selection of orthogonal code sets. In one embodiment of the invention, to avoid the need to store the complete set of '240' x '240' codes (equivalent to 57.6 kbits), a code of length 240 is "on". -the-fly) It is desirable that it can be generated. In one embodiment, the code of length 240 may be generated by a simple calculation means.

Advantageously, in alternative embodiments, it is possible that a code of length 240 could be generated from a small code set. Here, for example, by selecting '240', it becomes possible to use the continuous two-stage diffusion process 800 as shown in FIG. This can reduce UE complexity and memory requirements.

For example, the example shown in FIG. 8 uses a continuous two-step spreading operation that uses continuous coding in two short orthogonal sequence sets to generate a code of length '240'. Therefore, FIG. 8 shows a first diffusion step at a diffusivity length of '20' bits and a second diffusion step at a diffusivity length of '12' bits, according to an embodiment of the present invention. It shows that. Here, a single bit 805 of an acknowledgment or a negative response is input to the first iteration block 810, and the single bit 805 is repeated 20 times. This iterative series is input to the first multiplication function 820 and multiplied by the primary code 815 of length '20'.

The multiplied iterative sequence is input to the second iterative block 825, and the iterative sequence is repeated 12 times. This iterative series is entered into the second multiplication function 835 and multiplied by the '12' length primary code 830. The next output 840 is the desired set of 240 bitcodes.

Therefore, this example provides an efficient, low-complexity implementation. The UE only needs to store one '12' x '12' code set and a '20' x '20' code set. Advantageously, this is significantly smaller than '240' x '240'. Therefore, in this embodiment, a common signature sequence length '240' is used regardless of the burst type, which simplifies the implementation of the UE. Since the payload sizes of burst type '1' and burst type '2' are 244 bits and 276 bits, respectively, there are 4 spare bits for burst type '1' and 36 spare bits for burst type '2' as a result. There is a bit. The loss of processing gain from these unused "spare" bits is relatively small (ie, determined to be 0.07 dB and 0.6 dB, respectively).

Those skilled in the art will recognize that more stages than two-stage processing can be used. It is possible that alternative code sets may be used, depending on the intended use, the reduced complexity of the UE, and the memory requirements used.

A TDD E-HICH Code Division Multiplied (CDM) transmitter configuration 900 according to an embodiment of the present invention is shown in FIG. According to one embodiment shown in FIG. 9, the primary code 815 may consist of rows of a Hadamard matrix of rank '20'. Secondary code 830 may also consist of rows of a Hadamard matrix of rank '12'.

The code indexes 815 and 830 used with the Hadamard matrix (i = 0 ... 19 for the primary code set and j = 0 ... 11 for the secondary code set) are derived as follows.

<maths num="1"><img file="JP4875705B2_D0001.tif" /></maths>However, "r" is the above-mentioned resource index tag. Further, in one embodiment shown in FIG. 9, the row inversion variant and scramble code may be applied to Hadamard code sets 815, 830, for example using the bit scramble procedure 930 of 3GPP Release 99. Such line inversion variants and scrambled code may be applied 925 after adding some unused (spare) bits. Line reversal variants and scrambled codes may be used to improve peak-to-average power characteristics and provide protection against the Doppler effect.

Following the application of the R99 bit scramble code, the signal may be QPSK (quadrature phase shift key) modulated 935. The QPSK modulated signal is multiplied by the user-specific gain 940 with the multiplication function 945. The resulting signal is multiplexed with another user's signal with the multiplexing function 950. Next, the E-HICH channelization code 955 is applied to the multiplex signal in one embodiment with a spreading function 960 that applies the spreading code of SF16. The output signal is the CDMA transmission signal 965 of the '1952' or '2208' chip. One or more midamble sequences may then be inserted into the CDMA transmit signal 965.

In one embodiment of the invention, a method 1000 for transmitting and receiving signaling information in a cellular communication system is described as shown in FIG. This method has a communication step between the wireless subscriber communication unit 1050 (user equipment etc.) and the base station 1010 (Node B etc.).

This method involves allowing Node B1010 to allow one or more uplink transmit resources to UE1050 in step 1015. At step 1055, UE1050 receives permission for one or more uplink transmit resources. The UE 1050 then sends an uplink message using all or part of the allocated uplink resources, as shown in step 1060. In step 1020, Node B1010 receives the uplink transmission.

In particular, both UE1050 and Node B1010 derive downlink code resource identifiers based on authorization messages or uplink resources used, as shown in steps 1065 and 1025. Node B1010 is the at least one downlink code used to convey the downlink signaling information associated with the derived uplink code resource identifier (and thus the uplink resource used for uplink transmission). Assign a series. Further, as shown in step 1030, Node B1010 uses downlink resources derived from authorized or used uplink resources to send downlink signaling with at least one downlink code sequence to UE1050. .. At step 1070, UE1050 receives downlink signaling on the derived downlink resource. UE1050 is able to decode downlink transmissions because it independently derives the same downlink resources as Node B1010 based on the allowed or used uplink resources.

With respect to the above description and according to the embodiments of the present invention, the term "code sequence" refers to time sequences (as is common in CDMA systems) and frequencies in other cellular communication systems (such as OFDM or FDMA). It is considered to include a series of sinusoidal functions equal to subcarriers and a common time / frequency code in systems that use some combination of TDMA, FDMA, and CDMA. As such, the embodiments of the present invention are also applicable to other communication systems, whereby the user allocates resources in the form of time / frequency code or subcarrier of time, frequency, or primary carrier frequency. Be done.

For clarity, it can be seen that the above description describes embodiments of the invention with respect to different functional units and processors. However, it is clear that some appropriate functional distribution between different functional units or processors may be used without departing from the present invention. For example, a function indicated to be performed by different processors or controllers may be performed by the same processor or controller. Therefore, a reference to a particular functional unit is considered only as a reference to the appropriate means of providing the desired function, rather than indicating a strict logical or physical structure or configuration.

The present invention may be implemented in any suitable form, including hardware, software, firmware or any combination thereof. Optionally, the invention may be at least partially implemented as computer software running on one or more data processors and / or digital signal processors. The elements and components of the embodiments of the present invention may be physically, functionally and logically implemented in any suitable manner. In fact, the function may be implemented in a single unit, in multiple units, or as part of another functional unit. Thus, the invention may be implemented in a single unit or physically and functionally distributed between different units and processors.

Although the present invention has been described with respect to some examples, it is not intended to be limited to the particular form shown herein. Rather, the scope of the invention is limited only by the claims. Moreover, although the functionality appears to be described for a particular embodiment, one of ordinary skill in the art will recognize that various features of the described embodiment may be combined in accordance with the present invention. In the claims, the term having does not exclude the existence of other elements or steps.

Further, although described individually, multiple means, elements or steps of method may be implemented, for example, by a single unit or processor. Further, individual features may be included in different claims, which may be advantageously combined in some cases, and inclusion in different claims is not feasible and / or advantageous for the combination of features. It does not mean that there is none. Also, the inclusion of a feature in one claim category does not mean a limitation to this category, but the feature can be applied to other claims categories as needed. Indicates that. Moreover, the order of the features in the claims does not indicate the particular order in which the features must be operated, and in particular the order of the individual steps in the method claims must be performed in this order. It does not indicate that it should not be. Rather, the steps may be performed in any suitable order. Moreover, references to the singular do not exclude multiple. Therefore, references to "one", "first", "second", etc. do not exclude more than one.

<figref num="1">An example of a cellular communication system in which certain embodiments of the present invention can be used.</figref><figref num="2">UEs, RNCs and base stations according to certain embodiments of the present invention</figref><figref num="3">An example of using a channelization code and a scrambled code to generate a data stream according to an embodiment of the present invention.</figref><figref num="4">Example of resource unit numbering according to an embodiment of the present invention</figref><figref num="5">An example of the relationship between E-HICH timing and extended uplink transmission according to an embodiment of the present invention.</figref><figref num="6">Example of extension to OVSF (Orthogonal Variable Spreading Factor) according to an embodiment of the present invention</figref><figref num="7">An example of a CDM (Code Division Multiplexed) E-HICH burst configuration according to an embodiment of the present invention.</figref><figref num="8">Continuous two-step diffusion operation according to an embodiment of the present invention</figref><figref num="9">Configuration of CDM Transmitter for TDD E-HICH According to Some Examples of the Invention</figref><figref num="10">A method of transmitting and receiving signaling information according to an embodiment of the present invention.</figref>