CN1508993A - A channel coding method for multi-user reception in WCDMA system - Google Patents

Abstract

The invention proposes a channel coding method for multi-user reception in a wideband code division multiple access (WCDMA) system, and the method is a channel coding method for a dedicated physical data channel (DPDCH) of a 12.2 kbps uplink dedicated physical channel. In the case of increasing the spreading factor and reducing the complexity of the encoder and decoder, the method keeps the detection performance of the dedicated physical data channel (DPDCH) and the dedicated physical control channel (DPCCH) of the multi-user receiving device and slightly improves improve.

Description

A channel coding method for multi-user reception in WCDMA system

Technical field

The invention relates to a communication system, in particular to a channel coding technique for an uplink dedicated physical channel in a wideband code division multiple access (WCDMA) cellular mobile communication system and a multi-user detection technique for a base station.

Background technique

The agreement of 3GPP brings together a complete set of standards of WCDMA system. According to the 3GPP protocol, the information bits of the dedicated physical data channel (DPDCH) in the uplink dedicated physical channel are channel-coded first, and then binary phase-shift keying (BPSK) mapping and spectrum spreading are performed. The information bits of the dedicated physical control channel (DPCCH) are directly mapped and spread by BPSK, and the spreading factor is 256. The spread-spectrum DPDCH channel chip and DPCCH channel chip constitute I and Q two-way data, which are scrambled together. The scrambled I and Q chips are respectively pulse-shaped, and then sent to the base station through carrier modulation. In the 25.104, 25.944 and 25.212 protocols of 3GPP, the channel coding method of the DPDCH channel in the uplink dedicated physical channel is stipulated. See the 25.213 protocol of 3GPP for the spreading, scrambling, pulse shaping and modulation methods of the uplink dedicated physical channel.

The above is the process of the user end (UE) sending bits on the uplink dedicated physical channel in the WCDMA system. The reception of the bits sent by the UE on the uplink dedicated physical channel at the base station of the WCDMA system may adopt the RAKE reception technology. The device of the RAKE receiving technology is shown in FIG. 1 . However, the receiving performance of traditional single-user RAKE receivers decreases when the number of users increases and the near-far effect occurs.

Multi-user detection technology is an enhanced technology to overcome the influence of multiple access interference and improve the capacity of WCDMA system. It performs joint detection on multiple user signals, thereby reducing the impact of multiple access interference on the performance of the receiver as much as possible, and improving the capacity of the system. Document [1] proposes a multi-user receiving device for uplink dedicated physical channel with patent application number 02151067.9. The device adopts multi-user detection technology and applies the simplified method of double-layer weighted parallel interference cancellation method to uplink dedicated physical channel The signal reception has higher performance than the traditional single-user RAKE receiving device.

Fig. 2 shows an existing uplink dedicated physical channel multi-user receiving device. It can be seen from FIG. 2 that the multi-user receiving device 200 includes a demodulation and matched filter 201, a multipath searcher group 205, a first-stage parallel interference cancellation (PIC) structure 202 and a last-stage PIC structure 204, and also includes Intermediate levels of PIC structure 203 . The device first demodulates and matches the received signal of the antenna to obtain the baseband signal, and simultaneously sends the baseband signal to the multipath searcher group 205, the first stage PIC structure 202, the intermediate stage PIC structure 203 and the last stage PIC Structure 204.

As shown in Figure 2, the baseband signal enters the multipath searcher group. If there are K users in the system, there are K multipath searchers in the multipath searcher group. Each searcher is responsible for searching the path delay information of a user. The path delay information of all users is sent to the first-level PIC structure 202 , the middle-level PIC structure 203 and the last-level PIC structure 204 at the same time.

FIG. 3 shows the first-level PIC structure of an existing uplink dedicated physical channel multi-user receiving device. The first-level PIC structure 202 is composed of K user signal processing units 300 and one interference cancellation unit 320 . Each user corresponds to a user signal processing unit 300 . The signal processing unit 300 of each user performs exactly the same function. As shown in FIG. 3 , the baseband signals entering the first-stage PIC structure 202 enter the signal processing unit 300 of each user in parallel. The multipath delay information of each user entering the first-level PIC structure 202 enters the signal processing unit 300 of the corresponding user respectively.

As shown in Figure 3, the user signal processing unit 300 includes a DPDCH despreading unit 301, a DPCCH despreading unit 302, a power control unit 303, a channel estimation unit 304, a noise power estimation unit 308, a DPDCH RAKE combination unit 305, a transmission format combination Indication (TFCI) decoding unit 306 , DPCCH RAKE merging unit 307 , DPDCH soft decision and soft decision weighting unit 309 , DPCCH soft decision and soft decision weighting unit 310 and signal regeneration unit 311 . The interference cancellation unit 320 includes a signal summing device 321 , a shaping and matched filtering unit 322 and a residual calculation unit 323 . The user signal processing unit 300 obtains the user's power control command, symbol-level regenerated signal and chip-level regenerated signal through a series of processing from the input baseband signal and the user's multipath delay information. The user's power control instructions are respectively fed back to the user equipment (UE) at the sending end via the downlink, and the UE adjusts the uplink transmission power according to the power control instructions. The user's symbol-level regenerated signal is sent to the symbol correction subunit in the user signal processing unit of the same user in the next-level PIC structure. The chip-level regenerated signals and baseband signals of all users enter the interference cancellation unit 320, which processes the input signals to obtain residual signals. The residual signal is sent to the next-level PIC structure as an output signal of the current-level PIC.

Fig. 4 shows the intermediate stage PIC structure of the existing uplink dedicated physical channel multi-user receiving device. The intermediate-level PIC structure 203 still includes K user signal processing units 400 and an interference cancellation unit 420 . Each user corresponds to a user signal processing unit 400 . The user signal processing unit 400 of each user performs exactly the same function. The intermediate stage PIC structure 203 also includes a spreading factor calculation unit 430 . The number of stages of the intermediate-level PIC structure 203 can be determined as required, and one or more intermediate-level PIC structures 203 can be used, or no intermediate-level PIC structure 203 can be used.

As shown in Figure 4, the user signal processing unit 400 includes a DPDCH despreading unit 401, a DPCCH despreading unit 402, a channel estimation unit 403, a noise power estimation unit 404, a symbol modification unit 405, a symbol modification unit 406, and a DPDCH RAKE merging unit 407 , DPCCH RAKE merging unit 408 , DPDCH soft decision and soft decision weighting unit 409 , DPCCH soft decision and soft decision weighting unit 410 , and signal regeneration unit 411 . The interference cancellation unit 420 includes a signal summation device 421 , a shaping and matched filtering unit 422 and a residual calculation unit 423 . In the intermediate stage PIC structure 203, the input signal of the user's signal processing unit 400 is the residual signal, the symbol-level regenerated signal of the user and the path delay information of the user. The output is the user's symbol-level regenerated signal and chip-level regenerated signal. The symbol-level regenerated signal is sent to the symbol correction subunit in the signal processing unit of the same user in the subsequent PIC structure, and the chip-level regenerated signal is sent to the interference cancellation unit 420 . The baseband signal also enters the interference cancellation unit. This unit processes the chip-level regenerated signals and baseband signals of all users to obtain residual signals. The residual signal is sent to the next-level PIC structure as an output signal of the current-level PIC. The PIC structure processing process of other subsequent levels at this level is the same.

Fig. 5 shows the last stage PIC structure of the existing uplink dedicated physical channel multi-user receiving device. The last stage PIC structure 204 includes K user signal processing units 500 and also includes a spreading factor calculation unit 510 . Each user corresponds to a user signal processing unit 500 . The user signal processing unit 500 of each user performs exactly the same function. As shown in Figure 5, the user's signal processing unit 500 includes a DPDCH despreading unit 501, a DPCCH despreading unit 502, a channel estimation unit 503, a symbol modification unit 504, a symbol modification unit 505, a DPDCH RAKE combining unit 506, and a DPCCH RAKE Combining unit 507 , channel decoder 508 and hard decision unit 509 . The user's multipath delay information and the residual signal of the upper-level PIC structure enter the DPDCH processing channel and the DPCCH processing channel in the signal processing unit 500 at the same time. The DPDCH channel first performs DPDCH despreading on the input residual signal, and then performs symbol correction and multipath combination on the despreading result. The result is sent to the channel decoder 508 of the DPDCH channel, and the information bits sent by the DPDCH channel are obtained through channel decoding. The DPCCH channel first performs DPCCH despreading on the input residual signal, then performs symbol correction and channel estimation on the despreading result, and finally performs multipath combination. The multipath combination result is sent to the hard decision unit 509 of the DPCCH channel. The hard decision unit 509 performs hard decision on the input signal to obtain the information bits sent by the DPCCH channel.

In the middle-level PIC structure 203 and the last-level PIC structure 204, DPDCH despreading needs to know the spreading factor of DPDCH, and the spreading factor can use the spreading factor of the DPDCH despreading unit in the previous level of PIC structure; The spreading factor calculation unit is obtained by decoding the TFCI of the RAKE combining result of the DPCCH channel of the current stage. The spreading factor calculation unit includes a TFCI decoding unit.

The above is the signal processing process of the multi-user receiving device for the uplink dedicated physical channel. The simplified method of the double-layer weighted parallel interference cancellation method adopted by the device not only ensures the minimum judgment cost, but also makes up for the deviation of the user signal estimation in the statistical sense through partial interference cancellation, which greatly improves the performance. The complexity of layer weighted parallel interference cancellation method is reduced.

In the multi-user receiving device of the above-mentioned uplink dedicated physical channel, only the processing process of the DPDCH channel is considered. When the signal-to-noise ratio of the RAKE combination result of the user at the current level is high, the soft decision result of the RAKE combination is more accurate, and the user's symbol-level regenerated signal and chip-level regenerated signal are more accurate, so the interference cancellation performance of the current level The better, which makes the performance of the next level of PICs correspondingly better. When the signal-to-noise ratio of the RAKE combination result of the user at the current level is low, the reliability of the soft decision result of the RAKE combination decreases, and the user's symbol-level and chip-level regenerated signals are inaccurate, so the interference cancellation performance of the current level is limited. Reduced, which makes the performance of the next level of PIC will be reduced accordingly. Therefore, improving the signal-to-noise ratio of the user RAKE combination result can improve the performance of the multi-user receiving device. The performance here refers to the demodulation bit error rate of the user DPDCH channel.

However, the index to measure the detection performance of the user DPDCH channel is the block error rate of the user DPDCH channel. The block error rate is not only related to the user's demodulation performance, but also closely related to the decoding depth and coding rate of the user's decoder. That is, the block error rate of the user DPDCH channel not only depends on the demodulation performance of the user DPDCH channel, but also depends on the error correction capability of the DPDCH channel decoding method.

For the uplink dedicated physical channel in the WCDMA system, increasing the spreading factor of the user DPDCH channel can improve the signal-to-noise ratio of the RAKE combination result of the user DPDCH channel. However, since the chip rate at the sending end of the WCDMA system is 3.84*10 ⁶ cps, the sum of the coding gain and the spreading gain of the DPDCH channel is definite. When the spreading gain is increased, the coding gain is reduced, which means that the coding complexity is reduced and the error correction capability of the decoder is reduced. Therefore, when the spreading factor is increased to improve the demodulation performance of the user's DPDCH channel, it does not necessarily improve the block error rate performance of the user's DPDCH channel.

Fig. 6 shows the channel coding method of the 12.2kbps uplink dedicated physical channel in the existing WCDMA protocol. In the 25.212 and 25.104 protocols of 3GPP, the DPDCH channel coding method of the 12.2kbps uplink dedicated physical channel is stipulated. As shown in Figure 6, in the 12.2kbps uplink dedicated physical channel, CRC bit addition, tail bit addition, 1/3 rate convolutional coding, first interleaving, wireless frame segmentation and rate matching are performed on the DTCH channel and DCCH channel respectively. Then, the data of these two channels are multiplexed together for the second interleaving and time slot division. Under this encoding method, the spreading factor of the DPDCH channel is 64. The block diagram of the 1/3 rate convolution encoder is shown in the protocol 25.212; the rate matching adopts the uniform repetition method. In this encoding method, see protocol 25.212 for the specific methods of the first interleaving, wireless frame division, rate matching, data multiplexing, second interleaving and time slot division.

Table 1 is a parameter table of the channel coding method of the 12.2kbps uplink dedicated physical channel in the existing WCDMA protocol: parameter standard unit information bit rate 12.2 kbps Dedicated Physical Channel (DPCH) 60 kbps Power Control close Transport Format Combination Indicator (TFCI) open repetition rate twenty two %

In the WCDMA system, the process of sending information bits in the 12.2 kbps uplink dedicated physical channel at the UE side is as described above for the information bit sending process of the uplink dedicated physical channel. In the transmission process, the DPDCH channel is coded by using the channel coding method shown in FIG. 6 , and the DPDCH channel is spread by a spreading factor of 64.

The base station of the WCDMA system uses the above-mentioned multi-user receiving device to receive the information bits sent by the UE on the 12.2kbps uplink dedicated physical channel, and the receiving process is as described above. When decoding the DPDCH channel, the decoding is performed according to the reverse process of the encoding process shown in FIG. 6 .

Studies have shown that the channel coding method of the existing 12.2kbps uplink dedicated physical channel in the WCDMA protocol shown in Figure 6 is not optimal in a multi-user receiving device, and the channel coding method can be improved. The present invention proposes a channel coding method for multi-user reception aimed at the 12.2kbps uplink dedicated physical channel. The method reduces the complexity of the encoder and decoder while maintaining and slightly improving the performance of multi-user detection .

Contents of Invention

The purpose of the present invention is to provide a channel coding method for multi-user reception in a WCDMA system for the 12.2kbps uplink dedicated physical channel, the coding method makes the spreading factor of the user's DPDCH channel improved, and by using the coding method, The multi-user receiving device maintains and slightly improves the detection performance of the user's DPDCH channel and DPCCH channel under the condition that the complexity of the encoder and the decoder is reduced.

The present invention is realized by following method, and this method comprises the following steps:

First, add cyclic redundancy check (CRC) bits, tail bits, 1/2 rate convolutional coding, first interleaving, and wireless frame segmentation to the dedicated traffic channel (DTCH) signal and dedicated control channel (DCCH) signal respectively. and rate matching; then the data of the DTCH channel signal and the DCCH channel signal are multiplexed together, and the second interleaving and time slot division are performed to form a dedicated physical data channel (DPDCH) signal.

Wherein the 1/2 rate convolution coding operates according to the provisions in the 25.212 protocol of 3GPP. The first interleaving, radio frame division, rate matching, data multiplexing, second interleaving and time slot division all operate according to the regulations in the 25.212 protocol of 3GPP. The rate matching adopts the rate matching method in the 25.212 protocol of 3GPP, and in this method, the rate matching adopts a uniform punching method.

The spreading factor of the DPDCH channel signal is set to 128 by using the above channel coding method.

The present invention greatly improves the spreading factor of the DPDCH channel signal by adopting 1/2 rate convolution coding, and the present invention enables the multi-user receiving device to The detection performance is maintained and slightly improved.

Description of drawings

FIG. 1 is a schematic diagram of an existing uplink dedicated physical channel single-user RAKE receiving device;

FIG. 2 is a schematic diagram of an existing uplink dedicated physical channel multi-user receiving device;

FIG. 3 is a schematic structural diagram of a first-stage PIC in an existing uplink dedicated physical channel multi-user receiving device;

4 is a schematic structural diagram of an intermediate-level PIC in an existing uplink dedicated physical channel multi-user receiving device;

Fig. 5 is a schematic diagram of the structure of the last stage PIC in the existing uplink dedicated physical channel multi-user receiving device.

6 is a schematic diagram of a channel coding method for a 12.2kbps uplink dedicated physical channel in an existing WCDMA protocol;

Fig. 7 is the schematic diagram of the spreading and scrambling process of the 12.2kbps uplink dedicated physical channel in the existing WCDMA protocol;

FIG. 8 is a schematic diagram of a channel coding method for a 12.2 kbps uplink dedicated physical channel according to the present invention.

Detailed ways

The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

At the sending end of the WCDMA system, the user equipment (UE) sends information bits on the 12.2kbps uplink dedicated physical channel according to the following procedures:

The information bits of the dedicated physical data channel (DPDCH) are channel-coded first, and then BPSK-mapped, and the information obtained by BPSK mapping is spread according to the spreading factor of the DPDCH channel obtained by channel coding. However, the information bits of the DPCCH channel are directly subjected to BPSK mapping and spreading, and the spreading factor is 256. Fig. 7 shows a schematic diagram of the spreading and scrambling process of the 12.2kbps uplink dedicated physical channel in the existing WCDMA protocol. As shown in FIG. 7 , the spread-spectrum DPDCH channel chips and DPCCH channel chips constitute I and Q two-way data, which are scrambled together. The scrambled I and Q chips are respectively pulse-shaped, and then sent to the base station through carrier modulation. See the 25.213 protocol of 3GPP for the spreading, scrambling, pulse shaping and modulation methods of the uplink dedicated physical channel.

In order to obtain a higher spreading factor of the DPDCH channel, the present invention proposes a channel coding method for multi-user reception in a WCDMA system, comprising the following steps:

Firstly, under the 12.2kbps dedicated physical channel, cyclic redundancy check (CRC) bit addition, tail bit addition, 1/2 rate convolutional coding, The first interleaving, wireless frame division and rate matching; then the data of the DTCH channel signal and the DCCH channel signal are multiplexed together, and the second interleaving and time slot division are performed to form a dedicated physical data channel (DPDCH) signal.

Wherein the 1/2 rate convolution coding operates according to the provisions in the 25.212 protocol of 3GPP. The first interleaving, radio frame division, rate matching, data multiplexing, second interleaving and time slot division all operate according to the regulations in the 25.212 protocol of 3GPP. The rate matching adopts the rate matching method in the 25.212 protocol of 3GPP, and specifically adopts the uniform punching method.

The spreading factor of the DPDCH channel signal is set to 128 by using the above channel coding method.

Table 2 is the parameter table of the channel coding method of the 12.2kbps uplink dedicated physical channel of the present invention: parameter standard unit information bit rate 12.2 kbps Dedicated Physical Channel (DPCH) 30 kbps Power Control close Transport Format Combination Indicator (TFCI) open Hole rate 8.5 %

Fig. 8 shows a specific example of implementing the channel coding method of the 12.2kbps uplink dedicated physical channel of the present invention. As shown in Figure 8, the following steps are included:

a. Under the 12.2kbps dedicated physical channel, 16-bit CRC bits are added to the DTCH channel signal, that is, 244-bit information data to form a 260-bit signal, and at the same time, 12-bit CRC is performed on the DCCH channel signal, that is, 100-bit information data After the bits are added, a 112-bit signal is formed;

b. Carry out 8-bit tail bit addition to the 260-bit DTCH channel signal after the CRC bit addition to form a 268-bit signal, and simultaneously perform 8-bit tail bit addition to the 112-bit DCCH channel signal after the CRC bit addition to form a 120-bit signal signal of;

c. Perform 1/2 rate convolutional encoding on the 268-bit DTCH channel signal after the tail bit is added to form a 536-bit signal, and at the same time perform 1/2 rate convolutional encoding on the 120-bit DCCH channel signal after the tail bit is added to form 240-bit signal;

d. The 536-bit DTCH channel signal after the 1/2 rate convolution encoding is interleaved for the first time, that is, the bit arrangement order of the signal is changed, and the 240-bit DCCH channel signal after the 1/2 rate convolution encoding is interleaved for the first time One interleaving is to change the bit sequence of the signal;

e. Carry out wireless frame segmentation to the 536-bit DTCH channel signal after the first interleaving to form a 2-frame signal with a size of 268 bits, and perform wireless frame segmentation to form a size of 240-bit DCCH channel signal after the first interleaving. 60-bit 4-frame signal;

f. Use the uniform punching method to perform rate matching on the 2-frame DTCH channel signal with a frame size of 268 bits after wireless frame segmentation, and delete some bits to form a corresponding 2-frame signal with a frame size of 244 bits; at the same time, use uniform The punching method performs rate matching on the 4-frame DCCH channel signal with a size of 60 bits per frame after the wireless frame is divided, and knocks out some bits to form a 4-frame signal with a size of 56 bits per frame;

g. Multiplexing the data of the rate-matched DTCH channel signal and the DCCH channel signal together to form a 2-frame signal with a size of 300 bits, and performing the second interleaving; and performing time slotting on the 4-frame signals after the second interleaving The division forms a dedicated physical data channel (DPDCH) signal, and each frame signal is divided into signals with a size of 20 bits and a number of time slots of 15.

At the base station of the WCDMA system, the multi-user receiving device shown in Figure 2 to Figure 5 is used to receive the information bits sent by the UE on the 12.2kbps uplink dedicated physical channel. The specific receiving process is as follows:

As shown in FIG. 2 , the received signal of the antenna is demodulated and processed by a matched filter 201 to obtain a baseband signal, and the baseband signal is simultaneously sent to the multipath searcher group 205 , the first-stage PIC structure 202 and the middle-stage PIC structure 203 .

The multi-path searcher group 205 searches to obtain the path-delay information of each user, and sends the path-delay information of all users to the first-level PIC structure 202 , the intermediate-level PIC structure 203 and the last-level PIC structure 204 . As shown in FIG. 2, the baseband signal enters the multipath searcher group 205. Assuming that the system has K users, the multipath searcher group 205 has K multipath searchers. Each user corresponds to a multipath searcher, where K is a positive integer greater than 1.

Processing of the first-level PIC structure

Fig. 3 shows the first stage PIC structure in the uplink dedicated physical channel multi-user receiving device. The first-level PIC structure 202 is composed of K user signal processing units 300 and one interference cancellation unit 320 . Each user corresponds to a user signal processing unit 300 . As shown in Figure 3, the baseband signal entering the first-stage PIC structure 202 enters the signal processing unit 300 of each user in parallel, and the multipath delay information of each user entering the first-stage PIC structure 202 enters the signal processing unit of the corresponding user respectively 300. The signal processing unit 300 of each user performs exactly the same function.

The baseband signal entering the user signal processing unit 300 and the multipath delay information of the user enter the DPDCH processing channel and the DPCCH processing channel respectively.

The DPCCH despreading unit 302 performs multipath despreading on the input baseband signal according to the spreading code of the DPCCH channel, that is, the product of the DPCCH channel code and the scrambling code, and the input multipath delay information, and sends the multipath despreading result to RAKE combining unit 307 for channel estimation unit 304, power control unit 303, noise power estimation unit 308 and DPCCH channel.

The channel estimation unit 304 obtains the channel estimation of each path from the despreading results of each path of the DPCCH, and sends the channel estimation results to the RAKE combination unit 305 of the DPDCH channel and the RAKE combination unit 307 of the DPCCH channel at the same time.

The power control unit 303 obtains a power control command from the despreading results of each path of the input DPCCH channel, and feeds back the power control command as an output of the first-stage PIC to the transmitting end of the user.

The noise power estimation unit 308 obtains the estimation of the noise power of the DPCCH channel from the despreading results of each path of the DPCCH, and simultaneously sends the estimation result of the noise power to the DPDCH soft decision and soft decision weighting unit 309 and the DPCCH soft decision and soft decision weighting unit 310.

The RAKE combination unit 307 of the DPCCH channel is used to combine the input channel estimation results to perform de-channel modulation and RAKE combination on the input DPCCH despreading results, and send the combination results to the DPCCH soft decision and soft decision weighting unit 310 and TFCI interpreter respectively. Code unit 306.

The TFCI decoding unit 306 is configured to perform TFCI decoding on the input RAKE combination result of the DPCCH channel to obtain the spreading factor of the DPDCH channel, and send the spreading factor to the DPDCH despreading unit 301 .

The DPDCH despreading unit 301 performs multipath despreading on the baseband signal according to the spreading code of the DPDCH channel, that is, the product of the DPDCH channel code and the scrambling code, as well as the input multipath delay information and the spreading factor obtained after TFCI decoding , and send the multipath despreading result to the RAKE combination unit 305 of the DPDCH channel.

The RAKE combination unit 305 of DPDCH is used to perform de-channel modulation and RAKE combination on the DPDCH despreading result in combination with the input channel estimation result, and send the combination result to the DPDCH soft decision and soft decision weighting unit 309 .

The DPDCH soft decision and soft decision weighting unit 309 obtains the soft decision of each DPDCH symbol from the DPDCH RAKE combination result and the noise power estimation result, and then performs soft decision weighting. The DPCCH soft decision and soft decision weighting unit 310 obtains the soft decision of each DPCCH symbol from the DPCCH RAKE combination result and the noise power estimation result, and then performs soft decision weighting. The weight value of the soft decision weight of the DPDCH channel and the weight value of the soft decision weight of the DPCCH channel may take different values. When calculating the soft decision of the DPDCH channel, the noise power of the DPDCH channel must be converted from the estimation of the noise power of the DPCCH channel at first.

The signal regeneration unit 311 obtains the symbol-level regeneration signal and the chip-level regeneration signal of the user from the soft decision result of the DPDCH channel, the soft decision result of the DPCCH channel, and the delay information of each path of the user, and sends the chip-level regeneration signal to the interference pair Cancellation unit 320; the symbol correction subunit of the signal processing unit 400 that sends the symbol-level regenerated signal to the same user in the intermediate stage PIC structure 203.

The chip-level regenerated signals and baseband signals of all users enter the signal summing device 321 in the interference canceling unit 320 . The signal summing device 321 sums the input chip-level reproduction signals of each user, and then sends the summation result to the shaping and matched filtering unit 322 . The shaping and matched filtering unit 322 performs shaping filtering and matching filtering on the input signal. The shaping filter is the same as the shaping filter used in the modulation part of the uplink dedicated physical channel, and the matched filter is the matched filter used in the receiving end of the uplink dedicated physical channel. The filtering result is sent to the residual calculation unit 323 . The baseband signal also enters the residual calculation unit. The residual calculation unit 323 subtracts the filtering result from the baseband signal to obtain a residual signal, and sends the residual signal to the next-level PIC structure as the output signal of the current-level PIC. In the next-level PIC structure, the signal is parallelized Signal processing unit sent to each user.

For the first-level PIC structure, the spreading factor obtained by TFCI decoding can be used only by the current-level PIC structure, or can be transmitted to subsequent levels of PIC structures for use by the DPDCH despreading units in the subsequent PIC structures.

Processing of PIC structures at intermediate levels

The structures of the middle levels of PICs are exactly the same, and the following uses the second level of PIC structures as an example to illustrate the processing process of the middle levels of PIC structures.

Fig. 4 shows the structure of the intermediate stage PIC in the uplink dedicated physical channel multi-user receiving device. The residual signal obtained by the first-stage PIC structure 202 , the symbol-level regenerated signal of each user, and the path delay information of each user enter the intermediate-stage PIC structure 203 . The intermediate PIC structure 203 is still composed of K user signal processing units 400 and an interference cancellation unit 420 . There is one user signal processing unit 400 for each user. The user signal processing unit 400 of each user performs exactly the same function.

As shown in FIG. 4 , in the intermediate stage PIC structure 203 , the input signals of the user's signal processing unit 400 are: the residual signal, the symbol-level regenerated signal of the user, and the path delay information of the user.

The user's signal processing unit 400 first sends the user's multipath delay information and residual signal to the DPDCH channel processing channel and the DPCCH channel processing channel at the same time.

The DPDCH despreading unit 401 performs multipath despreading on the input residual signal according to the spreading code of the DPDCH channel, that is, the product of the DPDCH channel code and the scrambling code, and the input multipath delay information and the spreading factor of the DPDCH channel, And the despreading result is sent to the symbol correction unit 405 of the DPDCH channel; the DPCCH despreading unit 402 is based on the product of the spreading code of the DPCCH channel, that is, the DPCCH channel code and the scrambling code, and the input multipath time delay information, to the input residual The difference signal is subjected to multipath despreading, and the despreading result is sent to the channel estimation unit 403, the noise power estimation unit 404, and the symbol correction unit 406 of the DPCCH channel.

The channel estimation unit 403 obtains the channel estimation of each path from the despreading results of each path of the DPCCH, and sends the channel estimation results to the RAKE combination unit 407 of the DPDCH channel and the RAKE combination unit 408 of the DPCCH channel at the same time.

The noise power estimation unit 404 obtains the noise power estimation of the DPCCH channel from the input despreading results of each path of the DPCCH channel, and sends the noise power estimation results to the following two soft decision and soft decision weighting units at the same time.

The symbol correction unit 405 of the DPDCH channel performs symbol-level correction on the input despreading result of the DPDCH channel, that is, adds the despreading result of a certain path of the DPDCH channel to the symbol-level regenerated signal of the path. The symbol correction unit 406 of the DPCCH channel performs symbol-level correction on the input despreading result of the DPCCH channel, that is, adding the despreading result of a certain path of the DPCCH channel to the symbol-level regenerated signal of the path.

The RAKE combining unit 407 of the DPDCH channel and the RAKE combining unit 408 of the DPCCH channel perform de-channel modulation and multipath combining on the DPDCH symbol correction result and the DPCCH symbol correction result respectively, and send the combination result to the DPDCH soft decision and soft decision weighting respectively Unit 409 and DPCCH soft decision and soft decision weighting unit 410 .

The DPDCH soft decision and soft decision weighting unit 409 obtains the soft decision of each symbol of the DPDCH by the RAKE combination result of the input signal, that is, the DPDCH channel, and the estimation result of the noise power, and then performs soft decision weighting; the DPCCH soft decision and soft decision weighting unit 410 is composed of The input signal is the RAKE combination result of the DPCCH channel and the estimation result of the noise power to obtain the soft decision of each symbol of the DPCCH, and then perform soft decision weighting. The weight value of the soft decision weight of the DPDCH channel and the weight value of the soft decision weight of the DPCCH channel may take different values. However, the weight value of the soft decision weight of the DPDCH at this level is greater than the weight value of the soft decision weight of the previous level. The same is true for the weight of the soft decision weight of the DPCCH channel.

The signal regeneration unit 411 obtains the symbol-level regeneration signal and the chip-level regeneration signal of the user from the DPDCH channel soft decision result, the DPCCH channel soft-decision result and the user's delay information of each path, and sends the chip-level regeneration signal to the interference pair Cancellation unit 420; the symbol correction subunit that sends the symbol-level regenerated signal to the signal processing unit of the same user in the subsequent PIC structure 204.

The chip-level regenerated signals and baseband signals of all users enter the signal summing device 421 in the interference canceling unit 420 . The signal summing device 421 sums the input chip-level reproduction signals of each user, and then sends the summation result to the shaping and matched filtering unit 422 . The shaping and matched filtering unit 422 performs shaping filtering and matching filtering on the input signal. The filtering result is sent to the residual calculation unit 423 . The baseband signal also enters the residual calculation unit. The residual calculation unit 423 subtracts the filtering result from the baseband signal to obtain the residual signal, and sends the residual signal as the output signal of the PIC of the current stage to the next-stage PIC structure. In the next-stage PIC structure, the signal is parallelized Signal processing unit sent to each user.

The DPDCH despreading unit needs to know the spreading factor of the DPDCH. The spreading factor can be obtained by decoding the TFCI in the first-stage PIC structure, or can be obtained by the spreading factor calculation unit of the current-stage PIC. The spreading factor calculation unit 430 of the PIC at this stage includes a TFCI decoder 431, which performs TFCI decoding on the RAKE combination result of the DPCCH channel to obtain the spreading factor of the DPDCH channel. After the interference cancellation of the previous PIC structure, the SNR of the RAKE combination result of the DPCCH channel in the current PIC structure should be higher than the SNR of the RAKE combination result of the DPCCH channel in the previous PIC structure. Therefore, the current level The bit error rate of the spreading factor obtained by TFCI decoding will be smaller. Therefore, using the spreading factor calculation unit 430 at this stage, and using the spreading factor obtained by this unit to perform DPDCH despreading will be more beneficial to user detection. However, TFCI decoding not only increases complexity, but also increases time delay. Whether to use a spreading factor calculation unit at this stage can be determined according to needs.

Subsequent intermediate-level PIC structures perform the same operations.

Processing of the last level PIC structure

Fig. 5 shows the last stage PIC structure in the uplink dedicated physical channel multi-user receiving device. The last-level PIC structure 204 is composed of K user signal processing units 500 . The signal processing unit 500 of the user is shown in FIG. 5 .

The input of the signal processing unit 500 is the residual signal obtained in the previous stage, the symbol-level regenerated signal, and the multipath delay information. The user signal processing unit 500 first sends the multipath delay information and the residual signal to the DPDCH processing channel and the DPCCH processing channel respectively.

The DPDCH despreading unit 501 performs multipath despreading on the input residual signal according to the spreading code of the DPDCH channel, that is, the product of the DPDCH channel code and the scrambling code, and the input multipath delay information and the spreading factor of the DPDCH channel, And the despreading result is sent to the symbol modification unit 504 of the DPDCH channel; the DPCCH despreading unit 502 is based on the product of the spreading code of the DPCCH channel, that is, the DPCCH channel code and the scrambling code, and the input multipath time delay information, to the input residual The difference signal is subjected to multipath despreading, and the despreading result is sent to the channel estimation unit 503 and the symbol correction unit 505 of the DPCCH channel.

The channel estimation unit 503 obtains the channel estimation of each path from the despreading results of each path of the DPCCH, and sends the channel estimation results to the RAKE combining unit 506 of the DPDCH channel and the RAKE combining unit 507 of the DPCCH channel at the same time.

The symbol correction unit 504 of the DPDCH channel performs symbol-level correction on the input despreading result of the DPDCH channel, that is, adds the despreading result of a certain path of the DPDCH channel to the symbol-level regenerated signal of the path. The symbol correction unit 505 of the DPCCH channel performs symbol-level correction on the input despreading result of the DPCCH channel, that is, adds the despreading result of a certain path of the DPCCH channel to the symbol-level regenerated signal of the path.

The RAKE merging unit 506 of the DPDCH channel and the RAKE merging unit 507 of the DPCCH channel perform de-channel modulation and multipath combining on the DPDCH symbol correction result and the DPCCH symbol correction result respectively in combination with the channel estimation result. The combined result of the DPDCH channel is sent to the channel decoder 508 of the DPDCH channel, and the combined result of the DPCCH channel is sent to the hard decision unit 509 of the DPCCH channel.

The channel decoder 508 performs channel decoding on the input signal to obtain information bits sent by the DPDCH channel. For the 12.2 kbps uplink dedicated physical channel, the channel decoding process is the reverse process of the process shown in Figure 8 .

The hard decision unit 509 performs hard decision on the input signal to obtain the information bits sent by the DPCCH channel.

The despreading unit 501 of the DPDCH needs to know the spreading factor of the DPDCH. The spreading factor can be obtained by decoding the TFCI in the previous stage of the PIC structure, or can be obtained by the spreading factor calculation unit 510 of the current stage of the PIC. Whether to use a spreading factor calculation unit at this stage can be determined according to needs.

The number of stages of the PIC structure can be determined as required. It is possible to use only the first-level and last-level PIC structures, or more levels of PIC structures.

Claims (5)

1. be used for the channel coding method that the multi-user receives in a Wideband Code Division Multiple Access (WCDMA) (WCDMA) system, it is characterized in that described channel coding method may further comprise the steps:

A, Dedicated Traffic Channel (DTCH) signal and Dedicated Control Channel (DCCH) signal are carried out the Cyclic Redundancy Check bit respectively add;

B, the Dedicated Traffic Channel signal after cyclic redundancy check bits added and Dedicated Control Channel signal carry out the tail bit respectively and add;

C, Dedicated Traffic Channel signal and Dedicated Control Channel signal after the tail bit added carry out 1/2 speed convolutional encoding respectively;

D, Dedicated Traffic Channel signal after the 1/2 speed convolutional encoding and Dedicated Control Channel signal are carried out respectively interweaving the first time;

E, Dedicated Traffic Channel signal and Dedicated Control Channel signal after interweaving are for the first time carried out wireless frame segmentation respectively;

F, Dedicated Traffic Channel signal after the wireless frame segmentation and Dedicated Control Channel signal are carried out rate-matched respectively;

G, the Dedicated Traffic Channel signal after the rate-matched and the data multiplex of Dedicated Control Channel signal are in the same place, carry out that interweave with the second time and time slot dividing, form Dedicated Physical Data Channel (DPDCH) signal.

2. channel coding method as claimed in claim 1, it is further characterized in that described 1/2 speed convolutional encoding is according to the predetermined operation in 25.212 agreements of 3GPP.

3. channel coding method as claimed in claim 1, it is further characterized in that, the described first time of time friendship, wireless frame segmentation, rate-matched, data multiplex, for the second time interweave and time slot dividing all according to the predetermined operation in 25.212 agreements of 3GPP.

4. as claim 1 or 3 described channel coding methods, it is further characterized in that the speed matching method in 25.212 agreements of described rate-matched employing 3GPP specifically adopts even hole knockout.

5. channel coding method as claimed in claim 1, it is further characterized in that the spreading factor of described DPDCH channel signal is 128.

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