TWI389471B - Method and apparatus for supporting joint detection in downlink utra tdd - Google Patents

Description

Method and device for supporting downlink joint detection side in time division duplex code division multi-directional proximity communication system

The present invention relates to a communication method and apparatus in a wireless communication system, and more particularly to a time division duplex code division multiple direction proximity (TDD CDMA) (such as time division synchronous code division multi-directional proximity (TD-SCDMA)) communication. A method and apparatus for supporting downlink joint detection in a system.

In the TDD CDMA-based wireless communication system, there are mainly two types of intra-cell interference: one is because different users share the same frequency band at the same time, and different users allocate different codes due to multipath effects. The resulting non-orthogonality results in multiple access interference (MAL: Multiple Access Interference); the other is due to multipath propagation causing inter-symbol interference (ISI: Inter-Symbol Interference) between different paths of the same user.

In order to effectively eliminate multi-access interference and inter-symbol interference, a technique called joint detection (JD) has been introduced in a conventional TDD CDMA communication system. Joint detection technology, by making full use of user signal code, channel fading, signal delay and other information, can not only improve the quality of signal transmission in the cell, expand the system capacity of the TDD wireless communication system, but also can be applied to the low chip rate ( LCR: Low Chip Rate, 1.28 Mb/s, High Chip Rate (HCR: 3.84 Mb/sec) until 3GPP (3rd Generation Partnership Project) is discussing a higher wafer rate (7.68 Mb) / sec) TDD system, therefore, joint detection technology is becoming one of the key technologies of today's TDD CDMA system.

T3G, a co-investor of Datang, Philips and Samsung, In its first generation of 3G mobile products, joint detection technology, such as zero forcing block linear equalizer (ZF-BLE: zero forcing block linear equalizer), minimum mean square error block linear equalizer (MMSE-BLE) : minimum mean square error block linear equalizer), used in the development design of TD-SCDMA mobile phones.

However, the implementation of the ZF-BLE and MMSE-BLE algorithms requires a prerequisite, that is, the code of all user terminals (UE: user equipment) that needs to be active can perform these two joint detection algorithms. . For the base station, this should not be a problem, because the base station is responsible for resource allocation, so it is convenient to know the code of all users; however, for the user terminal, since the user terminal only knows its own code, There is no knowledge of the codes commonly used for other user terminals in the same time slot. Therefore, there is a certain difficulty in achieving a joint detection algorithm in the user terminal.

In order to achieve joint detection in the user terminal, one solution is to add an "active code detection" module to the receiver of the TD-SCDMA mobile phone, so that it can be in a single user terminal. Restore the code information of other user terminals. For this part of the technology, see the article titled "Performance of active codes detection algorithms for the downlink of TD-SCDMA system" by Kang Shao-li et al. Published in IEEE Inter. Symposium on circuit and systems (ISCS), Vol. 1, 2002, pp. 613-616, and by S. Kourist et al., entitled "3GPP-TDD Terminal Requirements (the Technology requirements of the 3GPP-TDD terminal)", published in the IEE 2000 Inter. conf. on 3G Mobile communication technologies, pages 89-93. However, this uses active code detection. The solution of the module is not ideal under certain conditions, especially when the user terminal is moving at a low speed and there is multipath fading, which may cause serious loss of system capacity.

Another alternative is to use the balanced single-user detection JD algorithm, also known as the MMSE-BLE-SD algorithm. For details of the algorithm, see A. Klein's titled "CDMA Mobile Wireless System Downstream." "Data detection algorithms specially designed for the downlink of CDMA mobile radio systems", published in the May 1997 issue of the IEEE International Conference on Automotive Technology (VTC), Vol. 1, No. 203- On page 207. Compared with the ZF-BLE and MMSE-BLE algorithms, the MMSE-BLE-SD algorithm has a slightly lower performance. The advantage is that it only needs to know the user terminal's own code. However, such an MMSE-BLE-SD algorithm must also know in advance the number of codes ACN (active code number) that are in the same state as the user terminal is allocated in the same time slot. Although the ACN can be calculated by a special algorithm in the user terminal, due to the large amount of calculation, the single user detection receiver complexity and power consumption are greatly increased.

The problems encountered in the above two schemes can, in fact, be solved by the base station transmitting information about the number of codes or active codes associated with each user terminal via the downlink channel.

For example: on the application date is January 13, 2003, the applicant is Royal Philips In the patent application entitled "Mobile Station capable of supporting advanced detection algorithms", the electronic patent company No. 03070755.6 proposes a kind of use by the base station via a common control channel such as BCH (broadcast channel). The method by which the terminal sends relevant code information. According to the method disclosed in the patent application, the code corresponding to the training sequence can be obtained from the allocation information of the training sequence. Such a method can be implemented in the case of a "default midamble" (i.e., in the case where the correspondence between the training sequence and the channel code is known). However, for the other two training sequences in the 3GPP TDD standard, namely: (i) the public training sequence, all users sharing the same time slot use the same training sequence; (ii) the upper layer application is allocated by signaling. The training sequence, at this time, there is no fixed correspondence between the training sequence and the code. For details, see 3GPP Technical Note 25.221 "Physical Channel and Transmission Channel to Physical Channel Mapping (TDD)" in the fourth edition of March 2001. In this case, the methods disclosed in the patent application still have certain limitations.

For example, in the patent application titled "Method and Apparatus for Supporting P2P Communication in TDD CDMA Communication System", the applicant is Royal Philips Electronics Co., Ltd., and the applicant's case number is PHCN030009, and the application number is 03110415.0. A method of broadcasting code allocation information (CAI) directly through a downlink common control channel (such as BCH). According to the method disclosed in the patent application, since the position of the common control channel in the radio frame or the subframe is fixed (for example, the BCH is transmitted in TS0), for each user terminal, it should be The CAI information is received and the CAI information is used for joint detection. However, using BCH to pass this information will encounter a problem: The repetition period of the BCH needs at least 80 ms (that is, 8 radio frames) or even larger (160, 320 or 640 ms, etc., determined by the upper layer). When the CAI information changes rapidly, the information may not be able to get the necessary updates; In addition, since the amount of CAI information is relatively large, if it must be transmitted in the BCH of each repetition period, it is bound to cause the BCH to be in a state of continuous overload.

In fact, CAI information changes only in the following three situations: First: at the beginning of the communication link, the base station assigns codes to new users; Second: during communication, other uses exist in the same time slot. The change of the user, for example, there are other users entering or leaving the time slot to cause a code allocation change; third: the user terminal that is communicating has switched to another cell, and the user terminal releases the code in the original cell. In these three cases, the change of CAI information only occurs within a certain period of time. If the system is stable, it is not necessary to send CAI information in the BCH of each repetition period. In addition, changes in CAI information will only affect individual user terminals in the same time slot without affecting user terminals operating in other time slots.

Therefore, it is necessary to provide CAI information in a more efficient manner so that the user terminal performs the joint detection algorithm using the CAI information.

It can be seen from the above analysis that for the TDD CDMA communication system, when the CAI information changes, it is a reasonable method to retransmit the changed CAI information in the corresponding downlink time slot.

An object of the present invention is to provide a method and apparatus for supporting downlink detection in a TDD CDMA communication system, which can be used only when the CAI information changes. The CAI information is sent, so that each user terminal that receives the CAI information can implement the ZF-BLE/MMSE-BLE joint detection algorithm by using the CAI information, thereby improving the communication quality of each user terminal.

Another object of the present invention is to provide a method and apparatus for supporting downlink for joint detection in a TDD CDMA communication system, by using the method and apparatus, to directly associate ACN information with a user associated with it The ACN information is sent, so that each user terminal that receives the ACN information can implement the MMSE-BLE-SD joint detection algorithm by using the ACN information, thereby improving the communication quality of each user terminal.

A method for supporting downlink joint detection in a TDD CDMA communication network system according to the present invention, comprising the steps of: (a) determining that code allocation information (CAI) in a downlink time slot is in a next TTI ( Whether there is a change in the transmission time interval; (b) if the code allocation information changes, the changed code allocation information is inserted as a specific control information into the service burst of the corresponding downlink time slot in the current TTI. One of the designated domains; (c) transmitting a service burst containing the particular control information to each of the user terminals in the downlink time slot via the downlink channel. Wherein, when a link is established with a user terminal, the initial code allocation information is sent by the network system to the user terminal.

A method for supporting joint detection of a downlink performed in a user terminal of a TDD CDMA communication system according to the present invention, comprising the steps of: (i) receiving a network system in a downlink time slot a traffic burst transmitted via the downlink channel; (ii) detecting whether the traffic burst includes code allocation information (CAI) of the downlink time slot in the next TTI; (iii) if included The code assigns information to extract the code allocation information; (iv) uses the code allocation information to perform the next stage joint detection algorithm to reduce signal interference.

A method for supporting single-user joint detection of a downlink performed by a network system in a TDD CDMA communication system according to the present invention includes the following steps: (a) determining that the uplink time slot is initiating Whether the number of user codes in the status (ACN) will change in the next TTI (transmission time interval); (b) if the number of user codes in the startup state changes, the number of changed activation codes is used as the specific control. Information is inserted into a designated domain of a traffic burst of a corresponding downlink time slot in the current TTI; (c) transmitting a traffic burst containing the specific control information to the downlink channel via the downlink channel Each user terminal in the gap. Wherein, when a link is established with a user terminal, the number of user codes that are initially in an activated state is sent by the network system to the user terminal.

A method for supporting single-user joint detection of a downlink performed in a user terminal of a TDD CDMA communication system according to the present invention, comprising the steps of: (i) receiving in a downlink time slot a service burst transmitted by the network system via the downlink channel; (ii) detecting whether the traffic burst includes the number of user codes (ACN) of the downlink time slot in the next TTI; Iii) extracting the number of the start code if the number of start codes is included; (iv) performing the next stage single user joint detection algorithm by using the number of start codes to reduce signal interference.

The content of the present invention will be described in detail below with reference to the accompanying drawings in the TD-SCDMA system. According to the technical solution of the present invention, when the above CAI information or ACN information When a change occurs, the base station inserts the changed CAI information or ACN information into the service burst to be transmitted, and transmits it to each user in the downlink time slot via the dedicated physical channel (DPCH) in the downlink time slot. The terminal UE, each user terminal UE performs the next stage of ZF-BLE/MMSE-BLE or MMSE-BLE-SD joint detection algorithm according to the detected CAI information or ACN information.

In order to more clearly describe the above solution of the present invention, in particular, the detailed process of how the base station inserts the changed CAI information or ACN information into the service burst to be transmitted will be described in more detail below with reference to FIGS. 1 to 3. First, the structure of the subframe and the service burst (ie, time slot) used by the TD-SCDMA system in the 3GPP standard will be briefly introduced.

In the TD-SCDMA system, the length of a radio frame is 10 ms (milliseconds), and each radio frame is further divided into two sub-frames, each of which has a length of 5 ms and is composed of 6400 chips. composition. As shown in FIG. 1, each subframe is composed of 7 service slots TS0-TS6 and 3 specific pilot slots, and each of the 7 service slots is composed of 864 chips, wherein the slots are composed of 864 chips. TS0 is always used to transmit downlink data, time slot TS1 is always used to transmit uplink data, and other time slots TS2-TS6 are used to transmit data in uplink or downlink, respectively; 3 specific The DwPTS in the pilot time slot is a downlink pilot time slot (96 chips), the UpPTS is an uplink pilot time slot (160 chips), and the GP is a guard period (96 chips). Each service slot is further divided into four domains, including: data domain 1 (352 wafers), training sequence domain (144 wafers), data domain 2 (352 wafers), and slot protection. Airspace GP (16 wafers), in which data domain 1 and data domain 2 are excluded It can also be used to carry some UE-specific control symbols, such as Transmitter Power Control (TPC), Synchronization Shift (Synchronization Shift), and Transmitter Format Combination Indicator TFCI (Transmitter Format Combination). Indicators, using these UE-specific control symbols, the base station can provide some control information to each user terminal UE.

2 shows a structural diagram of a subframe and a time slot loaded with a UE-specific control symbol. As shown in FIG. 2, the UE-specific control symbols are located on both sides of a training sequence (Midamble), that is, pilot symbols, and SS and TPC control symbols respectively occupy The position of part of the data symbol in the data field 2 in one of the time slots of each subframe, and the control symbol of the TFCI is divided into four parts, and the TFCIs of the first and second parts respectively occupy a radio frame. The position of one of the data frames in one of the sub-frames (same time slot as the SS and the TPC) and the data symbols in the data field 2, the third and fourth portions of the TFCI occupy the other The location of the data field 1 of the corresponding time slot of a sub-frame and the part of the data symbol of the data field 2. Since the TPC, SS and TFCI control symbols are located in the data field of the service time slot, like other data symbols, these control symbols are also encoded and spread before being sent to each user terminal UE, each user terminal. After receiving the data sent by the base station and containing the above control information, the UE must undergo some basic baseband processing to recover the information contained in the control symbols.

The structure of the radio frame and time slot used in the TD-SCDMA system is briefly described above. In a time slot, the specific structure of the traffic burst (ie, the allocation of service data and UE-specific control symbols) is used for the uplink in the time slot. It is determined by many factors such as the downlink and the Spreading Factor (SF). For example, according to the traditional TD-SCDMA protocol standard, the uplink spreading factor SF can be selected 1, 2, 4, 8, 16 Five different values, and the spread spectrum factor SF of the downlink can only select 1 and 16 values. The relationship between the number of data symbols S and the spread factor SF that can be accommodated according to the data field specified in the agreement S × SF = For 352 chips, an uplink time slot can contain 704, 352, 176, 88, and 44 symbols, respectively (two data fields are included in one slot), if a symbol is used to convert A QPSK (Quadrature Shift Keying) modulation rule of 2 bits (bits) corresponds to a different spreading factor SF, and an uplink time slot may have a number of bits of 1408 bits, respectively. 704 octets, 352 octets, 176 octets, and 88 octets; and corresponds to the 1 and 16 values of the downlink spreading factor SF, the downlink The number of data symbols that a time slot can contain is 704 and 44 symbols. According to the modulation rule of 1 symbol converted to 2 bits, When SF = 1, one downlink time slot has a number of bits of 1408 bits, and when SF = 16, one downlink time slot has a number of bits of 88 bits.

3 is a schematic diagram of a slot format of a downlink of a TD-SCDMA system in a conventional communication protocol, wherein the control symbol TFCI located in the fourth row has the number of bits occupied after encoding according to the presence or absence of TFCI information and the content of the TFCI information. _TFCI can be 0 bits, 4 bits, 8 bits, 16 bits, and 32 bits (bits, these bits are evenly distributed to a radio frame, ie two In the fifth line, the control symbols SS and TPC, when the spreading factor SF=16, if the time slot does not contain the information of SS and TPC, the number of bits occupied by SS and TPC is zero. If the time slot contains information of SS and TPC, the number of bits occupied by SS and TPC, N _SS and _NTPC are both 2-bit bits. Similarly, when the spreading factor SF=1, the bits occupied by SS and TPC are used. The number of elements N _SS and N _TPC may be 0 bit bits, both are 2 bit bits and are both 32 bit bits.

Taking the slot format with the slot format number 8 in FIG. 3 as an example, as shown in the figure, when the spreading factor SF=16, as described above, the number of bits included in the downlink slot is 88. Bit bit. In the downlink time slot, N _TFCI = 16 bits in the fourth row, according to the provisions in the agreement, the 16-bit is divided into 4 parts, and the 4 bits as the first or third part occupy the time slot. The 4-bit in the data field 1 as the 2nd or 4th part of the 4th bit occupies 4 bits in the data field 2 in the time slot; the N _SS and the N _TPC in the 5th line are both 2 bits. The two bits in the data field 2 in the time slot are respectively occupied. Since N _TFCI , N _SS and N _TPC must occupy the data domain for transmission, after inserting the UE-specific control symbols, there are 76 bits in the 88-bit time slot (88-bit-8 bits (N _TFCI) ) - 2 bits (N _SS ) - 2 bits (N _TPC ) = 76 bits ) for transmitting data services, where: 44 bits of data field 1 have 40 bits left (44 bits - 4 bits) Yuan (N _{TFCI of} Part 1 or Part 3 = 40 bits) is used to transmit data services. The data field of 44 bits has 36 bits left (44 bits - 4 bits (2nd or 4th) Part of the N _TFCI ) - 2 bits (N _SS ) - 2 bits (N _TPC ) = 36 bits) is used to transmit data services. The number of bits used to transmit the service data in the time slots and time slots in the data fields 1 and 2 after the insertion of the UE-specific control symbols are respectively N _data/Slot and N _{data/field in} lines 7, 8, and 9 of FIG. ₍₁₎ and N _{data/field (2)} .

Use private entity channel to transmit when CAI information or ACN information changes The method of the present invention for transmitting the changed CAI information or the ACN information to enable the user terminal UE to perform joint detection is similar to the method for inserting the UE-specific control symbols TFCI, SS and TPC in the data field of the service slot. The invention inserts a control symbol containing the changed CAI information or ACN information into the data field 1 or the data field 2 of the service time slot, and after encoding and spreading, transmits to the user terminal UE via the downlink channel.

4 is a structural diagram of a revised service burst including CAI or ACN information in a TD-SCDMA system according to the present invention, in which a CAI or ACN control symbol occupies a part of the data symbol in the data field 1 and is located at the 1st or Part 3: Location of some data symbols before TFCI (CAI/ACN information can also be located after TFCI in data field 2 or elsewhere in data field 1).

In the following, in conjunction with FIG. 5 to FIG. 8, based on the time slot structure shown in FIG. 4, when the downlink joint detection is implemented by using the ZF-BLE/MMSE-BLE algorithm and the MMSE-BLE-SD algorithm respectively, The specific process of inserting CAI information and ACN information into the data field of the service time slot.

First, use ZF-BLE or MMSE-BLE algorithm to achieve downlink joint detection

As described above, in the downlink of the TD-SCDMA system, the spreading factor SF has only two values of 1 and 16. When the SF is 1, it means that only one user is allocated in the time slot. In this case, there is no spreading frequency at all, so there is no problem of code allocation. Therefore, in the present invention, only the spreading factor SF is considered to be 16 Case.

When SF=16, there can be up to 16 codes in one time slot and 16 user codes at the same time. Therefore, for one time slot, 16 bits can be used (two One byte) to indicate the allocation of these 16 codes. As shown in the map of the code allocation situation shown in FIG. 5, the bit 15 to the bit 0 correspond to the code Code 15 to Code 0 used by the 16 user codes, respectively, wherein if Bit i=1, it corresponds to The code Code i is being used by a user terminal in the time slot; if Bit i=0, it means that the code Code i corresponding thereto has not been assigned to the user terminal. For example, when Bit 0 and Bit 5 in FIG. 5 are 1 and all other bits are 0, it means that only the corresponding codes Code 0 and Code 5 are being used by the user terminal, and other codes are not yet allocated for use. Terminal.

In the downlink service time slot, when the code allocation information (CAI) of 16 bits shown in FIG. 5 is transmitted by using the data field (the actual transmitted bit information changes after channel coding, where Assuming that the 16-bit original bit information is transmitted, the service slot format shown in FIG. 3 will be correspondingly changed. The modified format is as shown in FIG. 6. For convenience of comparison, the first row slot format numbers in FIG. 6 are denoted by n and n', respectively, wherein the column corresponding to the n-number is not inserted in the format of the code allocation information CAI, and the column corresponding to n' indicates the insertion of the CAI information. The subsequent slot format is marked in white and gray, respectively, and in any case the slot formats represented by n and n' do not appear at the same time.

Compared with FIG. 3, the fourth row N _CAI is added in FIG. 6 for indicating the code allocation information CAI. When N _CAI =0, it indicates that the code allocation status has not changed, and there is no need to transmit CAI information; when N _CAI =16 , indicating that the code allocation status has changed, for example, when one or more user terminals in the activated state leave the downlink time slot, the base station needs to reclaim the code resources released by the user terminal, or when one or more When the user terminal joins the downlink time slot, the base station needs to allocate code resources for the new user terminal, and when the base station needs to reallocate the code resources in the downlink time slot to make the downlink time slot When the resources are optimized, at this time, 16-bit CAI information needs to be transmitted to indicate the current usage status of each code corresponding to the CAI information in FIG. The number of bits used to transmit the service data in the data slots 1 and 2 in the downlink time slot and the downlink time slot after the CAI information is inserted is respectively N _data/Slot and N _data/field of the 8th, 9th, and 10th lines in FIG. ₍₁₎ and N _{data/field (2)} .

When the base station determines that the CAI information in the uplink time slot changes in the next TTI, inserting the 16-bit changed CAI information as specific control information into the current TTI and corresponding to the downlink time slot. The data field of the traffic burst of the downlink time slot (for example, the first data field shown in FIG. 4), and the CAI information and other service data, UE-specific control symbols TFCI, SS, and TPC (if UE-specific The control symbols are present together for spreading, and then the spread-spectrum service burst containing the specific control information is sent to each user in the downlink time slot via a downlink channel (eg, a dedicated physical channel DPCH) terminal.

When a user terminal in the downlink time slot receives a service burst transmitted by the base station via the DPCH, the user terminal first detects the service burst as in the method of detecting the UE specific control symbols TFCI, SS, and TPC. Whether the code includes the code allocation information CAI, if the CAI information is included, the code allocation information CAI is extracted, and according to the CAI information, the user terminal knows the allocation and use of the code corresponding to the CAI information shown in FIG. 5, and then, Using the detected code information, the user terminal prepares the joint detection algorithm for the next transmission time interval (TTI: Transmission Time Interval, the period in which the physical layer transmits the transmission block set by the null intermediate plane), namely: Place The extracted CAI information is used as the code allocation information of the downlink time slot in the next TTI; if the service burst received by the user terminal does not include the CAI information, it indicates that the code allocation status has not changed, and the user terminal can be based on the previous The code assigns usage status to perform the next phase of the joint detection algorithm.

One thing to note here is that since the CAI information inserted in the data field is the same as other business data, it needs to be spread before it can be sent. After receiving the information, the user terminal needs to use the advanced receiving algorithm (such as joint detection). Algorithm) can effectively detect CAI information. However, the joint detection algorithm needs to know the code information of the time slot in advance, so according to the above method of the present invention, it is impossible to use the CAI information transmitted in the current time slot to solve the data from the downlink in the current time slot. Expansion and decoding. Therefore, the CAI information of the present invention detected in the step of detecting the CAI information can only be used when the user terminal performs the joint detection algorithm in the next TTI (a TTI includes multiple subframes, A crossover period during which the CAI information does not change), and the initial CAI information can be initiated by the base station via the broadcast channel (BCH) when the communication link is established between the user terminal and the base station. Or other dedicated channel (DCH) sends the initial CAI information to the user terminal, so that the user terminal can use the initialized CAI information to perform joint detection when receiving the service burst transmitted in the subsequent downlink time slot. The algorithm sends to the user terminal to detect whether there is new changed CAI information.

Because the base station controls the allocation of radio resources, the base station notifies the user terminal allocated in the downlink time slot at the beginning of the communication link with the user terminal, and will foresee the current TTI. under The allocation change of the code in a TTI is inserted into the current TTI downlink time slot for transmission to each user terminal in the downlink time slot. In the communication technology, it should not be difficult for the base station to achieve.

As described above, when the user terminal detects that the network system changes the CAI information, the changed CAI information sent via the downlink can perform the ZF-BLE or MMSE-BLE algorithm using the received CAI information. .

Second, the MMSE-BLE-SD algorithm is used to achieve downlink joint detection

Different from the method of joint detection using ZF-BLE or MMSE-BLE algorithm, when using MMSE-BLE-SD algorithm, the UE does not need to know the detailed code allocation information in the time slot, but only needs to know that it is in the current time slot. The number of user codes for the active state (ACN)K. For this reason, four bits can be used to represent the 16 possibilities of the number of user codes in the time slot, as shown in FIG.

In the downlink service time slot, when the 4 bit ACN information shown in FIG. 7 is transmitted by using the data field (the actually transmitted bit information changes after the channel coding, it is assumed that the transmitted 4 is Bit original bit information), the service slot format shown in Figure 3 will produce corresponding changes, the modified format is shown in Figure 8. For convenience of comparison, the first row slot format numbers in FIG. 8 are also denoted by n and n', respectively, wherein the column corresponding to the n sequence is the format when the ACN information is not inserted, and the column corresponding to n' indicates the insertion of the ACN information. The slot format is marked in white and gray, respectively, and in any case the slot formats represented by n and n' do not appear at the same time.

Compared with FIG. 3, the fourth row N _AC is added in FIG. 8 to indicate the number of codes in the active state in the current time slot. When N _AC =0, the number of codes in the current time slot is activated. No change, no need to transmit ACN information; when N _AC = 4, it means that the number of codes in the current time slot is changed, and the ACN information of 4 bits needs to be transmitted. The downlink time slot after the ACN information is inserted, and the number of bits used for transmitting the service data in the data fields 1 and 2 in the downlink time slot are respectively N _data/Slot and N _{data of the} 8th, 9th, and 10th lines in FIG. 8. _/field(1) and N _{data/field(2) are} indicated.

When the base station judges that the number of codes in the uplink state in the uplink time slot changes in the next TTI, the ACN information after the change of the 4-bit is inserted as the specific control information into the current TTI and the downlink. The data field of the traffic burst of the downlink time slot corresponding to the slot (for example, the first data field shown in FIG. 4), and the ACN information and other service data, the UE-specific control symbols TFCI, SS, and TPC ( If the UE-specific control symbols are present, encoding and spreading together, then transmitting the spread-spectrum service burst containing the specific control information to the downlink time slot via the downlink channel (eg, dedicated physical channel DPCH) Each user terminal in the middle.

When a user terminal in the downlink time slot receives a service burst transmitted by the base station via the DPCH, the user terminal first detects the service burst as in the method of detecting the UE specific control symbols TFCI, SS, and TPC. Whether the ACN information is included in the transmission, if the ACN information is included, the activation code number ACN is extracted, and according to the ACN information, the user terminal prepares for the next TTI to perform a single user joint detection algorithm, that is, the extracted ACN information is The number of the start code of the downlink time slot in the next TTI; if the service burst received by the user terminal does not include the ACN information, the number of the start code does not change, and the user terminal can use the number of the previous start code. carried out A single-user joint detection algorithm in subsequent stages.

As with the above-mentioned ZF-BLE/MMSE-BLE algorithm, the ACN information of the present invention detected in the above step of detecting ACN information can only be used by the user terminal to perform single-user joint detection in the next TTI. The algorithm is used, and the original ACN information can be sent by the base station to the user terminal in an initialized form by the base station (at the beginning of the communication link with the user terminal).

As described above, when the user terminal detects that the network system changes in the ACN information, the changed ACN information sent via the downlink can perform the MMSE-BLE-SD algorithm using the received ACN information.

According to the above method of the present invention, when the CAI information or the ACN information changes during the communication process, the base station can insert the changed CAI information or the ACN information into the corresponding service burst in a specific control information form, so as to receive the The user terminal of the service burst can perform the joint detection algorithm according to the CAI information or the ACN information, thereby reducing the signal interference during the communication process; and for the user terminal not in the communication process, for example, the communication link is being established. Or when the communication link is being switched to another cell, the initialized CAI information or ACN information may be sent to the user terminal as part of the resource allocation message or the handover command message, so that the user terminal can allocate a message or a handover command according to the resource. The CAI information or ACN information in the message is used to perform the joint detection algorithm, thereby reducing signal interference during communication establishment and cell handover.

The above method of the present invention is applicable not only to a low bit rate TD-SCDMA system but also to a high wafer rate system such as 3.84 M chips/sec and 7.68 M chip/sec higher rate system.

The method for inserting CAI information or ACN information into a service burst in the form of specific control information and the method for detecting and utilizing CAI information or ACN information in a user terminal can be achieved not only by computer software but also by The computer hardware module of the software function is achieved, and can also be achieved by a combination of software and hardware.

When the method for supporting downlink joint detection of the present invention is implemented by using a hardware module, the combination of the network system and the user terminal is as shown in FIG. 9. The same components as those in the existing network system and user terminal are not shown in FIG.

When a user terminal in an activated state leaves the downlink time slot, or a new user terminal joins the downlink time slot, or the network system re-codes the code resources in the downlink time slot At the time of allocation, the judging unit 101 in the network system 100 judges that the code allocation information (CAI) in the downlink slot changes in the next TTI. The inserting unit 102 inserts the changed code allocation information as specific control information into a designated field of the traffic burst of the downlink time slot corresponding to the downlink time slot in the current TTI. Next, the transmitting unit 103 transmits the traffic burst containing the specific control information to each user terminal in the downlink time slot via the downlink channel. The initial code allocation information is sent to the user terminal by the sending unit 103 when the network system establishes a link with a user terminal.

The receiving unit 201 in the user terminal 200 receives the traffic burst transmitted by the network system via the downlink channel in one downlink time slot. The detecting unit 202 detects whether the downlink burst is included in the service burst. Code allocation information in a TTI. If the code allocation information is included, the extracting unit 203 extracts the code allocation information from the service burst, and the execution unit 204 performs the next stage ZF-BLE or MMSE-BLE joint detection algorithm. The initial code allocation information is the initial code allocation information received by the receiving unit 201 from the network system when establishing a link with the network system.

When a user terminal in an activated state leaves a downlink time slot or a new user terminal joins a downlink time slot, the determining unit 101 in the network system 100 determines the downlink. The number of user codes (CAN) in the active state in the time slot will change in the next TTI. The inserting unit 102 inserts the changed number of activation codes as a specific control information into a designated domain of the traffic burst of the downlink slot corresponding to the downlink slot in the current TTI. Then, the transmitting unit 103 transmits the service burst containing the specific control information to each user terminal in the downlink slot via one downlink channel. When the network system establishes a link with a user terminal, the sending unit 103 sends the number of user codes that are initially in the activated state to the user terminal.

The receiving unit 201 in the user terminal 200 receives a traffic burst transmitted by the network system via the downlink channel in a downlink time slot. The detecting unit 202 detects whether the service burst contains the number of user codes (CAN) in which the downlink time slot is in the startup state in the next TTI. If the number of the starting user terminals is included, the extracting unit 203 extracts the number of the starting code from the service burst, and the executing unit 204 performs the next stage MMSE-BLE-SD joint detecting algorithm. Wherein, the number of user codes that are initially active is received. The number of user codes initially received by the unit 201 from the network system when the unit 201 establishes a link with the network system.

Beneficial effects:

With the above description of the embodiments of the present invention in conjunction with the accompanying drawings, it can be seen that the method and apparatus of the present invention for supporting downlink joint detection in a TDD CDMA communication system are only in the downlink time slots. When the CAI information or the ACN information changes, the base station inserts the changed CAI information or ACN information into the service burst in the form of specific control information and sends it to each user terminal in the downlink time slot via the dedicated physical channel. Therefore, the BCH channel overload phenomenon that may be caused when the CAI information or the ACN information is sent in each BCH repetition period is avoided, and the user terminal in other time slots is read when the CAI information or the ACN information is sent through the common channel. Unnecessary calculations and power consumption caused by CAI information or ACN information.

Meanwhile, the method and apparatus for supporting downlink joint detection in a TDD CDMA communication system according to the present invention, wherein the user terminal can perform ZF-BLE according to the CAI information or ACN information included in the received service burst. /MMSE-BLE or MMSE-BLE-SD joint detection algorithm, therefore, can reduce signal interference during communication and improve communication quality of user terminals.

In addition, the method and apparatus of the present invention for supporting downlink joint detection in a TDD CDMA communication system does not rely on a training sequence information transfer code, and thus is not limited by a fixed relationship between a training sequence and a code, and is applicable. Allocation scheme for various training sequences in the 3GPP standard.

It should be understood by those skilled in the art that the method and apparatus for supporting downlink joint detection in the TDD CDMA communication system disclosed in the above-mentioned present invention can also be performed without departing from the content of the present invention. modify. Therefore, the scope of protection of the present invention should be determined by the content of the accompanying claims.

TS0-TS7‧‧‧ business gap

100‧‧‧Network System

101‧‧‧judging unit

102‧‧‧Insert unit

103‧‧‧Send unit

200‧‧‧user terminal

201‧‧‧ receiving unit

202‧‧‧Detection unit

203‧‧‧ extraction unit

204‧‧‧Execution unit

The present invention will be described in detail below with reference to the accompanying drawings and embodiments, wherein: FIG. 1 is a structural diagram of a sub-frame and a time slot used in a conventional TD-SCDMA system; and FIG. 2 is a UE-specific control symbol in a conventional TD-SCDMA system ( FIG. 3 is a schematic diagram of a time slot format of a downlink in a conventional TD-SCDMA system; FIG. 4 is a modified version of a TD-SCDMA system including CAI or ACN according to the present invention; FIG. 5 is a schematic diagram of a mapping relationship of code allocation information (CAI) of a TD-SCDMA system according to the present invention; FIG. 6 is a TD-SCDMA system according to the present invention, after inserting CAI information Schematic diagram of the slot format of the downlink; FIG. 7 is a schematic diagram of the number of user codes in the activated state indicated by the ACN information in the TD-SCDMA system according to the present invention; FIG. 8 is a TD-SCDMA system according to the present invention. Schematic diagram of the slot format of the downlink after the ACN information is inserted; FIG. 9 is used to support the downlink in the TDD CDMA communication system according to the present invention; The method of joint detection of roads is a block diagram achieved by a hardware module.

(no component symbol description)

Claims (20)

A method for supporting downlink joint detection in a TDD CDMA communication network system, the method comprising the steps of: determining a code allocation information (CAI) in a slot at a next transmission time interval (TTI) Whether the change is made, wherein the judgment includes one of the following judgments: when at least one of the activated user terminals leaves the downlink time slot, determining that the CAI is to be changed; when at least one user terminal When the downlink time slot is added, it is judged that the CAI is to be changed; when the spreading code resource in the downlink time slot is to be reallocated to achieve the resource optimization configuration in the downlink time slot, the CAI is judged. To be changed; and when at least one of the initiating user terminals performs a cell handover, determining that the CAI is to be changed; modifying the spreading code resource according to the changed CAI, the modification of the spreading code resource includes: And correcting the spreading code resource when the at least one user terminal in the startup leaves the downlink time slot; and assigning the extended code when the at least one user terminal joins the downlink time slot And redistributing the extended code resource when redistributing to achieve an optimized configuration of the resource, or when the at least one activated user terminal performs a cell transfer; only when the CAI changes, the change is made The CAI is inserted as a specific control information into the downlink time slot corresponding to the current TTI. In a specified one of the bursts, the changed CAI includes a spreading code resource associated with each of a plurality of user terminals using the downlink time slot, and the changed CAI is included in the spreading code resource Assigning, reallocating or correcting the CAI; transmitting the traffic burst containing the specific control information to each user terminal in the downlink time slot via a downlink channel, where The traffic burst of the user terminal includes all the spreading code resources associated with the user terminal using the downlink time slot. The method of claim 1, further comprising the step of: when the network system establishes a link with a user terminal, the network system transmits initial code allocation information to the user terminal. The method of claim 1, wherein the specific control information enables each user terminal in the downlink time slot to perform zero-forcing block linear equalization (ZF-BLE) and minimum mean square error block linear equalization (MMSE- BLE) One of two joint detection methods. A method for supporting joint detection of a downlink performed by a user terminal in a TDD CDMA communication network system, the method comprising the steps of: receiving a transmission by the network system via a downlink channel A burst of traffic in the slot of the link; detecting whether the CAI included in the burst of traffic is changed by a TTI under the downlink slot, wherein the detection includes the detection described below One of them: Detecting that the CAI is to be changed when at least one of the activated user terminals leaves the downlink time slot; and detecting that the CAI is to be changed when at least one user terminal joins the downlink time slot; Retrieving the spreading code resource in the downlink time slot to achieve the resource optimized configuration in the downlink time slot, detecting that the CAI is to be changed; and when at least one of the initiating user terminals executes a cell At the time of handover, detecting that the CAI is to be changed; modifying the spreading code resource according to the changed CAI, the modification of the spreading code resource includes: when the at least one activated user terminal leaves the downlink slot Correcting the spreading code resource; assigning the spreading code resource when the at least one user terminal joins the downlink time slot; and reallocating the optimized configuration of the resource, or using the at least one startup Relocating the spreading code resource when the terminal performs a cell handover; only when the traffic burst includes the CAI, the CAI is extracted, and the CAI includes all other multiples of the slot when the downlink is used. Make The CAI after the relevant terminal of the spread code resources of the CAI by Cuiqu contained in the resource allocated spreading code, redistribution or corrections; and using the CAI to the next phase of the joint detection algorithm to reduce signal interference. The method of claim 4, further comprising the step of: when the user terminal establishes a link with the network system, the user The terminal receives initial code allocation information from the network system. The method of claim 5, wherein the joint detection algorithm is one of a zero-forcing block linear equalization (ZF-BLE) method and a minimum mean square error block linear equalization (MMSE-BLE) method. A method for supporting single-user joint detection of a downlink in a TDD CDMA communication network system, comprising the steps of: determining whether the number of start codes (ACN) in a slot in a downlink time will be in a next TTI And wherein the determining comprises one of the following: determining that the CAI is to be changed when at least one of the initiating user terminals leaves the downlink slot; when at least one user terminal joins the When the downlink time slot is used, it is judged that the CAI is to be changed; when the spreading code resource in the downlink time slot is to be reallocated to achieve the resource optimization configuration in the downlink time slot, it is judged that the CAI is to be changed. And determining, when at least one of the initiating user terminals performs a cell handover, determining that the CAI is to be changed; modifying the spreading code resource according to the changed CAI, the modification of the spreading code resource comprising: when the at least one The spreading code resource is corrected when the user terminal in the startup leaves the downlink time slot; and the spreading code resource is allocated when the at least one user terminal joins the downlink time slot; Redistributing the extension when redistributing to achieve an optimized configuration of the resource, or when the at least one active user terminal performs a cell handover a code resource; if the number of the start code changes, the number of the changed start code is inserted as a specific control information into a specified domain of the traffic burst corresponding to the downlink time slot of the current TTI, The ACN includes a spreading code resource associated with a plurality of user terminals using the downlink time slot, the changed CAI including the CAI after the spreading code resource is allocated, reassigned, or corrected; the specific control will be included The information burst of the information is sent to each user terminal in the downlink time slot via the downlink channel, wherein the traffic burst sent to each of the plurality of user terminals includes using the downlink All the extension code resources associated with the user terminal in the link time slot. The method of claim 7, further comprising the step of: when the network system establishes a link with the user terminal, the network system transmits the initial number of activation codes to the user terminal. The method of claim 8, wherein the specific control information enables each user terminal in the downlink time slot to perform a single user-detected minimum mean square error block linear equalization (MMSE-BLE-SD) Joint detection method. A method for supporting single-user joint detection of a downlink performed by a user terminal in a TDD CDMA communication network system, the method comprising the steps of: receiving a time slot from the network system via a downlink a traffic burst transmitted by the lower downlink channel; detecting whether the downlink burst is included in the traffic burst The number of initiator codes (ACN) in the TTI, the ACN including spreading code resources associated with all other user terminals using the downlink slot, wherein the detection includes at least one of the following detections One: detecting that the CAI is to be changed when at least one of the activated user terminals leaves the downlink time slot; and detecting that the CAI is to be changed when at least one user terminal joins the downlink time slot; When the spreading code resource in the downlink time slot is to be reallocated to achieve the resource optimized configuration in the downlink time slot, detecting that the CAI is to be changed; and when the at least one activated user terminal When performing cell handover, detecting that the CAI is to be changed; modifying the spreading code resource according to the changed CAI, the modification of the spreading code resource includes: when the at least one activated user terminal leaves the downlink Correcting the spreading code resource when the time slot is used; assigning the spreading code resource when the at least one user terminal joins the downlink time slot; and reallocating the optimized configuration of the resource, or the When the user terminal in the startup performs a cell handover, the extension code resource is re-allocated; only when the traffic burst includes the ACN, the ACN is extracted, and the CAI extracted is included in the extension code. The resource is allocated, redistributed or corrected by the CAI; the next stage single-user joint detection algorithm is performed by using the number of the start code to reduce signal interference. The method of claim 10, wherein the user terminal receives the network system from the network system when the user terminal establishes a link with the network system before receiving the traffic burst transmitted by the network system The number of initial startup codes. The method of claim 11, wherein the joint detection method is a single user-detected minimum mean square error block linear equalization (MMSE-BLE-SD) method. A network system for supporting downlink joint detection includes: a judging unit configured to determine whether a code allocation information (CAI) in a slot in a downlink time band changes in a next TTI, wherein The determining includes one of the following determinations: when at least one of the initiating user terminals leaves the downlink slot, determining that the CAI is to be changed; when at least one user terminal joins the downlink In the time slot, it is judged that the CAI is to be changed; when the spreading code resource in the downlink time slot is to be reallocated to achieve the resource optimization configuration in the downlink time slot, it is judged that the CAI is to be changed; When at least one of the initiating user terminals performs a cell handover, determining that the CAI is to be changed; a resource unit configured to modify the spreading code resource according to the changed CAI, the modification of the spreading code resource includes Transmitting the spreading code resource when the at least one active user terminal leaves the downlink time slot; when the at least one user terminal joins the downlink time slot Reassigning the spreading code resource when the extended code resource is allocated; and redistributing to achieve an optimized configuration of the resource, or when the at least one activated user terminal performs a cell handover; And the grouping is configured to insert the changed code allocation information as a specific control information into a specified domain of the traffic burst corresponding to the downlink time slot of the current TTI only when the code allocation information is changed. The changed CAI includes a spreading code resource associated with each of a plurality of user terminals using the downlink time slot, the changed CAI being included in the spreading code resource being allocated, redistributed or corrected The CAI; a sending unit, configured to send a traffic burst containing the specific control information to each user terminal in the downlink time slot via a downlink channel, where the sending is sent to each user The traffic burst of the terminal includes all the spreading code resources associated with the user terminal using the downlink time slot. The network system of claim 13, wherein the sending unit transmits initial code allocation information to the user terminal when establishing a link with the user terminal. A user terminal for supporting downlink joint detection, comprising: a receiving unit configured to receive a downlink channel transmitted by a network system via a downlink time slot a traffic burst; a detecting unit configured to detect whether the traffic burst includes code allocation information (CAI) of the downlink time slot in a next TTI, the CAN includes and uses the downlink All other user terminal related spreading code resources of the time slot, wherein the detection includes the following detection At least one of the tests: detecting that the CAI is to be changed when at least one of the initiating user terminals leaves the downlink slot; and detecting when at least one user terminal joins the downlink slot Detecting that the CAI is to be changed; when the spreading code resource in the downlink time slot is to be reallocated to achieve a resource optimized configuration in the downlink time slot, detecting that the CAI is to be changed; and when the at least one When the user terminal in the startup performs a cell handover, it is detected that the CAI is to be changed; a resource unit is configured to modify the extension code resource according to the changed CAI, and the modification of the extension code resource includes: Correcting the spreading code resource when the at least one active user terminal leaves the downlink time slot; assigning the spreading code resource when the at least one user terminal joins the downlink time slot; and reallocating Re-allocating the spreading code resource when the optimized configuration of the resource is achieved, or when the user terminal in the at least one startup performs a cell handover; the culling unit is configured to only Hair bag The code allocation information is obtained by taking the code allocation information, and the CAI is included in the CAI after the extension code resource is allocated, re-allocated or corrected; an execution unit is configured to be allocated by using the code. The information performs the next phase of the joint detection algorithm to reduce signal interference. The user terminal of claim 15, wherein the receiving unit receives an initial code allocation from the network system when establishing a link with the network system News. A network system for supporting downlink single-user joint detection includes: a judging unit configured to determine whether the number of start codes (ACN) in the slot changes in the next TTI when the downlink is performed And the determining includes one of the following determinations: when at least one of the activated user terminals leaves the downlink time slot, determining that the CAI is to be changed; when at least one user terminal joins the downlink When the link time slot is determined, it is determined that the CAI is to be changed; when the spreading code resource in the downlink time slot is to be reallocated to achieve the resource optimized configuration in the downlink time slot, it is determined that the CAI is to be changed; And determining, when at least one of the initiating user terminals performs a cell handover, that the CAI is to be changed; a resource unit configured to modify the spreading code resource according to the changed CAI, the spreading code resource The modifying includes: correcting the spreading code resource when the at least one active user terminal leaves the downlink time slot; and assigning the expansion when the at least one user terminal joins the downlink time slot And re-allocating the extended code resource when the user terminal of the at least one activation performs a cell handover; and an insertion unit for only When the number of the startup code changes, the number of the changed startup code is inserted as a specific control information. In a specified domain of the traffic burst of the downlink time slot of the current TTI, the ACN includes a spreading code resource associated with a plurality of user terminals using the downlink time slot, and the changed CAI includes The CAI after the spreading code resource is allocated, reassigned or corrected; a transmitting unit configured to send a traffic burst containing the specific control information to the downlink slot through the downlink channel Each of the user terminals of the user terminal, wherein the traffic burst sent to each user terminal includes a spreading code resource associated with all of the user terminals using the downlink time slot. The network system of claim 17, wherein the sending unit sends the initial number of activation codes to the user terminal when establishing a link with the user terminal. A user terminal for supporting downlink single-user joint detection includes: a receiving unit configured to receive a downlink channel transmitted by a network system via a downlink link a traffic burst; a detection unit configured to detect whether the traffic burst includes an activation code number (ACN) of the downlink time slot in a next TTI, wherein the detection includes the following At least one of the detections: detecting that the CAI is to be changed when at least one of the initiating user terminals leaves the downlink slot; when at least one user terminal joins the downlink slot , detecting that the CAI is going to change; when the extension code resource in the slot is to be re-established Detecting that the CAI is to be changed when the resource optimization configuration in the downlink time slot is reached; and detecting that the CAI is to be changed when the at least one activated user terminal performs a cell handover; a resource unit, configured to modify the spreading code resource according to the changed CAI, where the modification of the spreading code resource includes: when the at least one activated user terminal leaves the downlink time slot, correct the a spreading code resource; when the at least one user terminal joins the downlink time slot, allocating the spreading code resource; and reallocating to achieve an optimized configuration of the resource, or performing the at least one active user terminal When a cell is handed over, the spreading code resource is reassigned; a culling unit is configured to extract the ACN only when the traffic burst includes the ACN, and the ACN includes and uses the downlink a spreading code resource associated with all other user terminals of the slot, wherein the CAI is included in the CAI after the spreading code resource is allocated, re-allocated or corrected; an execution unit is configured to utilize the startup Number of codes The next stage single-line user joint detection algorithm to reduce signal interference. The user terminal of claim 19, wherein the receiving unit receives the initial number of activation codes from the network system.