Packet control channel feedback support for contention and reservation based access

Feedback support for packet control channel based on competition and reservation access

[Background of the invention]

The applicants invention is about the long-distance communication of electric power, and more specifically about the various operation modes (analog, digital, dual-mode, etc.) of wireless communication systems such as cellular and satellite radio systems and methods such as frequency division multiple access. (FDMA), Time Division Multiple Access (TDMA), Code Division Multiple Access (CDMA), and hybrid FDMA/TDMA/CDMA access technology. More specifically, the present invention relates to the time slot format of the packet data channel transmission between the communication system and the mobile station.

Figure 1(a) shows the forward (or downlink) digital control of a series of time slots 1, 2,..., N that are configured to be included in the continuous time slots 1, 2, ... transmitted on the carrier frequency General example of channel (DCCH). These DCCH slots may be defined in radio channels such as those specified by TIA/EIA/IS-136, and may consist of the nth time slot in a series of consecutive time slots as shown in Figure 1.

As shown in Figure 1(a), the DCCH time slots are organized into super frame (SF) and each super frame contains several logical channels carrying different types of information. "Each logical channel in the super frame can be Configure one or more DCCH time slots. The example of the downlink super signal frame in Figure 1(a) contains three logical channels: one contains six consecutive time slots for additional information on the broadcast control channel (BCCH); one contains one The time slot is used for the paging channel (PCH) for paging messages; and an access response channel that contains a time slot for channel designation and other messages. The remaining time slots in the sample super signal frame in Figure 1(a) can be dedicated It is used by other logical channels, such as the additional paging channel (PCH).

Figure 1(b) shows an example of the information format of a forward DCCH time slot. The number of bits in each field here is marked below the field. The bits transmitted in the SYNC message are traditionally used to ensure accurate reception of the CSFP and DATA fields. SYNC information carries a predetermined bit pattern for mobile stations to find the beginning of the time slot. "SCF information is used to control the random access channel (RACH) used by the mobile station to request access to the system. The frame phase value is for the mobile station to find the beginning of each super frame.

The current systems specified by the TIA/EIA/IS-54 and TIA/EIA/IS-136 standards use circuit switching technology, which is a way to establish an actual call connection and maintain the connection in the process of exchanging data in the communication endpoint system "Link-oriented" communication. Circuit-switched direct connections are seen as open pipelines, allowing end-point systems to use the circuit as they see fit. Although circuit-switched data communication may be quite suitable for fixed-bandwidth applications, it is quite inefficient for low-bandwidth and "bursty" applications.

Compared with circuit switching technology, packet switching technology that can be connection-oriented (such as x.25) or "non-connection-oriented" (such as network protocol "IF) does not require the establishment and release of actual connections. This approach reduces Data delay and increase the channels efficiency when dealing with relatively short, cluster-type, or interactive services. A non-connection-oriented packet switching network distributes routing functions to multiple routing locations, thereby avoiding concentrated use The traffic frequency that may occur when the central switching hub is used. The data is "encapsulated" by the appropriate end-point system addressing, and then transmitted in independent units on the data path. The intermediate system between the communication endpoint systems, sometimes called a "router", determines the most appropriate path on the basis of each packet. Routing decisions are based on several characteristics, including: the lowest cost path or cost metric; link capacity; the number of packets waiting to be transmitted; the security requirements of the link; and the operational status of the intermediate system (node).

Encapsulated networks, such as the Internet or corporate LANs, are an integral part of today's corporate and communications environment. When mobile computing in these environments is becoming more and more popular, wireless service providers using TIA/EIA/IS-136, etc. are in the best position to provide access to these networks. However, the data service provided or suggested by the cellular system is usually based on a circuit-switched mode of operation, providing a dedicated wireless channel for each effective mobile user.

However, the first edition of the Cellular Digital Encapsulation Data (CDPD) system specification (1993, July), which is quoted here as a reference, describes the current advanced mobile phone service (AMPS) system, which is the North American analog cell The concept of using available radio channels in the system to provide encapsulated data services. The specification includes functional topics such as external interfaces, air link interfaces, services, network architecture, network management, and operations.

The infrastructure on which the designated CDPD system is based is quite independent of the existing AMPS infrastructure. The commonality with the AMPS system is basically limited to the use of the same type of radio frequency channel and the same base station location (the base station used by CDPD can be new and exclusive to CDPD), and one of the two systems is used Signal interface to coordinate channel assignment.

Despite the emergence of CDPD, there are still digital cellular (such as DAMPS, IS-136) systems that provide general packaged data services based on the shared packaged data channel provided by optimizing packaged data. need. This application is aimed at link-oriented networks and non-link-oriented encapsulated data networks specified by the TIA/EIA/IS-136 standard to provide systems and methods that combine the advantages of the two. Specifically, the present invention is directed to technologies for accessing wireless packet data networks, such as using low-complexity and high-output existing non-connection-oriented network protocols.

[Summary of Invention]

According to a specific embodiment of the present invention, the communication system provides packet control channel feedback information to the mobile station in communication with the system. In addition to other tasks, the system needs to respond to the burst group of packet data information transmitted by the mobile station. .

The purpose of an embodiment of the present invention is to provide a method for interrupting transmission to allow other mobile stations that are trying to access the system or have accessed the system but are transmitting packet data information to provide the packet. Maximum efficiency of sealing data channels. According to the present invention, the envelope control channel feedback information includes several flags: received/not received (R/N), partial echo (PE), and partial echo identifier (PEQ). PEQ allows the communication system to interrupt the transmission from a mobile station to allow the transmission of another mobile station. By setting the PEQ to a different value, the communication system can dynamically configure the ownership of the RACH sub-channel, and thereby instruct mobile stations whether their ownership is temporarily interrupted and re-assigned to other mobile stations.

Especially according to specific embodiments, the value of PEQ has been optimized as follows: (1) Release the BRI field of the existing IS-136 physical layer for use by other functions, (2) Allow contention-based access architecture (such as time slot Type ALOHA or CSMA) at the same time with multiplexing characteristics (reservation-based access) operating in the uplink of the same channel, (3) providing all data users of the same channel with the same delay application regardless of load, (4) sub-channel interception Fast detection and response.

[Detailed description of preferred embodiments]

The present invention relates to a time slot format between a communication system and a mobile station in the transmission of an encapsulated data channel. To help understand the present invention, the structure of the logical channel set of D-AMPS is described in FIG. 2, which includes the structure according to the present invention. As shown in the figure, the digital control channel (DCCH) has a reverse access channel (RACH) and a broadcast control channel (BCCH) in the reverse direction (uplink), and a SPACH channel (broadcast channel, short message service, Access response channel), a shared channel feedback (SCF) and a reserved channel (RSYD) in the forward direction (downlink). The packet control channel (PCCH) has a packet random access channel (PRACH) and a packet broadcast control channel (PBCCH) in the reverse direction, a PSPACH channel (the packet calling channel PPCH and a packet access response Channel PARCH), the package control channel negative (PCCF) and a reserved channel in the forward direction.

Figure 3 shows an example of how a third-level message corresponds to a dedicated PCCH of several second-level frames, an example of a second-level frame corresponding to a time slot, and an example of a time slot corresponding to a PCCH channel. The length of the FPCCH time slot and PRACH cluster is fixed. There are three possible forms of PRACH bundles with different lengths (normal, abbreviated, and auxiliary). In Figure 3, it is assumed that the FPCCH time slot in the full-speed PCCH is located on the physical layer.

Please note that the time slot 30 in FIG. 3 is slightly different from that in FIG. 1(a). In this specific implementation, the time slot format is divided into seven fields; one synchronization field (SYNC) to provide mobile station synchronization information, one package control channel counter field (PCCF), and one first data (DATA ) Field, a coded super frame phase/encapsulation control channel response (CSFP/PCCF) field, a second data field, a second package control channel response (PCCF) field, and a reservation (RSVD) field. Therefore, it can be seen that the SCF field of IS-136 has been replaced by the PCCF field in the encapsulated data communication, and the bit size in the field structure remains unchanged.

The PCCF field is used to control the access of PRACH and contains several flags: received/not received (R/N), partial echo (PE), and partial echo identifier (PEQ). However, please note that according to the present invention, the package control channel feedback field does not include the busy/reserved/idle (BRI) flag of the aforementioned parent invention. The R/N flag is used to indicate the received/unreceived status of individual bits sent to the base station in the PRACH. Part of the echo flag is used to indicate that the communication system correctly received the initial packet of which mobile station attempted to make a contention-based access. For this purpose, the communication system can set the PE to be equal to the seven least important bits in the mobile station identification part of the sent mobile station access attempt. When the mobile station is in the process of receiving automatic retransmission request mode, some echo flags are also used to induce or inquire the mobile station's response. For this purpose, the communication system can set the PE to be equal to the PE (PEA) assigned to the mobile station in the first time slot sent to the mobile station under the specified automatic repeat request (ARQ) mode system. . The partial echo flag is also used to indicate when a mobile station attempting to make a non-ARQ-related appointment-based access should start its message transmission. For this purpose, the communication system can set the PE equal to the seven least important bits of the mobile station identification that the communication system hopes to provide access opportunities based on reservations.

In addition to the other functions described below, the communication system uses the PEQ flag to dynamically specify the sub-channels of PRACH to provide an effective mechanism to interrupt the packet data transmission of the first mobile station, and thereby allow other systems that are trying to access the system. Or the packet data transmission of the mobile station that has been connected to the system and is in the process of transmitting packet data information. For example, assuming that a full-speed TDMA channel is logically divided into three sub-channels, there are a total of nine sub-channels available for multiplexing among data-encapsulated users in a triple-speed IS-136 form of enveloped data system.

According to a specific embodiment of the present invention, the CSFP/PCCF field of the time slot format 30 in FIG. 3 is used to transmit information about the phase of the super frame (so that the mobile station can find the start of the super frame) and provide the part Information about the echo identifier. In this specific implementation, the CSFP/PCCF field contains 12 bits (DO-D11).

The PEQ flag can be specified in two bits in the 12-bit CSFP/PCF field. For example, the PEQ flag can be assigned to D6 and D5, but the present invention is not limited to this. Table 1 shows an example of the coding rules for the PEQ flag. When bits D6 and D5 are set to zero, it means that there is no interruption and each mobile station maintains its current sub-channel ownership. When bits D6 and D5 are set to zero and one, respectively, the ownership of the sub-channel is assigned to the mobile station indicated in the coded partial echo (PE) field. When bits D6 and D5 are set to one and zero, respectively, the ownership of the sub-channel is suspended to serve contention-based access attempts. Please note that the owner of a sub-channel must have sent two or more bundles of news to consider these PEQ flag settings as an instruction to suspend ownership. Finally, when bits D6 and D5 are set to one at the same time, the ownership of the sub-channel must be confirmed. Each mobile station that owns the sub-channel checks the CPE field to make sure it is the owner of the sub-channel. Professionals skilled in the art must know that other bit pairs can also be used, and the present invention is not limited to the above-mentioned bit pairs (D6 and D5).

<img file="TW425791B_D0001.tif" />

The PCCF flag is transmitted in the FPCCH time slot, and among other functions, it also indicates the reception status of the communication system to the previously transmitted cluster of RPCCH (ie, PRACH). A mobile station with reservation-based access or competition-based access is waiting to read the PCCF flag to determine when to start its access attempt. The appointment-based and competition-based access are described in detail in the aforementioned parent application, and will not be repeated here.

According to a specific embodiment of the present invention, the aforementioned PCCF field supports both competition-based and reservation-based access in the following ways: (1) Efficiently handle a single cluster of communication access attempts, (2) Optimize the PCCF field Bit space, (3) reliably handle sub-channel transfers, and (4) support dynamic allocation of access opportunities based on competition.

For example, in the parent application case, PEQ=INT_1 (used to respond to the first packet of the access attempt) indicates that the mobile station with the PEQ value found in the corresponding PCCF field has lost its sub-channel ownership until Until further notice. In this example, the ownership of the sub-channel will be returned to the mobile station that owned the sub-channel before PEQ=INT_1. This function may be appropriate under certain circumstances, but the applicant separately provides the above NO_INT, PE_INT and SO_INT values of PEQ to provide greater value when re-assigning sub-channel ownership after receiving the first cluster of access attempts.offlexibility.

In the parent application case, the BRI field is used to indicate whether the PRACH is busy, reserved, or idle. Since BRI=idle is logically equal to PEQ=SO_1NT, and PEQ=NO_INT and PE_INT are included in BRI=busy, reserved, the applicant believes that the BRI field can be abandoned to provide additional bits for the PCCF field The space is used for other functions.

When, for example, the current owner of the sub-channel does not correctly detect the intentional ownership transfer (for example, when the current owner of the sub-channel misses PE1_INT due to a PEQ reception error), the transfer of the ownership of the sub-channel may be potentially dangerous. Using the above example of PEQ coding rules can enhance the ease of sub-channel transfer. For example, the WA_INT value of the above PEQ allows mobile stations to detect missed sub-channel ownership transfers.

For example, the base station may use the PE_INT value of PEQ to reassign sub-channel ownership from one mobile station to another. Immediately, if the original owner makes a mistake or fails to give up the ownership of the sub-channel, the base station can send PEQ=WA_INT in the next PCCF of the sub-channel, providing the mobile station to check the CPE field and give up the sub-channel for the second time. Opportunities for channel ownership. Therefore, if an mobile station unexpectedly receives the PEQ value of WA_INT in all sub-channels that it believes to be it (that is, the value does not immediately follow PE_INT), the mobile station will know that it missed one Transfer of ownership of sub-channels. Then, the mobile station will relinquish the ownership of the sub-channel and think that the last burst it transmitted needs to be retransmitted.

In addition to improperly retaining the ownership of the sub-channel, the PEQ coding rules in the above example are also useful when dealing with the opposite situation, that is, when another mobile station incorrectly assumes that the ownership of the sub-channel is obtained from the legal owner. This situation called "sub-channel blocking" is described in more detail below. The initial access to the radio communication system may be based on technologies well known in the packet data industry, such as Time Slot ALOHA and/or Carrier Sense Multiple Access (CSMA), using a competition-based access methodology. It should be noted that the mobile station looking for PEQ=SO_INT is basically a system access in the form of CSMA, so the mobile station will first receive information (such as PEQ) from the communication system before attempting an access. CSMAs scope of operation supports both competition-based and appointment-based access. "As far as time slot ALOHA access is concerned, the mobile station will not wait to receive any information from the communication system before deciding when to make an access attempt. Slotted ALOHA only supports competition-based access within the scope of operation. A PCCH may support CSMA and slotted ALOHA at the same time, thus giving the servo system more flexibility. Mobile stations looking for access opportunities may use them for the first touch Any type of arrival time slot one is CSMA or time slot ALOHA.

For example, system broadcast information (such as on PBCCH) can be used to notify mobile stations of time slot-based ALOHA access opportunities (that is, they exist), and these opportunities can be positioned through BCCH information. Then the system can set PEQ=PE_INT and CPE=a PE value that is currently invalid to ensure that the effective mobile station does not use the time slotted ALOHA access opportunity. The selection of the invalid PE can use the PE value that is the farthest from the valid PE from the coding point of view. This approach minimizes the possibility of another effective mobile station misreading the CPE and taking over the ownership of a sub-channel of a time slot that is marked as a time slot ALOHA access opportunity. By setting PEQ=SO_1NT, the mobile station can be informed of the access opportunity based on CSMA, which can be provided by the system on a real-time basis.

Indeed, professionals skilled in the art know that the PEQ described in the above-mentioned parent application can also be used to provide CSMA and slot ALOHA access as described below. CSMA access opportunities can be communicated to the mobile station by setting BRI=idle and PEQ=RSVD or PEQ=INT_2 and CPE=an invalid PE. Time slot ALOHA access opportunities can use the earlier PEQ encoding structure to use broadcast information and set BRI=reservation, PEQ=INT_2 and CPE=an invalid PE support.

In any of the above situations, mobile stations that have successfully established initial access (that is, have sent the first packet of their packet data transaction) will ignore those marked as CSMA or time slot ALOHA access opportunities Uplink time slot. Once the mobile station successfully establishes the initial access and the PCCH decides to manage packet data transactions locally (that is, in the PCCH itself instead of delivering the transaction to a packet traffic channel), the PCCF architecture supports the PCCH uplink bandwidth at multiple Multiplexing between users of a system.

After describing the exemplary PEQ encoding architecture according to the present invention, the following description will provide additional details about the mobile station's response to the response information sent by the PCCF. Initially, the difference between the time slotted ALOHA access attempt of the mobile station and the CSMA access attempt according to the present invention is that the time slotted ALOHA access attempt does not require the mobile station to monitor the PCCF, but the mobile station that requires CSMA access will Monitor the PEQ field of PCCF to identify access opportunities, as shown in Table 2.

<img file="TW425791B_D0002.tif" />

Once the mobile station uses these two competition-based access architectures to access the radio communication system, the mobile station will monitor the PCCF field as a countermeasure according to the above table. In the response after transmitting the first burst, the mobile station will monitor the fields shown in Table 3.

<img file="TW425791B_D0003.tif" />

Note 2: Check only when PEQ 2 PE 1 NT

Note 3: Check only when PEQ=PE_INT or WA_INT

It can be seen from Table 4 that mobile stations that do not own a specific sub-channel do not care about whether the previous transmission of the sub-channel is received or not, but only transfers the ownership of the sub-channel. For example, when PEQ=PE_INT, it cares about the response in the encoding part. The value of the wave field. On the other hand, the owner of the sub-channel will always be concerned about whether the packet sent by it is received and will also observe the CPE field under the instruction of the base station, that is, when PEQ=WA_INT.

After discussing which fields the mobile station will monitor, we will now discuss how the mobile station handles these fields in the following table, where the label "X" represents "anything". For example, a mobile station that has informal ownership of the sub-channel (that is, the mobile station maintains the ownership of the sub-channel after transmitting the first packet of its access) will respond to the PCCF field as shown in Table 5. feedback of.

<img file="TW425791B_D0004.tif" />

As seen in Table 5, the value of R/N indicates whether the last packet must be resent. When R/N=N, the last packet must be resent. Under normal circumstances, when R/N=R, the last packet does not need to be resent, except when CPE=non-conformance and PEQ=WA_INT, it shows that the mobile station missed the above-mentioned sub-channel transfer (that is, PEQ=PE_INT). Down. The aforementioned Table 1 describes the PEQ values NO_INT, PE_INT, and SO_INT for maintaining and suspending ownership of the sub-channel. When PEQ=WA_INT, the mobile station rechecks the CPE and maintains or relinquishes the ownership of the sub-channel based on the result of the comparison. The system uses the PEQ value to exclude improper sub-channel owners.

Some mobile stations that may or may not own one or more sub-channels will send out at least the first cluster of access attempts and expect to obtain ownership of the sub-channels. These "exploratory" mobile stations will monitor the PCCF to determine whether they can obtain ownership as shown in Table 6.

<img file="TW425791B_D0005.tif" />

It can be seen from the table that the probed mobile station can obtain the ownership of the sub-channel only when the base station re-designates the sub-channel as the CPE value that reflects the identity of the probed mobile station.

Mobile stations seeking initial access (that is, their first packet has not yet been sent) and thus acquired ownership may use CSMA access under the instruction of PEQ=SO_INT to try to access the system. When PE=SO_INT is detected, these mobile stations send their first burst and respond to the PCCF feedback as shown in Table 7.

<img file="TW425791B_D0006.tif" />

According to Table 7, if the cluster is not received, the mobile station will give up the ownership of the sub-channel and retry the access using the retry mechanism described in the parent application. Similarly, if the action station is not the winner of the access based on the competition (ie CPE=non-conformance), the action station must also give up ownership and retry its access. Otherwise, if the cluster is received correctly, CPE=conforms and PEQ is not equal to PE_INT, the first cluster transmitted by the interrupting mobile station is successfully received, but the winning/interrupting mobile station must abandon the sub-channel. Under these circumstances, the victory/interrupted action station immediately becomes a "exploration" action station and follows the rules listed in Table 6. On the other hand, if the cluster is received correctly, CPE=conformity and PEQ=PE_INT, the winning/interrupted action station will claim sub-channel ownership (ie, informal ownership) and follow the rules of Table 5.

When the mobile station is interrupted by receiving the feedback PEQ=SO_INT, it will continue to monitor the PCCF of the sub-channel it previously owned as shown in Table 8.

<img file="TW425791B_D0007.tif" />

Therefore, if the mobile station receives PEQ=PE_INT and CPE=non-conformance or WA_INT, it will give up the ownership of the sub-channel and wait for a new sub-channel according to the rules in Table 6. If PEQ=NO_INT or PEQ=PEQ_INT and CPE= match, the original owner will retrieve the ownership of the sub-channel and continue to transmit the burst burst and process feedback according to Table 5. When the interrupted mobile station recognizes PEQ 2 50INT, the other mobile station is being granted a CSMA access opportunity and the interrupted mobile station will continue to monitor another time slot of the sub-channel according to Table 8.

"Probing" mobile stations, that is, those who have successfully sent the message at least once and are seeking ownership of the sub-channel, will not respond to the feedback corresponding to the sub-channel being used by the interrupted mobile station. Therefore, the response form of these "exploration" mobile stations is shown in Form 9.

<img file="TW425791B_D0008.tif" />

The mobile station can also obtain access to the sub-channel when responding to the PEQ=PE_INT in the PCCF and the CPE match. This kind of mobile station will send a cluster of information and respond to the feedback as shown in Table 10.

<img file="TW425791B_D0009.tif" />

It can be seen that the response rules for mobile stations transmitted on the sub-channels obtained through PEQ=PE_INT are almost the same as those of the mobile stations obtained through PEQ=SO_1NT in Table 7 above, except that when R/N=R and CPE= match. The mobile station's response to PEQ=WA_INT will obtain the ownership of the sub-channel. When the mobile station is interrupted by receiving the feedback PEQ=PE_INT, the mobile station will continue to monitor the PCCF corresponding to the sub-channel it used before, as shown in Table 11.

<img file="TW425791B_D0010.tif" />

Also similar to Table 9, the Exploratory Action Station will not obtain the ownership of the sub-channel that transferred ownership in the previous PCCF feedback information, regardless of the different PCCF values shown in Table 12.

<img file="TW425791B_D0011.tif" />

As mentioned above, the encapsulated data transmission according to the specific embodiment of the present invention also provides robustness in the field of sub-channel interception processing. This phrase means that the ownership of the sub-channel is unintentionally transferred from one mobile station to another. According to the present invention, each MAC layer frame transmitted by the mobile station on the uplink may contain the mobile station identification (MSID) when performing cyclic redundancy check (CRC) calculation. This approach allows the base station to easily detect the interception of the sub-channel, because the received CRC will be incorrect due to the unknown MSID included in the CRC calculation. When this situation is detected, the base station can perform the following actions in the downlink time slot to provide PCCF feedback to the intercepted time slot for recovery:

Set R/N=not received

Set PEQ=PE_INT

Set CPE=Intentional MSID

With the above response, the intercepted mobile station will immediately give up the ownership of the sub-channel and the intentional mobile station will reconfirm its ownership of the sub-channel. Both mobile stations will find that their last MAC layer frame must be resent.

To describe the effectiveness of the present invention in processing sub-channel interception, consider several interception scenarios below:

Mobile station 1 (Msl) has sub-channel 1

Mobile Station 2 (MS2) is waiting to assign a sub-channel

Base station sends PEQ=NO_1NT

The base station also transmits CPE=MSI

<u>Case 1: Triple error received in the field</u>

Consider the occurrence of the following events.

1. MSI incorrectly received PEQ as S0_INT and gave up sub-channel 1

2. MS2 receives that PEQ is PE_INT and CPE is MS2, and therefore claims sub-channel ownership.

3. The base station receives a MAC layer frame from MSZ and detects a potential interception condition due to CRC error.

4. In the downlink feedback (PCCF) of subchannel 1 corresponding to the intercepted slot, the base station sets R/N=not received, PEQ=PE_INT and CPE=MSID of MSI.

5. MSZ abandons subchannel 1 and MSI reconfirms its ownership.

6. MSZ knows that the MAC layer frame transmitted at the end of sub-channel 1 received an error and must be resent.

<u>Situation=: Double error received in the field</u>

1. MSI receives PEQ as NO_INT and maintains the ownership of sub-channel 1.

2. MSZ receives PEQ as PE_INT and CPE as MS2 and claims the ownership of subchannel 1.

3. Without the capture effect, the base station began to receive incomprehensible information and detected potential interception conditions due to CRC errors. Please note that "capture effect" means that two mobile stations transmit at the same time and the received signal of one is stronger than the other so that the base station can still correctly receive the signal from the stronger mobile station.

4. In the downlink response (PCCF) of subchannel 1 corresponding to the intercepted slot, the base station sets R/N=not received, PEQ=PE_INT and CPE=MSID of MSI.

5. MS2 abandons subchannel 1 and MSI reconfirms its ownership.

6. MS1 knows that it received an error in the last MAC layer frame transmitted in subchannel 1 and must resend it.

7. MS2 knows that the last MAC layer frame transmitted in sub-channel 1 received an error and must be resent.

<u>Case 3: Double error in field reception</u>

1. MS1 receives PEQ as NO_INT and maintains the ownership of subchannel 1.

2. MS2 receives PEQ as PE_INT and CPE as MSZ and claims the ownership of subchannel 1.

3. Under the capture effect, the base station receives the MAC layer frame from MS2 and detects a potential interception condition due to the CRC error.

4. In the downlink response (PCCF) of subchannel 1 corresponding to the intercepted slot, the base station sets R/N=not received, PEQ=PE_INT and CPE=MSID of MS1.

5. MS2 abandons subchannel 1 and MS1 reconfirms its ownership.

6. MS1 knows that it received an error in the last MAC layer frame transmitted in subchannel 1 and must resend it.

7. MS2 knows that the last MAC layer frame transmitted in sub-channel 1 received an error and must be resent.

After explaining the operation of the encapsulated data communication system and method according to the present invention in detail, some general access examples will be provided below with reference to FIGS. 4 to g.

In the full-speed PCCH, the PRACH cluster and FPCCH time slots are multiplexed to establish three different access paths, as shown in Figure 4. Assuming that path 1 (P1) in FPCCH indicates that the next P1 cluster in PRACH is available, for example, PE=SO_INT, and has been selected as an access attempt, a mobile station will send its first time at this time Reaching the cluster message (after receiving the entire P1 time slot of FPCCH). The mobile station immediately starts to read the PCCF flag of the next P1FPCCH time slot after it finishes transmitting its access packet to determine whether the communication system has received the mobile station's initial packet.

Figure 5 depicts the relationship between the FPCCHPCCF flag and PRACH (RPCCH) clusters. Here, a mobile station carries out contention-based access and transmits two clusters. The arrows show the sequence or events corresponding to the access attempts. Therefore, follow the arrow from left to right on the PRACH subchannel P1, and the PEQ part of the PCCF flag first indicates whether the next P1 cluster of PRACH is available. If a packet is sent in the PRACH packet, the mobile station will read the R/N part of the PCCF flag of the next P1FPDCH slot to determine whether the communication system successfully received the packet sent by the mobile station. For the first packet of random access, the mobile station will also read the CPE part of the PCCF flag to determine whether the specific access of the mobile station is captured. The communication system will set the value of the CPE flag to reflect the captured mobile station access. For example, the value of the CPE flag can be set to reflect the least important bit of the mobile station's identity. If the mobile station determines that its access has been captured based on the CPE flag and the R/N flag indicates that the packet has been received, the mobile station will check PEQ to determine whether it can continue its access using the current sub-channel. Up. If PEQ=PE_INT, the mobile station will continue to send out any additional packets it retains when the next P1 packet of PRACH starts.

As mentioned earlier, the PCCF flag provides mobile station information about when the mobile station is allowed to transmit, when it is required to transmit, the communication status of the previous transmission, and some echo related information. Since the PCCH channel may be a multi-rate channel (full speed, double speed, triple speed), many mobile stations may operate on channels that use different speeds. The PCCF calculation has the same transmission rate for all mobile stations. Therefore, the multi-rate PCCH does not have to be divided into dedicated bandwidths for full-speed, double-speed, and triple-speed transmission.

Figures 6 to 8 provide functional illustrations of several PEQ flags. Those skilled in the art should understand that these are only illustrative examples of the present invention, and the present invention is not limited to these descriptions. In Figures 12 to 14, the PEQ mark is used to describe the appropriate PEQ value in the transaction. In the case that the first random access cluster is successfully received, the communication system indicates R/N=received. In addition, the communication system will set PEQ=PE_INT to indicate that an uplink time slot under the same access path (subchannel) is reserved for the mobile station to transmit the second cluster.

Figure 6 is an example of a mobile station communicating on the full-speed PCCH. At the downlink time n, the mobile station Msl detects an idle state, and PEQ=50_INT at this time. At the downlink time n+1, the base station sets the channel as idle and no mobile station is in the process of acquiring the channel. At the uplink time n+1, the mobile station MSI sends out the first packet D1₁. When the downlink time is n+2, the base station sets the channel to be idle. At the downlink time n+3, the base station correctly receives the first packet D1₁According to the length indicator in the first cluster, it is determined that the complete data transmission should include four clusters. Therefore, the base station sets PEQ=PE_INT and R/N=received and the mobile station sends its next packet (D1₂). The mobile station MS1 immediately checks (explored) the PCCF of all sub-channels to find out that the mobile station can be used to operate and transmit the remaining packets Dl₃And Dl₄When PEQ=PE_INT and CPE=MS1. At the downlink time n+6, the base station indicates that it has received the cluster message Dl₂. At the downlink time n+7, the base station indicates that it has received the cluster message Dl₃. Finally, when asked n+8 on the downlink, the base station indicates that the cluster message Dl has been received₄. Therefore, all four clusters have been successfully received by the base station.

Figure 7 is an example of three mobile stations communicating on a full-speed PCCH. At the downlink time n, the base station sends the first cluster D3 to the third mobile station MS3. In addition, the first mobile station MSI detects the idle state (PEQ=SO_INT), and at the downlink time n+1, the second mobile station MS2 detects the idle state. Furthermore, at the downlink time n+1, the base station sends the second cluster D32 to the third mobile station MS3. At uplink time n+1, the first mobile station MS1 sends its first packet Dl_lTo the base station. At the downlink time n+2, the base station sends the third packet to the third mobile station MS3 and sets the channel to be idle. At the downlink time n+3, the base station sends the fourth cluster to the third mobile station MS3. In addition, the base station that has correctly received the first cluster of the MSI transmission determines that the complete transmission includes four clusters according to the length indicator in the cluster. Therefore, the base station sets PEQ=PE_INT and R/N=received as a response. At uplink time n+2, the mobile station MSZ sends its first cluster D2₁. At the downlink time n+4, the base station sends the fifth packet to the third mobile station MS3. In addition, the base station that has correctly received the first packet of MSZ transmission determines that the complete transmission includes a total of six bursts. Therefore, the base station sets PEQ=PE_INT and R/N=received as a response. At uplink time n+4, MS1 sends D1₂And MS1 sends D1 at uplink time n+5₂. At downlink time n+5, the base station indicates PEQ=PE_INT and PE=Msl, allowing D1₃It is transmitted in slot n+6 in the uplink time. At the downlink time n+6, the base station did not receive the cluster message D1 by setting R/N=not received indication₂. In addition, the base station instructs MS2 to continue to own the sub-channel by setting PEQ=No_INT. At the downlink time n+8, the base station indicates that it has received the cluster message D1 by setting R/N=received₃. In addition, the base station requires MSI to confirm its sub-channel ownership by setting PEQ=WA_INT. At the uplink time n+7, the third mobile station MS3 sends a cluster message as the result of receiving the reservation access request at the downlink time n+6. At downlink time n+9, the base station indicates that the cluster message sent by the third mobile station MS3 has been correctly received by setting R/N=received. Since this is a scheduled access rather than a random access, no PE matching is required. In addition, the base station indicates that the sub-channel has been re-assigned to MS2 by setting PEQ=PE_INT and PE=MS2. At uplink time n+8, the mobile station MSZ sends its cluster D2₃. At the uplink time n+9, the first mobile station resends its third packet D1₂. The mobile station will send out D2 when the uplink time is 11+10, n+11, n+12₄, D2₅, D2₆. Finally, at the uplink time n+12, the first mobile station MS1 sends D1₄。

Figure 8 is an example of a mobile station communicating on the triple-speed PCCH. In this example, the base station establishes an access opportunity by setting PEQ=50_INT. At the downlink time n, the mobile station MSI detects an idle condition. When n+1 is in the uplink, the mobile station MS1 sends its first packet Dl_l. In time slot 1 when the downlink time is n+3, the base station that has correctly received the first cluster of messages determines that the complete transmission unit contains 4/4 Dl through the length indicator in the cluster._lA cluster of news. In response, the base station sets PEQ=PE_INT and R/N=received for time slot 1. In slots 2 and 3 of downlink time n+3, the base station also sets PEQ=PE_INT and PE=MSI to designate the other two sub-channels for MSI. At the uplink time n+4, the mobile station MSI sends out its remaining cluster D1₂, D1₃And D1₄. At downlink time n+6, the base station has correctly received D1 by setting R/N=received in time slot 1-3₂, D1₃And D1₄。

According to a specific embodiment of the present invention, a packet random access channel (PRACH) is divided into sub-channels. Each sub-channel will add a delay between communications to allow the mobile station and the base station to have enough processing time in the joint random access event. Therefore, the more sub-channels the PRACH is divided into, the longer the delay. As far as encapsulated data is concerned, the transmission must happen very quickly. Therefore, the full-speed PCCH is defined as a combination of three PRACH sub-channels instead of the six sub-channels in the DCCH such as IS-136.

The PCCF flag is carried in the FPCCH time slot and is used to indicate the reception status of the cluster message previously transmitted on the RPCCH. The PCCF flag is also used to indicate the availability status of their corresponding RPCCH clusters. A mobile station with an access delay will read the PCCF flag to determine when to start an access attempt.

If there is a full-speed PCCH, its RPCCH cluster and FPCCH time slots will be multiplexed to establish three different access paths as shown in Figure 4. Assuming that FPCCH path 1 (p1) indicates that the next P1 cluster of RPCCH is available (that is, idle) and is selected as an access attempt, the mobile station will start receiving the complete P1 of FPCCH for a fixed time slot (24.8 ms ) And then start to transmit the first cluster of its access. "The mobile station will then begin to read the PCCF flag of the next PIFPCCH slot (21.8 ms) after completing its access to the cluster to determine its initial access The receiving state of the cluster at the base station. Different from Figure 4, Figure 9 depicts the sub-channels used in the full-speed DCCH according to IS-136. It is obvious from the comparison of Figure 10 and Figure 15 that in IS-136 It takes twice as long to transmit three packets (indicated by arrows). The same advantages can be obtained in double and triple PCCH.

It should be noted that the PCCF information carried in any designated FPCCH time slot has nothing to do with the carried third layer information. Therefore, the bandwidth occupied by the PCCF flag is completely separate from those designated for PBCCH, PPCH or PARCH.

For completeness, a detailed description of some components of the radio communication system will now be provided. FIG. 10 represents a block diagram of an example of a cellular radio telephone system, including an example base station 110 and a mobile station 120. The base station includes a control and processing unit 130, which is connected to the MSC 140, which in turn is connected to the PSTN (not shown in the figure). The general situation of this cellular radio telephone system has long been known to professionals in the field. For example, the aforementioned US patent application and US Patent No. 5,175,867, granted to Wejke et al. "Adjacent-Assistance in Cellular Communication System "Transfer", and the "Multi-Mode Signal Processing" in the U.S. Patent Application No. 07/967,027, both of which are mentioned here for reference.

The base station 110 processes multiple voice channels through the voice channel transceiver 150 controlled by the control and processing unit 130. Similarly, each base station includes a control channel transceiver 160, which can handle more than one control channel. The control channel transceiver 160 is controlled by the control and processing unit 130. The control channel transceiver 160 broadcasts control information on the control channel of the base station or cell to the mobile station that locks the control channel. It can be known that the transceivers 150 and 160 can be implemented as a single device, similar to the voice and control transceiver 170, to be used in DCC, DTC, and PCCH that share the same radio carrier frequency.

The mobile station 120 receives the information broadcast on the control channel in its voice and control channel transceiver 170. Immediately, the processing unit 180 evaluates the received control channel information, including the cell characteristics that the mobile station can lock, and determines which cell the mobile station should lock. Advantageously, the received control channel information not only contains absolute information about the cell to which it corresponds, but also contains relative information related to other cells adjacent to the cell corresponding to the control channel. For example, US Patent No. 5,353,333 granted to Raith et al. "Methods and devices for communication control of radio telephone systems" are mentioned here for reference.

Therefore, the encapsulated data calculation provided by the present invention can provide many benefits and advantages to those skilled in the art. For example, the PEQ encoding architecture according to the present invention can operate in the existing IS-136 physical layer field architecture (that is, no new fields are required and the existing feedback function is maintained at a high level). Furthermore, the existing BRI field of the IS-136 physical layer is released to re-specify other functions required.

The specific embodiments of the present invention also allow contention-based access architecture (such as time slot ALOHA or CSMA) and multiplexing functions (reservation-based access) to operate simultaneously on the uplink of the same TDMA channel. More specifically, the present invention allows the delay to be applied equally to all users of the packet data system on the same TDMA channel regardless of load (that is, to multiplex all users fairly with equal output delay).

The present invention also provides a mechanism for the base station to quickly detect and effectively recover the suspicious sub-channel interception status (that is, to effectively transmit the encapsulated data of the uplink).

However, those skilled in the art can understand that the present invention can be implemented in other specific forms without departing from its spirit and basic characteristics. Therefore, the embodiments disclosed herein are only for related descriptions and not for limitation purposes. The scope of the present invention is indicated by the following patent application scope, rather than limited by the foregoing description. Therefore, any changes within the meaning and equivalent scope of this case shall be deemed to be covered by the scope of the present invention.

The first figure (a) shows an example of a forward DCCH set as a continuous time slot included in a continuous time slot transmitted on a carrier frequency;

The first figure (b) shows an example of the time slot format of the IS-136 DCCH column;

The second picture shows the logical channel of D-AMPS;

The third figure is an example of a possible sequence of correspondences between different levels in a radio communication system;

The fourth figure shows the PRACH sub-channel used in the full-speed PCCH;

The fifth picture is an example of the dialogue between the mobile station and the communication system;

The sixth picture shows the communication of a mobile station on PCCH at full speed;

The seventh picture shows the communication of the three mobile stations on PCCH at full speed;

The eighth picture shows the communication of a mobile station on the triple-speed PCCH;

The ninth figure is the DCCH sub-channel on the full-speed DCCH according to IS-136; and

Figure 10 is an example of radio communication system components that can be used to implement the present invention.