JP2005323003A - Transmission apparatus and reception apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enhance a transmission efficiency furthermore by avoiding a reception error by an SCH and controlling the avoidance of the reception error in response to a change in the effect of the SCH. <P>SOLUTION: A transmission apparatus for transmitting transmission data to a reception apparatus through code division is characterized by including a synchronizing signal transmission means for transmitting a synchronizing signal in a burst form, and a control means for controlling a transmission timing so as not to transmit the transmission data except a transmission period of the synchronizing signal. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a transmission device and a reception device, for example, a radio base station and a mobile station in a mobile radio communication system employing a W-CDMA communication system.

  Currently, standardization of the W-CDMA system, which is one system of the third generation mobile communication system, is being promoted by 3GPP (3rd Generation Partnership Project). As one of the themes of standardization, HSDPA (High Speed Downlink Packet Access) that provides a maximum transmission speed of about 14 Mbps in the downlink is defined.

  HSDPA employs an adaptive coded modulation system, and is characterized by, for example, adaptively switching between a QPSK modulation system and a 16-value QAM system according to the radio environment between a base station and a mobile station.

  HSDPA adopts an H-ARQ (Hybrid Automatic Repeat reQuest) system. In HSDPA, when the mobile station detects an error in the received data from the base station, data is retransmitted from the base station in response to a request from the mobile station, and the mobile station is retransmitted with already received data. It is characterized by performing error correction decoding using both received data. As described above, in H-ARQ, even if there is an error, the already received data is effectively used to increase the error correction decoding gain and to reduce the number of retransmissions.

  Main radio channels used for HSDPA include HS-SCCH (High Speed-Shared Control Channel), HS-PDSCH (High Speed-Physical Downlink Shared Channel), and HS-DPCCH (High Speed-Dedicated Physical Control Channel).

  HS-SCCH and HS-PDSCH are both common channels in the downlink direction (that is, the direction from the base station to the mobile station), and HS-SCCH transmits various parameters related to data to be transmitted on HS-PDSCH. Control channel. The various parameters include, for example, modulation type information indicating which modulation method is used to transmit data by HS-PDSCH, the number of assigned spreading codes (number of codes), a pattern of rate matching performed on transmission data, etc. Information.

  On the other hand, the HS-DPCCH is an individual control channel in the uplink direction (that is, the direction from the mobile station to the base station), and an ACK signal can be received depending on whether or not data received via the HS-PDSCH is receivable. This is used when the mobile station transmits a NACK signal to the base station. When the mobile station fails to receive data (when the received data is a CRC error, etc.), the base station executes retransmission control because a NACK signal is transmitted from the mobile station.

In addition, the HS-DPCCH is also used by a mobile station that measures the reception quality (for example, SIR) of a received signal from a base station and transmits the result as a CQI (Channel Quality Indicator) to the base station. Based on the received CQI, the base station determines whether the downlink radio environment is good or not. If it is good, the base station switches to a modulation method capable of transmitting data at a higher speed. Switch to the modulation method to be transmitted (that is, perform adaptive modulation).
・ "Channel structure"
Next, a channel configuration in HSDPA will be described.

  FIG. 1 is a diagram for illustrating a channel configuration in HSDPA. Since W-CDMA employs a code division multiplexing system, each channel is separated by a code.

  First, the channels not described will be briefly described.

  CPICH (Common Pilot Channel) and SCH (Synchronization Channel) are downlink common channels, respectively.

  The CPICH is a channel used for channel estimation, cell search, and a timing reference for other downlink physical channels in the same cell in a mobile station, and is a channel for transmitting a so-called pilot signal. Strictly speaking, the SCH includes a P-SCH (Primary SCH) and an S-SCH (Secondary SCH), and is a channel transmitted in bursts at the first 256 chips of each slot. Note that the SCH is received by the mobile station in a three-stage cell search and used to establish slot synchronization and frame synchronization.

  Next, channel timing relationships will be described with reference to FIG.

  As shown in the figure, each channel constitutes one frame (10 ms) with 15 slots (each slot corresponds to a length of 2560 chips). As described above, since CPICH is used as a reference for other channels, the head of the SCH and HS-SCCH frames coincides with the head of the CPICH frame. Here, the head of the HS-PDSCH frame is delayed by 2 slots with respect to HS-SCCH or the like. However, after the mobile station receives the modulation type information via HS-SCCH, the received modulation type is changed to the received modulation type. This is because HS-PDSCH can be demodulated by a corresponding demodulation method. HS-SCCH and HS-PDSCH constitute one subframe with three slots.

  This is because HS-DPCCH is not synchronized with CPICH, but is an uplink channel and is based on timing generated in the mobile station. Since one subframe corresponds to a length of 3 × 2560 chips, when the spreading factor (SF) is 16 and transmission is performed with 16-value QAM, transmission of 1920 bits is performed with one spreading code per subframe. Can be performed.

The above is a simple description of the channel configuration of HSDPA. Next, a process until transmission data is transmitted via HS-PDSCH will be described with reference to a block diagram.
・ Base station configuration
FIG. 2 shows the configuration of a base station that supports HSDPA.

  In the figure, 1 is a CRC adding unit, 2 is a code block dividing unit, 3 is a channel coding unit, 4 is a bit separating unit, 5 is a rate matching unit, 6 is a bit collecting unit, and 7 is a modulating unit.

  Next, the operation of each block will be described. In order to facilitate understanding, as an example, the number of bits after each processing is set such that the transmission data (TBS: transport block size) is 27952 bits and the data amount (process memory size) after the first rate matching is 28800 bits. Describe changes in The process memory size is a data size that can be set according to the processing capability of the mobile station that is the receiving apparatus.

  The 27952 bits of transmission data transmitted via the HS-PDSCH (data stored in one subframe of the HS-PDSCH in FIG. 1) are first subjected to CRC calculation processing in one CRC adding unit. Some 24 bits are added to the end of the transmission data. Then, 27976 bits of the transmission data to which the CRC calculation result is added are input to the code block dividing unit 2, to which 2 bit filler bits are added, and divided into 6 blocks of 4663 bits. This is for shortening the data length of the unit for performing error correction coding in consideration of the decoding processing load on the receiving side. When the data length exceeds a predetermined length, it is equally divided into a plurality of blocks. Note that the number of divisions may be other than 6, and division is not necessary when the data length is short.

  Each of the divided transmission data is handled as data to be subjected to separate error correction coding in the channel coding unit 3. That is, error correction coding processing is performed on each of the divided first block, second block,. An example of channel coding is turbo coding. In the turbo encoding, first, 4 bits of tail bits are added to each of 4663 bits, and encoding is performed at an encoding rate of 1/3. Therefore, the total encoded data of (4663 + 4) × 3 × 6 = 84006 bits Is output.

  Here, the turbo coding will be briefly described. In turbo coding, if the data to be coded is U, based on U, U itself, U ′ obtained by convolutional coding of U, and U are interleaved (rearrangement processing). Similarly, U ″ obtained by convolutional coding is output. Here, U is referred to as a systematic bit, and is data used in both of the two element decoders in turbo decoding. Since U is frequently used, it can be understood that U is highly important data. On the other hand, U ′ and U ″ are redundant bits, each of which is data used by one of the two element decoders. Since the usage frequency is low, it can be understood that the importance is lower than U.

  That is, the systematic bits are more important than the redundant bits, and it can be said that a correct decoding result can be obtained by the turbo decoder when the systematic bits are received more correctly.

  The systematic bits and the redundant bits generated in this way are input to the bit separation unit 4 as serial data, and the bit separation unit 4 converts the input serial data into U, U ′, U ″. The data is separated into three systems and output as parallel data.

  The rate matching unit 5 performs a puncturing process for deleting bits by a predetermined algorithm or a repetition process by repeating the bits so as to be within a subframe composed of 3 slots of HS-PDSCH. Here, the input 84006 bits are compressed to 28800 bits by puncturing and output.

  In this way, the bits subjected to the bit adaptation processing for the subframe in the rate matching unit 5 are input in parallel to the bit collection unit 6.

  For example, the bit collection unit 6 generates and outputs a 4-bit bit string indicating each signal point of 16-level QAM modulation based on the input data. When generating a bit string, systematic bits are preferentially arranged on the higher-order bit side that is not prone to error during the first transmission.

  Modulator 7 sorts the 28,800 bits that are input to each of the 15 spreading codes, spreads the 960-bit data for I and Q at SF = 16, and synthesizes the signal after spreading processing Then, 16-value QAM modulation is performed, and further, converted into a radio frequency by frequency conversion, and then transmitted to an antenna not shown.

The matter regarding HSDPA mentioned above is disclosed by the following patent document 1 nonpatent literature 1, for example.
3G TS 25.212 (3rd Generation Partnership Project: Technical Specification Group Radio Access Network; Multiplexing and channel coding (FDD))

  According to the background art described above, the transmission time overlaps the SCH at the beginning of each slot of the HS-PDSCH. Specifically, since the SCH occupies 256 chips from the head of each slot, it occupies 1/10 time of one slot. On the other hand, since HS-PDSCH has a length of 3 × 2560 chips per subframe, when SF = 16, 3 × 2560/10/16 = 48 bits are transmitted simultaneously with the SCH.

  However, the SCH is a burst-like channel that is not orthogonal to other channels that are spread code multiplexed in order to achieve high-speed slot and frame synchronization establishment by the mobile station.

  In addition, since the SCH is commonly used by all mobile stations in the cell and is necessary at the earliest stage of communication establishment called cell search, the SCH is transmitted to other channels with relatively large power.

  Therefore, for HS-PDSCH that performs data transmission at high speed using a modulation method with a small spreading factor and a narrow symbol point interval with respect to average power, such as 16-value QAM, interference by SCH has a significant effect. , Will cause a reception error. Further, when a reception error occurs, retransmission control by H-ARQ is repeated, so that its own transmission efficiency is lowered and further transmission of other HSDPA users is harmed.

  Accordingly, one of the objects of the present invention is to avoid reception errors due to SCH.

  It is another object of the present invention to further improve transmission efficiency by controlling avoidance of reception errors in accordance with changes in the influence of SCH.

  It is to be noted that the present invention is not limited to the above-described object, and is an effect derived from each configuration shown in the best mode for carrying out the invention described later, and has an effect that cannot be obtained by the conventional technique. Can be positioned as one.

(1) According to the present invention, in a transmission apparatus that transmits transmission data to a reception apparatus by code division, the synchronization signal transmission unit that transmits a synchronization signal in a burst form and the transmission period of the synchronization signal are excluded. And a control unit that controls transmission timing so as to transmit transmission data.
(2) In the transmission according to (1), the transmission device may further include a bit addition unit so as to transmit an additional bit during the transmission period of the synchronization signal. Use the device.
(3) Further, in the present invention, the transmission device according to (2) is used, wherein the additional bit is a copy or dummy bit of a part of the transmission data.
(4) Further, in the present invention, the control means, based on a received signal from the receiving apparatus, transmits the transmission data excluding the transmission period of the synchronization signal, and the synchronization signal The transmission device according to (1), wherein the transmission data transmission mode including the transmission period can be switched.
(5) Further, in the present invention, the synchronization signal transmitted in bursts and the receiving device that receives the signal from the transmitting device that transmits the transmission data transmitted by code division exclude the transmission period of the synchronizing signal. A receiving apparatus comprising: a receiving means for receiving transmitted transmission data; and a demodulating / decoding means for performing demodulation and decoding processing based on the received transmission data.
(6) Further, in the present invention, the demodulation or decoding means performs demodulation or decoding by deleting the additional bits transmitted during the transmission period of the synchronization signal from the received signal (5). The described receiving apparatus is used.
(7) In the present invention, the demodulation or decoding means combines the additional bits transmitted from the received signal during the transmission period of the synchronization signal into the transmission data transmitted excluding the transmission period of the synchronization signal. The receiving apparatus according to (5) is used, which performs demodulation or decoding based on the received signal obtained in this way.
(8) Further, according to the present invention, a mode in which the transmission apparatus transmits the transmission data excluding the transmission period of the synchronization signal and a transmission period of the synchronization signal are also determined according to a reception situation. And a feedback means for transmitting a signal for instructing switching to a mode for transmitting the transmission data.

  According to the transmission apparatus of the present invention, transmission data can be transmitted and received in a period excluding the transmission period of the synchronization signal that is transmitted in bursts, so that the influence of the synchronization signal can be avoided.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[A] Description of First Embodiment FIG. 3 is a diagram illustrating a transmission apparatus according to the present invention.

  As an example of the transmission apparatus, a transmission apparatus (radio base station) of the W-CDMA communication system corresponding to the HSDPA described above will be described. It is also possible to apply to a transmission device in another communication system.

  In the figure, reference numeral 10 denotes a control unit that sequentially outputs transmission data (transport block to be transmitted in one subframe) transmitted via the HS-PDSCH and controls each unit (11 to 26, etc.). Since HS-PDSCH is a common channel, transmission data that are sequentially output are allowed to be addressed to different mobile stations.

  Here, as the transmission data, in order to reduce the transmission data by at least the number of bits corresponding to the transmission period of the SCH, the transmission data is multiplied by 0.9 with respect to the above-mentioned transport block size of 27952 bits, and the decimal part is It is output as 25156-bit data, which is the number of bits discarded. In this way, reducing the predetermined number of transport blocks before encoding to a small number of bits is called transport block compression. According to this, it is possible to suppress the compression rate for the encoded data from becoming substantially high by reducing the transport block size itself from the beginning.

  Of course, the transport block size is made the same as before (the transport block is uncompressed), and the encoded data after channel coding is compressed by the first rate matching unit 16, the second rate matching unit 18, etc., which will be described later. The bits corresponding to the SCH transmission period may be deleted. It should be noted that making the number of bits after encoding smaller than the number of bits that can be stored in one entire sub-frame of HS-PDSCH is called compression of encoded data.

The main control of the control unit 10 includes the following items.
(1) Retransmission is controlled based on a NACK signal received by the receiving unit 26 described later.
(2) Control is performed so that transmission data is not arranged in bits within the transmission period of the SCH.

  11 is a CRC attachment that performs CRC calculation on sequentially input transmission data (data to be transmitted in the same radio frame) and adds 24 bits as a CRC calculation result to the end of the transmission data. Reference numeral 12 denotes a bit scrambling section that gives transmission data randomness by scrambling transmission data to which the CRC calculation result is added in units of bits. Note that after adding the CRC calculation result, it becomes 25180 bits.

13 is a bit input for the purpose of preventing an increase in the amount of calculation of the decoder on the receiving side due to the data length to be encoded becoming too long in the next channel encoding. A code block segmentation unit that divides (for example, bisects) when scrambled transmission data exceeds a predetermined data length. In the figure, the input data length exceeds the predetermined data length.
The filler bit is 0, and 25180 ÷ 5 = 5036 bits are divided.

  Reference numeral 14 denotes a channel coding unit that performs error correction coding processing on each divided data separately. Here, assuming that the tail bits are 4 bits and the coding rate is 1/3, the total number of bits after coding is (5036 + 4) × 3 × 5 = 75600 bits.

  Note that the above-described turbo encoder is preferably used as the channel encoding unit 14, and a turbo encoder is also used here.

  Therefore, as described above, the first output is obtained by convolutionally encoding the systematic bits (U) and the systematic bits (U), which are the same data as the data to be encoded, for the first block. The obtained first redundant bit (U ′) and the second redundant bit (U ″) obtained by interleaving the systematic bit and then performing convolutional coding in the same manner are included. Similarly, the second output includes a systematic bit (U), a first redundant bit (U ′), and a second redundant bit (U ″) for the second block.

  15 separates each systematic bit (U), first redundant bit (U ′), and second redundant bit (U ″) of each block serially input from the channel encoder 14 (turbo encoder). The bit separation part to be output is shown.

16 is such that the input data (if divided into a plurality of blocks, all of the data of the divided blocks) has a data amount that fits in the process memory size determined according to the capability of the mobile station. a first rate matching (1 ^st rate matching) unit for performing rate matching processing such as puncturing process (decimation by deleting bits) for the input data.

  Conventionally, the process memory size, which is the data size after rate matching processing, is 28800 bits. However, in this embodiment, in order to avoid transmission of transmission data at the same time as SCH, the number of bits is compressed compared to the conventional case. . That is, the rate matching process is performed so that 25920 bits, which is 0.9 times the number of 2800 bits, are obtained.

  When the transport block size is the same as the conventional one (when the transport block is not compressed), the data input to the first rate matching unit is 84006 bits as in the conventional case. In order to avoid simultaneous transmission, the number of bits after rate matching processing in the first rate matching unit 16 is set to 25920 bits, which is 0.9 times the process memory size, and further, rate matching in the second rate matching unit 18 to be described later The rate matching process may be performed so that the processed bits become 25920 bits, which is 0.9 times the number of bits that can be stored in one subframe of HS-PDSCH.

  Here, in the first rate matching unit 16, the process memory size remains 28800 bits, and the second rate matching unit 18 can compress the number of bits to 25920 bits.

  Reference numeral 17 denotes a virtual buffer section. At the time of retransmission, by outputting the stored data, the processing from the CRC adding unit 11 to the first rate matching unit 16 can be omitted. However, if the coding rate is to be changed at the time of retransmission, the stored data is stored. It is desirable to output the transmission data stored in the control unit 10 again without using the processed data. Note that a buffer is not provided as the virtual buffer unit 17, and it can be made through as it is. In this case, the retransmission data is output again from the control unit 10.

18, the control unit 10, shows a second rate matching (2 ^nd rate matching) unit for adjusting the data length that can be accommodated in one subframe specified, puncturing (thinning), repetition processing (repetition ) To adjust the data length of the input data so that the specified data length is obtained.

  Here, in order to avoid overlapping with the SCH, the data length that can be stored in one subframe has to be shorter than the conventional one. Specifically, since the number of bits that can be stored in one subframe (spreading code: 15, 16-value QAM modulation scheme, SF = 16) is 28800, in order to avoid overlap with SCH Needs to be 0.920 times 25920 bits.

  In this embodiment, the number of bits that can be stored in one subframe that avoids SCH and the process memory size match, and in fact, the second rate matching processing is output without being specially processed. Become.

  Of course, if the number of bits that can be stored in one subframe that avoids SCH is smaller than the process memory size, the number of bits that can be stored in one subframe that avoids SCH by the puncturing process in the second rate matching unit 18 Bit deletion is performed as follows.

  Reference numeral 19 denotes a bit collection unit that arranges data from the second rate matching unit 19 in a plurality of bit strings. That is, by arranging by a predetermined bit arrangement method, a plurality of bit strings for indicating signal points on the phase plane are output. In this embodiment, since the 16-value QAM modulation method is used, the bit string is composed of 4 bits. However, when the 64-value QAM modulation method is used, the bit string is 6 bits, and when the QPSK modulation method is used, the bit string is 2 bits. Make a bit.

  Reference numeral 20 denotes a physical channel division / bit addition unit that divides and outputs a bit string to the same number of systems as the number of spreading codes (number of codes) notified by the control unit 10 and adds bits. That is, when the number of codes in the transmission parameter notified by the control unit 10 is 15 (N), the input bit string is sequentially allocated to the systems 1 to 15 (N), and the data of each distributed system is I, Q data 288 (= 25920 ÷ 15 ÷ 2 ÷ 3) bits obtained by dividing into three (because one frame contains three slots and the top of each slot overlaps with the SCH). Add 32 bits. Here, 32 bits are additional bits, and a part of the transmission data can be used, or a predetermined bit (so-called dummy bit) can be used.

  In addition, 32 bits are added to the head of each divided bit so that the timing at which the 32-bit portion is transmitted and the timing at which the SCH is transmitted overlap.

  Reference numeral 21 denotes an interleaving unit that performs interleaving processing on each of the N bit strings and outputs the result.

  Reference numeral 22 denotes a constellation re-arrangement for 16 QAM unit that can re-arrange bits in each bit string for each input bit string. For example, at the time of the first transmission, each input bit string can be output as it is, and the bits can be rearranged at the time of retransmission in H-ARQ described above. The bit rearrangement is, for example, processing such as switching the upper bit and the lower bit, and it is preferable to perform bit replacement according to the same rule for a plurality of bit strings. In addition, it is possible to pass through as it is at the time of retransmission. Reference numeral 23 denotes a physical channel mapping unit that distributes the N-system bit string in the subsequent stage to the corresponding spreading unit of the spreading processing unit 24 in the subsequent stage.

  24 includes a plurality of spreading sections, each of which outputs a corresponding I and Q voltage value based on each of N systems of bit strings, and performs a spreading process using different spreading codes, and outputs a spreading process (Spreading) section. Show.

  25 synthesizes each signal spread by the spread processing unit 24, performs amplitude phase modulation such as a 16-value QAM modulation system based on this, amplifies it by a variable gain amplifier, and further converts the frequency into a radio signal Then, a modulation unit that enables output to the antenna side and transmission as a radio signal is shown.

  In addition, additional bits are inserted at the head of each slot of the HS-PDSCH and transmitted simultaneously with the SCH. Transmission data itself subjected to a series of processing from 10 to 25 avoids simultaneous transmission with the SCH. .

  FIG. 4 is a diagram for explaining this timing relationship.

  In the figure, in the time zone indicated by hatching in HS-PDSCH (time zone overlapping with the time zone where SCH transmission is performed), transmission of the additional bits described above is performed, and the transmission data is indicated by the hatched portion in the subframe. Transmission is performed at a time excluding the time zone.

  Reference numeral 26 denotes a reception unit, which receives a signal from a mobile station received via HS-DPCCH or the like, and gives an ACK, NACK signal, CQI, or the like to the control unit 10.

  As described above, since the HS-PDSCH is transmitted while avoiding the transmission period of the SCH, it is possible to suppress the influence of interference due to the SCH. It should be noted that bits exceeding the number of bits overlapping with the SCH cannot be transmitted within one subframe, but the occurrence rate of retransmission control is suppressed.

  It is desirable to allow only the transmission of additional bits in all time periods in which SCH transmission is performed. However, even if a part of the time period in which SCH transmission is performed, additional bits are transmitted. By transmitting the transmission data, it is possible to obtain an effect that it is possible to suppress the occurrence rate of reception errors in the mobile station and to lower the retransmission probability as compared with the conventional case.

  Next, the receiving apparatus according to the present invention will be described.

  As an example of the receiving apparatus, a receiving apparatus (mobile station) of the W-CDMA communication system corresponding to the HSDPA described above will be described. It is also possible to apply to a receiving device in another communication system.

  In the figure, 31 is a demodulator that performs reception processing such as despreading, 32 is a channel decoder that performs channel decoding (for example, turbo decoding) based on the demodulated received signal, and 33 is a CRC that performs CRC check. A check unit 34 is a control unit, and 35 is a transmission processing unit.

  Briefly describing the operation, the mobile station monitors the HS-SCCH to check whether transmission data is transmitted to the local station via the HS-PDSCH.

  When receiving HS-SCCH and recognizing that there is transmission of HS-PDSCH addressed to its own station, demodulation section 31 performs HS-PDSCH reception processing.

  At this time, since information such as the modulation type and the number of spreading codes is acquired via the HS-SCCH, the control unit 34 sets the demodulation unit 31 to the corresponding detection method and the number of spreading codes according to these parameters. To do.

  Then, the demodulated signal is given to the channel decoding unit 32, and the channel decoding unit 32 performs a decoding process such as turbo decoding.

  It should be noted here that additional bits are inserted in order to avoid SCH during transmission.

  When the additional bit is a dummy bit, the control unit 34 deletes the dummy bit portion by controlling the demodulation unit or the channel decoding unit. At this time, since the number of dummy bits is known as the number of bits overlapping the SCH transmission timing, the additional bits can be easily deleted by deleting the number of known bits from the beginning of the slot. . As a result, the deletion of the dummy bits may be performed at any location so as to exclude the dummy bits from the data to be decoded when performing channel decoding.

  On the other hand, when the additional bit is a copy of a part of the transmission data, the control unit 34 may delete the additional bit part by controlling the demodulation unit or the channel decoding unit. Preferably, the following processing is performed. That is, by combining the transmission data excluding the additional bits and the corresponding additional bit portion, the probability of the bits is increased.

  The channel decoding unit 32 performs decoding based on the combined data. As an example of synthesis, it is conceivable to synthesize likelihood by weighting. The weighting ratio is preferably such that the additional bit portion is weighted below the other bit portions. This is because there is a decrease in certainty because there is interference with the SCH.

  The data decoded by the channel decoding unit 32 is CRC checked by the CRC checking unit 33 and the result is given to the control unit 34.

  The control unit 34 transmits NACK and ACK to the base station via the transmission processing unit 35 depending on whether there is a CRC error.

  Separately, in order to realize adaptive modulation in the base station, the control unit 34 generates a CQI bit based on the SIR of the received signal from the base station and transmits the CQI bit via the transmission processing unit 35.

  The CQI bit will be described in detail in the second embodiment.

  As described above, the mobile station performs the decoding process using bits without SCH interference as a channel decoding target, so that the probability of a reception error is reduced. In addition, since the bit portion subjected to SCH interference is weighted and combined with other transmission data before being decoded, the probability of receiving errors is reduced.

[B] Description of Second Embodiment In the first embodiment, the transport block itself is made smaller (transport block compression), and further after the rate matching processing of the first and second rate matching units 16 and 18. An example in which interference with the SCH is avoided by reducing the number of bits (encoded data compression) (Example 1), and the transport block itself is not reduced (uncompressed transport block), and the first rate matching An example (example 2) is shown in which interference with the SCH is avoided by reducing the number of bits after rate matching processing of the unit 16 and the second rate matching unit 18 (compression of encoded data).

  However, Example 1 is particularly effective when the transmission rate is relatively high and an error correction gain cannot be expected (large CQI), and in Example 2, the transmission rate is relatively low and an error correction gain can be expected (CQI small). ), The conventional example has respective advantages that it is effective for a cell having a relatively low SCH power ratio.

  Therefore, in this embodiment, in order to make the best use of this advantage, while synchronizing whether the example 1, the example 2, or the conventional example is applied between the base station and the mobile station based on the signal from the mobile station. The setting will be changed flexibly.

  That is, when the CPICH reception SIR and the like are good, the CQI value transmitted from the mobile station to the base station is large, and the number of spreading codes and the number of transport blocks to be used is large, so that the base station transmits.

  In the present invention, the CQI value is increased or decreased based on the reception quality (reception error, block error rate, etc.) of HS-PDSCH. For example, if the target block error is 1e-1 and the block error is larger than 2e-1, the CQI value is decreased by 1. If the block error is smaller than 5e-2, the CQI value is increased by 1.

  Here, the correspondence between the CQI value and each parameter follows FIG.

  In FIG. 6, CQI is the value of the CQI bit transmitted to the base station, the number of TBS bits is the size of transmission data that the base station outputs during transmission of one subframe, and the number of codes is the number of codes transmitted from the base station to one mobile station. On the other hand, the number of spreading codes and the modulation type used when transmitting HS-PDSCH when transmitting are the types of modulation when performing adaptive modulation, and there is QPSK other than 16-value QAM in the figure. The TBS compression ON indicates that the compression method of Example 1 is executed, the rate matching unit compression ON indicates that the compression method of Example 2 is executed, and the additional bit ON indicates that an additional bit is added. Of course, OFF indicates that each method is not executed.

  To explain with some examples, CQI = n + 17 when the noise in the radio channel is small. However, in a cell with a large SCH power, this CQI is not stable, and the value shifts to a small CQI. Conversely, in a cell with low SCH power, this CQI tends to stabilize.

  In a cell with low noise on the radio line and high SCH power, CQI = n + 16 is stable. In a cell where the influence of SCH is small, the transmission rate is further increased to CQI = n + 17.

  When the noise on the radio channel increases slightly, CQI = n + 15. However, in a cell with a large SCH power, the CQI is not stable and the CQI CQI = n + 14 is followed. In a cell where the influence of SCH is small, CQI = n + 15 is stable.

  In a cell where the noise on the radio line is equivalent to the description of CQI = n + 15 and the SCH power is large, CQI = n + 14 is stabilized. In a cell where the influence of SCH is small, a transition is made to CQI = n + 15 to further increase the transmission rate.

  When the noise on the radio line increases from the description of CQI = n + 14, the cell with large SCH power stabilizes at CQI = 13. In a cell where the influence of SCH is small, CQI shifts to n + 14 in order to further increase the transmission rate.

  The above is a simple explanation, but the CQI table is configured so that the transmission rate increases as the CQI increases.

  In the figure, an example of a part having a considerably high transmission rate is shown, but actually, there is an example in which QPSK modulation is used in a part omitted by.

  Accordingly, in the same way as in this figure, ON / OFF of compression can also be defined for a portion with a lower transmission rate. However, since the SCH interference becomes more significant as the transmission rate is higher, the transmission rate is higher than a predetermined value. It is preferable to define ON / OFF of compression for a portion corresponding to CQI.

It is a figure for showing the channel structure in HSDPA. It is a figure which shows the structure of the base station which supports HSDPA. 1 shows a transmission apparatus (base station) according to the present invention. It is a figure for showing the channel structure in HSDPA concerning the present invention. It is a figure which shows the receiver (mobile station) which concerns on this invention. It is a figure which shows a CQI table.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 CRC addition part 2 Code block division part 3 Channel encoding part 4 Bit separation part 5 Rate matching part 6 Bit collection part 7 Modulation part 10 Control part 11 CRC addition part 12 Bit scrambling part 13 Code division part 14 Channel encoding part 15 Bit separation unit 16 First rate matching unit 17 Virtual buffer unit 18 Second rate matching unit 19 Bit collection unit 20 Physical channel division / bit addition unit 21 Interleave processing unit 22 Constellation rearrangement unit 23 Physical channel mapping unit 24 Spreading processing unit 25 Modulation unit 26 Reception unit 31 Demodulation unit 32 Channel decoding unit 33 CRC check unit 34 Control unit 35 Transmission processing unit

Claims (8)

In a transmission device that transmits transmission data to a reception device by code division,
Synchronization signal transmitting means for transmitting a synchronization signal in bursts;
Control means for controlling the transmission timing so as to transmit the transmission data excluding the transmission period of the synchronization signal;
A transmission device comprising: The transmission device includes a bit addition unit so as to transmit an additional bit during a transmission period of the synchronization signal.
The transmission apparatus according to claim 1. 3. The transmission apparatus according to claim 2, wherein the additional bit is a copy or dummy bit of a part of the transmission data. The control means includes a mode for transmitting the transmission data excluding a transmission period of the synchronization signal based on a reception signal from the reception apparatus, and a transmission data including the transmission period of the synchronization signal. The mode to transmit can be switched
The transmission apparatus according to claim 1. In a receiving apparatus that receives a signal from a transmitting apparatus that transmits transmission data transmitted by code division, a synchronization signal transmitted in a burst form,
Receiving means for receiving transmission data transmitted excluding the transmission period of the synchronization signal;
Demodulation and decoding means for performing demodulation and decoding processing based on the received transmission data;
A receiving apparatus comprising: The demodulation or decoding means performs demodulation or decoding by deleting additional bits transmitted during the transmission period of the synchronization signal from the received signal.
The receiving apparatus according to claim 5. The demodulating or decoding means is based on the received signal obtained by synthesizing the additional bits transmitted from the received signal during the transmission period of the synchronization signal with the transmission data transmitted excluding the transmission period of the synchronization signal. , Demodulate or decode,
The receiving apparatus according to claim 5. Depending on the reception status, the transmission apparatus transmits the transmission data including the transmission data transmission mode excluding the synchronization signal transmission period and the synchronization signal transmission period. Feedback means for transmitting a signal instructing switching between modes;
The receiving apparatus according to claim 5, further comprising:

Images