WO2007095778A1

WO2007095778A1 - A realization method for improving the transmission rate of general packet radio service

Info

Publication number: WO2007095778A1
Application number: PCT/CN2006/000278
Authority: WO
Inventors: Xue Tang; Ji Hong Wang
Original assignee: Zte Corporation
Priority date: 2006-02-27
Filing date: 2006-02-27
Publication date: 2007-08-30

Abstract

A realization method for improving the transmission rate of general packet radio service includes the following steps: ordering the size of send window for each down temporary block flow of General Packet Radio Service; carrying out data transfer in the wireless link control confirm mode according to the determinate window size; carrying out confirming bit map processing in the wireless link control confirm mode according to the determinate window size. The method of present invention can self-adjust RLC moving window in the BSS system according to system delay, thus can improve transmission rate under the fixed Abis delay condition furthest, and can make GPRS transmission rate reach the most rate under Abis condition thus improves channel utilization ratio, in turn raises improves GPRS transmission rate greatly and can satisfy client's require to the full..

Description

Method for improving transmission rate of wireless packet data service

The invention relates to a method for improving the transmission rate in a GPRS system, in particular to improving the transmission rate of wireless packet data services under the condition of satellite Abis transmission in the field of GSM (Global System for Mobile communication) mobile communication technology. An implementation method. Background technique

The GEO geostationary orbit system satellite is located on the geosynchronous equator near the Earth's equator at 35,786 km. Its one-way transmission delay is between 230 and 270 ms, and the round-trip time is extended by 540 ms. When the Abis interface in the GPRS (General Packet Radio Service) system, that is, the interface between the base station controller and the base station, uses satellite transmission, it will have a great impact on the transmission rate of GPRS. The specific analysis is as follows:

In the GPRS system, the RLC (Radio Link Control) layer adopts a selective resending sliding window mechanism, and its efficiency depends on three factors: window size (Windowsize), bandwidth (Bandwidth) and system two-way delay (Delay). The bandwidth is proportional to the multi-slot capability of the handset. For ease of analysis, the window size is in blocks, the bandwidth is in blocks / 20ms, and the system delay is in units of 20ms.

In delay D, the total number of blocks that the sender can transmit is equal to:

BlockNum (Delay) = BandwidthxDelay

Line utilization R is equal to:

1, when WindowSize> BlockNum (Delay)

R=l;

2, when WindowSize<BlockNum (Delay)

R= Windowsize/ BlockNum (Delay) ; (Formula 1)

It is further concluded that the relationship between the actual transmission rate and the theoretical rate under satellite Abis conditions is:

V=Vt (theoretical rate) xR;

In the GPRS system, the protocol specifies Windowsize=64, the two-way delay introduced by the satellite ABIS is about 600ms, the original system delay is about 200ms, and the total delay is about 800ms, Delay=800/20ms=40. The relationship between rate and bandwidth is shown in Table 1:

Confirmation 1 1 100 % (BlockNum is the same as the original system

(Delay) = 40xl<64) CS-1: 9.6

CS-2: 13.4

CS-3: 15.6

CS-4: 21.4

2 2 64/80=80% CS-1: 15.36

CS-2: 21.44

CS-3: 24.96

CS-4-.34.24

3 3 64/120=53 % CS-1: 15.36

CS-2: 21.44

CS-3: 24.96

CS-4:34.24

4 4 64/160=40% CS-1:15.36

CS-2: 21.44

CS-3: 24.96

CS-4:34.24 Table 1

It can be seen that under the satellite Abis condition, the transmission rate reaches a maximum at two time slots, and the rate does not increase as the bandwidth increases to more than two time slots.

This is because when BlockNum (Delay) > Windowsize: Vsatellite = Vtx N 64/Nx40= where N = slot width, N appears in both the numerator and the denominator, the effect is eliminated, so it can be concluded that the satellite Abis condition If the sliding window mechanism is not modified, the maximum rate that can be reached is the maximum rate of two time slots. The prior art cannot break the limitation of the window size, and the RLC sliding window size in the BSS (Base Station System) system cannot be automatically adjusted according to the system delay, thereby causing the channel utilization to be very low, the transmission rate to be slow, and the timeliness not being met. Business needs. Summary of the invention

The object of the present invention is to provide an implementation method for improving the GPRS transmission rate under the condition of satellite Abis transmission. In the BSS system, the RLC layer transmission window size is automatically adjusted according to the Abis delay, thereby maximizing the transmission rate under the fixed Abis delay condition, thereby greatly improving the GPRS transmission rate.

In order to solve the above technical problem, the technical solution of the present invention includes:

An implementation method for improving a transmission rate of a wireless packet data service, comprising the following steps:

A. Customizing the sending window size for each downlink temporary block stream of the wireless packet data service;

B. Perform data transmission in the wireless link control confirmation mode according to the determined window size;

C. Acknowledge bitmap processing in the wireless link control confirmation mode according to the determined window size. The method further includes the following specific steps:

Al, timing detection Abis delay;

A2. Calculate the size of the sending window according to the number of allocated channels, the current Abis delay, and the associated reserved block period interval variable of the system customization.

The method further includes the following specific steps:

A21, calculating a delay window size;

A22, if the delay window size is greater than 64 and less than 128, the TBF window size ranges from - the TBF window size is greater than or equal to the delay window size and is less than or equal to 128;

A23. If the delay window size is less than or equal to 64, the TBF window size is equal to 64;

A24. If the delay window size is greater than or equal to 128, the TBF window size is equal to 128.

The method further includes the following specific steps:

When the transmitting end sends data, the relevant reserved block period bit is configured according to the block interval of the relevant reserved block period interval variable; C2, the transmitting end receives the downlink data response sent by the mobile phone, and performs related processing.

The method further includes the following specific steps:

C2 calculates the start value of the acknowledgement bitmap of the receiving end;

C22. Determine whether the receiving end confirms that the bitmap start value is within the range of the sending end window; if in the sending end window, the data between the bitmap starting value variable and the window starting value variable The block is configured to confirm the status, and proceeds to step C24; if outside the sending end window, proceeds to step C23;

C23. Calculate whether the last acknowledge block position variable value of the receiving end is within the range of the sending end window; if within the sending end window, move the sending end window forward by a predetermined position; if the last confirming block position The variable value is outside the range of the sender window, then proceeds to step C27;

C24. Calculate the window range of the receiving end. The specific formula is as follows:

Window start value variable WrBegin=last confirmation block position variable VQ;

Window range variable WrEnd= (VQ +64) % 128; C25. Determine whether the window range variable is located between the sending end confirmation bitmap start value variable and the sending end pointer variable; if the range is within the range, the sending end is between the window range variable and the sending end pointer variable. The data block status is configured as a non-confirmed block status and proceeds to step C26;

C26, end;

C27 releases the temporary block stream and ends the transmission.

The method further includes the following specific steps:

Delay window size calculation formula:

Delay window size = number of channels X delay (msy20 + related reserved block period interval variable).

The method further includes the following specific steps:

Calculating the calculation formula of the receiving end confirmation bitmap starting value:

BitmapBegin= (starting sequence number SSN—64+128) %128 .

The method further includes the following specific steps:

The calculation formula of the predetermined position-related reserved block period interval variable of the transmitting end window is: =|reserved block period interval variable =|last acknowledgment block position variable - bitmap start value variable.

The invention provides a method for realizing the GPRS transmission rate under the satellite Abis transmission condition. According to the characteristics that the downlink data traffic of the GPRS service itself is much larger than the uplink data traffic, the RLC sliding window size in the BSS system is automatically adjusted according to the system delay. The strategy of maximizing the transmission rate under the fixed Abis delay condition, so that the GPRS transmission rate under the satellite Abis condition reaches the maximum rate of 3 time slots, thereby greatly improving the channel utilization rate, thereby greatly improving the GPRS transmission rate. . DRAWINGS

1 is a schematic diagram of a core algorithm of the method of the present invention;

2 is a schematic diagram of the size of a custom downlink TBF transmission window of the method of the present invention

3 is a schematic diagram of an algorithm for calculating a transmission window size by the method of the present invention;

4 is a schematic diagram of an algorithm for confirming a bitmap of the method of the present invention;

FIG. 5 is a schematic diagram of a specific calculation algorithm for confirming a bitmap of the method of the present invention. detailed description

The preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

The method for improving the transmission rate of the wireless packet data service of the present invention introduces a mechanism that the RLC layer transmission window size is automatically adjusted with the Abis delay in the BSS system, thereby maximizing the transmission under the fixed Abis delay condition. Transmission rate.

The core algorithm of the present invention is shown in Figure 1, which includes the following steps:

1. Customize the send window size for each downlink TBF (Temprory Block Flow); wherein, this step shown in Figure 2 includes the following steps:

1, timing detection Abis delay Tdelay;

2. When the downlink TBF is established, the transmission window size W is calculated according to the allocated channel number, the current Abis delay, and the system-defined RRBP (Relative Reserved Block Period) interval Nrrbp. The specific calculation method is shown in Figure 3. Show, also includes the steps:

a, calculate the delay window size Wd;

Wd = number of channels χ delay (ms) / 20 + Nrrbp;

b. If the delay window size is greater than 64 and less than 128, the TBF window size ranges from:

Wd<=W<=128;

e. If the delay window size is less than or equal to 64, the TBF window size is equal to 64;

d. If the delay window size is greater than or equal to 128, the TBF window size is equal to 128;

2. Data transmission in the RLC confirmation mode according to the determined window size;

3. Confirm the bitmap processing in the RLC confirmation mode according to the determined window size; wherein, as shown in Figure 4, this step further includes the following steps -

1) When the transmitting end sends data, the relevant reserved block period bits are both RRBP bits according to the Nrrbp block interval;

2) The sender receives the downlink data response sent by the mobile phone and performs related processing.

In addition, as shown in FIG. 5, this step further includes the following steps:

a) Calculate the start value of the acknowledgement bitmap at the receiving end -

BitmapBegin= (starting sequence number SSN—64+ 128) 128;

b) judging whether the receiving end confirms that the starting value of the bitmap is within the range of the transmitting window, and if it is in the transmitting window, the data block between the bitmap starting value variable VA and the window starting value variable WrBegin is set to Confirm the status, go to step Mountain if it is outside the sending end window, then go to step c;

c) Calculate whether the VQ value of the last confirmation block position variable of the receiving end is within the range of the transmitting end window. If it is within the range of the sending end window, move the sending end window forward by a predetermined position. Nforward, Nforward is calculated as follows -

Nforward =|VQ-VA|;

If the VQ value is outside the range of the sender window, go to step g;

d) Calculate the range of the receiving window, the specific formula is as follows:

Window start value variable WrBegin- VQ; Window range variable WrEnd- (VQ +64) % 128;

e) determining whether WrEnd is located between the transmitting end VA and the transmitting pointer variable VS. If it is within the range, the transmitting end sets the data block state between WrEnd and VS to a non-confirmed block state, and the NACK state proceeds to step f. ;

End of 0;

g) Release this TBF and end this transmission.

In summary, according to the characteristics that the downlink data traffic of the GPRS service itself is much larger than the uplink data traffic, the method for automatically adjusting the RLC sliding window size according to the system delay in the BSS system is used to maximize the fixed Abis delay condition. The transmission rate makes the GPRS transmission rate of the satellite Abis condition reach the maximum rate of 3 time slots, thereby greatly improving the channel utilization rate and thus the GPRS transmission rate.

The method for improving the GPRS transmission rate under the condition of satellite Abis transmission provided by the present invention, for example, when the downlink multi-slot capability of the mobile phone is 3 time slots, and the RRBP interval selected by the system is 5 blocks, According to the strategy of automatically adjusting the RLC sliding window size in the BSS system according to the present invention, the transmission window size of the downlink TBF can be customized to 128, and the line utilization rate is equal to 1, and the downlink TBF transmission rate is the highest. Up to 34.24 Kbps, the transmission rate is greatly improved. This example also fully demonstrates that the present invention greatly improves the GPRS downlink transmission rate under the satellite Abis transmission condition.

It should be understood that the above description of the preferred embodiments is not to be construed as limiting the scope of the invention.

Claims

Rights request

An implementation method for improving a transmission rate of a wireless packet data service, comprising the steps of: A. customizing a transmission window size for each downlink temporary block stream of the wireless packet data service;

C. Perform acknowledgment bitmap processing in the wireless link control confirmation mode according to the determined window size.

The implementation method according to claim 1, wherein the step A further comprises: Al, periodically detecting the Abis delay;

The implementation method according to claim 2, wherein the step A2 further includes:

A21, calculating a delay window size;

A22, if the delay window size is greater than 64 and less than 128, the TBF window size ranges from: the TBF window size is greater than or equal to the delay window size and is less than or equal to 128;

The implementation method of claim 1, wherein the step C further comprises: configuring the relevant reserved block period bits according to the block interval of the relevant reserved block period interval variable when the transmitting end sends the data;

C2: The sender receives the downlink data response sent by the mobile phone, and performs related processing.

The implementation method of claim 4, wherein the step C2 further comprises: C21: calculating, by the receiving end, a bitmap start value;

C22. Determine whether the receiving end confirms that the bitmap start value is within the range of the sending end window; if in the sending end window, the data between the bitmap starting value variable and the window starting value variable The block is configured to confirm the status, proceeds to step C24; if outside the sending end window, proceeds to step C23;

C23. Calculate whether the last acknowledge block position variable value of the receiving end is within the range of the sending end window; if within the sending end window range, move the sending end window forward by a predetermined position; if the last confirming block position The variable value is outside the range of the sender window, then proceeds to step C27;

Window start value variable WrBegin - last confirmation block position variable VQ;

Window range variable WrEnd- (VQ +64) % 128;

C25. Determine whether the window range variable is located at the sending end to confirm the bitmap start value variable and the sender end pointer variable. If in this range, the sender configures the data block state between the window range variable and the sender pointer variable to the non-confirmed block state and proceeds to step C26;

C26, end;

C27. Release the temporary block stream, and end the transmission.

The implementation method according to claim 3, wherein the step B21 further comprises: a delay window size calculation formula:

Delay window size = number of channels X delay (ms) / 20 + associated reserved block period interval variable.

The implementation method according to claim 5, wherein the step C21 further comprises: calculating a calculation formula of the receiving end confirmation bitmap starting value:

BitmapBegin= (starting sequence number SSN—64+128) % 128 .

The implementation method according to claim 5, wherein the step C23 further comprises: calculating, by the transmitting end window, a calculation formula of a predetermined position related reserved block period interval variable: The =|last confirmation block position variable of the variable - the bitmap start value variable.