WO2003077458A1 - Procede et dispositif de construction du systeme td-las - Google Patents

Procede et dispositif de construction du systeme td-las Download PDF

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Publication number
WO2003077458A1
WO2003077458A1 PCT/CN2002/000143 CN0200143W WO03077458A1 WO 2003077458 A1 WO2003077458 A1 WO 2003077458A1 CN 0200143 W CN0200143 W CN 0200143W WO 03077458 A1 WO03077458 A1 WO 03077458A1
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WIPO (PCT)
Prior art keywords
code
tpc
las
synchronization
channel
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PCT/CN2002/000143
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English (en)
Chinese (zh)
Inventor
Daoben Li
Yongsheng Zhang
Li Fang
Yongzhong Zou
Yonghui Li
Yan Gao
Xiaohua Liu
Huixia He
Jiangbo Dong
Chundi Xiu
Yuan Zhang
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Linkair Communications Inc.
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Application filed by Linkair Communications Inc. filed Critical Linkair Communications Inc.
Priority to PCT/CN2002/000143 priority Critical patent/WO2003077458A1/fr
Priority to CN02827048.7A priority patent/CN1613221A/zh
Priority to AU2002238361A priority patent/AU2002238361A1/en
Publication of WO2003077458A1 publication Critical patent/WO2003077458A1/fr

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B7/00—Radio transmission systems, i.e. using radiation field
    • H04B7/24—Radio transmission systems, i.e. using radiation field for communication between two or more posts
    • H04B7/26—Radio transmission systems, i.e. using radiation field for communication between two or more posts at least one of which is mobile
    • H04B7/2662—Arrangements for Wireless System Synchronisation
    • H04B7/2668—Arrangements for Wireless Code-Division Multiple Access [CDMA] System Synchronisation

Definitions

  • the present invention relates to the field of electrical communication technology, and in particular to a method and device for constructing a TD-LAS system.
  • the traditional CDMA mobile communication system uses CDMA technology based on long pseudo-random codes (PN) and short orthogonal codes (Wal sh or Golden sequences).
  • PN pseudo-random codes
  • Wal sh or Golden sequences short orthogonal codes
  • the communication capacity and spectrum efficiency of a multi-user wireless communication system based on CDMA (Code Division Mul t iple Access) technology are very closely related to the relevant characteristics of the spread-spectrum multiple access code used.
  • Related correlation characteristics include the auto-correlation and cross-correlation characteristics of spread spectrum multiple access codes.
  • the traditional CDMA system because its address code design is limited by the theoretical Welch bound, under mobile wireless propagation conditions, there are severe Inter Symbol Interference, Multiple Access Interference (Mul t iple Access Interference), and neighbors.
  • CDMA Code Division Multiple Access
  • CDMA system adopts a networking scheme with frequency reuse as one, that is, different cells use the same frequency Rate. In order to distinguish different cells and reduce neighboring cell interference, it is necessary to use code space for networking. In traditional CDMA, different offsets of long PN codes are used for networking design between cells.
  • the design of the wireless frame structure greatly depends on the basic technology of the physical layer.
  • the frame structure of the traditional CDMA system is designed based on the PN code and Walsh code.
  • the wireless transceiver is the basic part of the system.
  • the baseband filter is a key technology.
  • the baseband filter used is designed based on the characteristics and characteristics of PN codes and 3 ⁇ 4l sh codes; it is based on baseband shaping filters designed to support voice services and low-dimensional modulation methods such as BPSK, QPS / DQPSK, GMS It is difficult to support high-speed data services for future mobile communication systems.
  • turbo code channel coding technology is a key technology.
  • PCCC parl lel concatenated convolutional code
  • SCCC sparser ia l concatenated convolutional code
  • Their corresponding decoding algorithms are soft-in and soft-out iterative MAP decoding algorithms, LOG-MAP (Logari thm-Maximum A Pos ter ior) or simplified algorithms such as MAX-LOG-MAP, SOVA (Soft-In-Sof t-Out Viterbi Algori thm), etc.
  • the algorithm corresponds to a complex decoder structure, high cost, slow processing speed, and large delay.
  • HARQ Hybrid Auto Repeat Repeat
  • RCPT / HARQ
  • HARQ Random Auto Repeat Repeat
  • PCCC Physical layer error control
  • the implementation of type I system is relatively simple, but under the condition of guaranteeing the same QoS (Quality of Service), the system efficiency is obviously inferior to that of type II system.
  • the Chase combination method cannot provide effective system throughput at high channel error rates, and utilizes IR (Incremental Redundancy)
  • IR Intelligent Redundancy
  • Transmit diversity technology can effectively improve the efficiency of the system and improve the performance of the system under fading channels.
  • TSTD Time Switched Transmitter Diversity
  • STTD Space Time Transmitter Diversity
  • OTD Orthogonal Transmitter Diversity
  • STD Selective Transmitter Diversity
  • the first three are open-loop modes, and STD uses the half-open-loop mode, that is, the transmit diversity of the base station needs to select the downlink antenna according to the uplink data sent by the mobile station, and it depends on the continuous pilot signal to perform Channel estimation and demodulation, so the base station also needs to provide downlink instructions to inform the mobile station which pilot channel should be used for demodulation.
  • the above-mentioned existing transmit diversity methods have the following disadvantages: For example, when an open-loop transmit diversity method is used, the improvement of the system's receiving performance is not ideal, the accuracy is not high enough, and it is very sensitive to the environment.
  • the open-loop transmit diversity method is more complicated to implement. Because it needs to rely on continuous pilot signals for channel estimation and demodulation, and then provides downlink instructions according to this, it is more complicated to implement and has a limited application range.
  • the CDMA system requires each user to maintain synchronization when arriving at the base station, so uplink synchronization is a key technology.
  • uplink synchronization is a key technology.
  • traditional CDMA systems especially synchronous CDMA systems (such as TD-SCDMA), for mobile stations, the prerequisite for system access is to complete downlink synchronization.
  • downlink synchronization is achieved by sliding correlation of PN codes and searching all possible PN code phases to complete synchronization acquisition.
  • the networking scheme of PN code and Walsh code is used. Due to the difference in the transmission rate required for voice and data services (long code spreading is used for voice and short code spreading is used for data), once the codeword on the trunk is allocated to the MS, The codeword on its corresponding branch will no longer be usable.
  • the FDD mode of the WCDMA system uses this dynamic 0VSF allocation strategy. Based on the design idea of interference white noise, the random assignment of Walsh codes by each cell or sector is better.
  • Dynamic channel allocation is divided into slow and fast dynamic channel allocation.
  • the CDMA2000 system does not use dynamic channel allocation technology, because it uses PN code offset to implement networking. It can only fixedly allocate a PN code offset to each cell during network planning.
  • the TDD mode of WCDMA system uses Dynamic (slow and fast) channel allocation techniques are introduced.
  • channel estimation technology In order to compensate the signal fading and distortion of the mobile system in the communication channel, channel estimation technology must be used. In a fading channel, the accuracy of the channel estimation directly affects the performance of the system. In a conventional CDMA system, a continuous pilot channel estimation method and a dedicated pilot channel estimation method are used. The channel estimation method using continuous pilots needs to occupy a dedicated channel, so the transmit power of the transmitter needs to be increased. Therefore, continuous pilots are only used for downlink communications (from base stations to mobile stations) in synchronous CDMA systems, while dedicated pilots Frequency channel estimation method, which is greatly affected by the moving speed of the mobile station. Summary of the Invention
  • the object of the present invention is to provide a method and device for constructing a TD-LAS system. It is a mobile communication system based on LAS-CDMA core technology and oriented to "all IP".
  • the auto-correlation and cross-correlation characteristics of LAS codes form a unique "Zero interference window", which is a feature not found in other traditional CDMA communication systems.
  • the invention is used to solve the problem of reducing interference between adjacent cells and improving system capacity and spectrum efficiency; it can effectively support large area coverage in a time division duplex (TDD) working mode, and can also rate the system's uplink and downlink services.
  • TDD time division duplex
  • Digital baseband signal waveform distortion is small, and for digital baseband signal waveform distortion using high-dimensional modulation methods such as 8 PSK, 16PSK, 32PSK, 16QAM, 32QAM, 64QAM, 64 PSK, it can support digital mobile communication systems using high Dimensional modulation methods, such as 8 PSK, 16PSK, 32PSK, 16QAM, 32QAM, 64QAM, 64 PSK, etc., realize high-speed, high-frequency data transmission with high spectral efficiency, and have less interference between adjacent channels in the system, and also interfere with other communication systems. Smaller, can improve spectrum efficiency and system capacity of mobile communication systems, especially high-speed mobile communication systems This will lay the foundation for establishing a large-capacity wireless digital communication system capable of providing high-data transmission services.
  • the corresponding codec of the present invention has a simple structure, low complexity, fast processing speed, and small time delay. It can obtain higher channel coding gain for high coding efficiency and short frames, and is used for simultaneous correction in practical applications. Random errors and burst errors are particularly suitable for interfering with complex channel environments; simplifying encoding and decoding equipment and speeding up the decoding processing speed, thereby ensuring system performance and reducing the complexity of system implementation. Get better decoding performance without increasing the complexity of the algorithm, and can support more types of subcodes. Further, the TP-ARQ system can obtain the highest coding gain and system efficiency with the lowest system complexity possible.
  • the invention can improve the transmit diversity performance, resist fading, and increase the accuracy of reverse synchronization. The invention shortens the synchronization acquisition time and improves the performance of cell search and target cell search.
  • the invention is used to overcome the "far-near effect" in traditional CDMA systems. Able to make more thorough and reasonable power adjustments, further reduce the transmit power of mobile phones and base stations, reduce the power consumption of mobile phones, increase the standby time of mobile phones, which will further reflect the technology "people-oriented, environment-oriented” Characteristics.
  • the invention can greatly reduce the interference of neighboring cells and the interference to neighboring cells or sectors. It makes it possible for different cells to use different time slot allocation patterns. It can save the transmission power of the signal, can effectively overcome the effects of deep fading on the amplitude and phase of the signal, and can ensure that higher-dimensional modulation is applied in a high-speed mobile environment. At the same time, the performance of the system is less affected by the moving speed of the mobile station, that is, it is less affected by the fast fading caused by Doppler frequency shift, so it can effectively overcome the effects of deep fading caused by high speed movement on the signal amplitude and phase. At the same time, applying this method can guarantee the application of higher-dimensional modulation methods such as 8 PSK, 16PSK, 32PSK, 16QAM, 32QAM, 64QAM 64PSK in a high-speed mobile environment.
  • a method for constructing a TD-LAS system includes: adopting a LAS code as a spread-spectrum multiple access code; adopting an LA code and an LS code for networking between cells; a subframe of a wireless frame structure is composed of an LA code and an LS code; The uplink synchronization access pulse is formed based on the LS code; the downlink synchronization subframe is formed of the LA code and the LS code.
  • the networking between the cells using the LA code and the LS code includes: codewords with the same spreading length and split-spreading for high-rate services; the size of the zero correlation window between different LS code groups is different; Or, the more regular the LS code allocation in the sector is, the better the code group with a large zero correlation window is used as much as possible to reduce interference to neighboring cells or sectors.
  • the composition of the uplink synchronization access pulse based on the LS code includes:
  • the spread-spectrum code LS code has a cross-correlation zero window characteristic.
  • a standard time is set at the uplink synchronization channel receiver of the base station, and an uplink synchronization success gate P is preset. That is, when the difference between the time when the uplink synchronization pulse arrives at the base station and the standard time is less than the preset uplink synchronization success threshold, the uplink synchronization is considered successful; otherwise, the uplink synchronization is still considered unsuccessful, and the uplink synchronization process needs to continue. Upstream bit synchronization and frame synchronization are completed simultaneously.
  • the downlink synchronization subframe is composed of LA code and LS code.
  • the LS + LA code group has excellent auto-correlation and cross-correlation characteristics and can be directly used for synchronization acquisition. A matched filter matching a specific channel is used. You can search the entire set of LS + LA code groups for cell search and target cell search. According to the characteristics of LS + LA codes, different synchronization sequences implemented by different LA pulse coding methods for the same LS code sequence can be searched in parallel. No need to increase hardware resources.
  • the method further includes: encoding using a TPC code.
  • the method further includes: using TPC code decoding.
  • the method further includes: encoding using a TPC code, and decoding using TPC iterative decoding based on a subcode adjoint.
  • the method further includes: using TP-ARQ based on TPC coding to perform error control.
  • the method further includes: encoding using a TPC code, decoding using a TPC iterative decoding based on a subcode adjoint, and performing error control using TP-ARQ based on TPC coding.
  • the method further includes: filtering using a finite impulse response baseband filter.
  • the method further includes: encoding using a TPC code, decoding using a TPC iterative decoding based on a subcode adjoint, performing error control using TP-ARQ based on TPC encoding, and filtering using a finite impulse response baseband filter .
  • the method further includes: using STSTD (Smart Selective Transmit Diversity) transmission diversity.
  • the method further includes: encoding using TPC code, decoding using TPC iterative decoding based on subcode adjoint, error control using TP-ARQ based on TPC encoding, and filtering using a finite impulse response baseband filter.
  • STSTD transmit diversity.
  • the method further includes: not only low-dimensional modulation methods such as BPSK, QPSK / DQPSK, GMSK, etc., but also high-dimensional modulation methods can be used, the high-dimensional modulation methods may be 8 PSK, 16PSK, 32PSK, 16QAM , 32QAM, 64QAM, 64 PSK, etc.
  • the method further includes: encoding using TPC code, decoding using TPC iterative decoding based on subcode adjoint, error control using TP-ARQ based on TPC encoding, and filtering using a finite impulse response baseband filter.
  • STSTD transmit diversity not only low-dimensional modulation methods such as BPSK, QPSK / DQPSK, GMSK, but also high-dimensional modulation methods can be used for modulation.
  • the high-dimensional modulation methods can be 8 PSK, 16PSK, 32PSK, 16QAM, 32QAM, 64QAM, 64 PS, etc.
  • the method further includes: performing an operation by matching the receiving end of the uplink synchronization channel with a corresponding matched filter.
  • the method further includes: encoding using a TPC code, decoding using a TPC iterative decoding based on a subcode adjoint, performing error control using TP-ARQ based on TPC encoding, and filtering using a finite impulse response baseband filter
  • STSTD transmit diversity not only ⁇ -dimensional modulation methods such as BPSK, QPSK / DQPSK, GMSK, etc., but also high-dimensional modulation methods can be used.
  • the high-dimensional modulation methods can be 8 PSK, 16PSK, 32PSK, 16QAM, 32QAM, 64QAM, 64 PSK, etc., the receiving end of the uplink synchronization channel is matched with a corresponding matched filter for calculation.
  • the method further includes: using power adjustment.
  • the method further includes: encoding using TPC code, decoding using TPC iterative decoding based on subcode adjoint, error control using TP-ARQ based on TPC encoding, and filtering using a finite impulse response baseband filter.
  • STSTD transmit diversity not only low-dimensional modulation methods such as BPSK, QPSK / DQPSK, GMSK, but also high-dimensional modulation methods can be used.
  • the high-dimensional modulation methods can be 8 PSK, 16PSK, 32PSK, 16QAM, 32QAM, 64QAM, 64 PSK, etc.
  • the receiving end of the uplink synchronization channel is equipped with corresponding matched filters for calculation, and power adjustment is used.
  • the method further includes: using hard handover for handover.
  • the hard handover includes: in a TD-LAS system, each cell or sector sends continuous pilot signals with the same LS code and different LA codes, and the MS contains LA code information of each neighboring cell or sector; MS Only maintain communication with one cell or sector. When the service performance decreases to a certain level, the MS will turn on another downlink synchronization receiver, poll the downlink synchronization signal strength of other cells or sectors, and calculate the synchronization between different cells. Time deviation; After receiving the handover command from the network, the MS will immediately interrupt communication with the current cell or sector, and use the time deviation measurement value to directly send uplink service information to the new cell or sector and establish a downlink communication link.
  • the BS Track and adjust the uplink synchronization through the uplink pilot signal; if the uplink service information fails the CRC check for a period of time, the MS will stop the communication of the uplink service, send the uplink synchronization pulse in the idle access slot, and re-establish with the new cell Uplink synchronization; hard handover is not seamless.
  • the method further includes: encoding using TPC code, decoding using TPC iterative decoding based on subcode adjoint, error control using TP-ARQ based on TPC encoding, and filtering using a finite impulse response baseband filter.
  • STSTD transmit diversity not only low-dimensional modulation methods such as BPSK, QPSK / DQPSK, GMSK, but also high-dimensional modulation methods can be used.
  • the high-dimensional modulation methods can be 8 PSK, 16PSK, 32PSK, 16QAM, 32QAM, 64QAM, 64 PSK, etc.
  • the receiving end of the uplink synchronization channel is equipped with a corresponding matched filter for calculation, power adjustment, and hard handover for handover.
  • the method further includes: using dynamic channel allocation for channel resource allocation.
  • the method further includes: encoding using TPC code, decoding using TPC iterative decoding based on subcode adjoint, error control using TP-ARQ based on TPC encoding, and filtering using a finite impulse response baseband filter.
  • STSTD transmit diversity not only low-dimensional modulation methods such as BPSK, QPS / DQPSK, GMSK, but also high-dimensional modulation methods can be used.
  • the high-dimensional modulation methods can be 8 PSK, 16PSK, 32PSK, 16QAM, 32QAM, 64QAM, 64 PSK, etc.
  • the receiving end of the uplink synchronization channel is equipped with corresponding matched filters for calculation, power adjustment, hard handover for switching, and dynamic channel allocation for channel resource allocation.
  • the method is characterized in that it further comprises: adopting dual channel channel estimation.
  • the method further includes: encoding using TPC code, decoding using TPC iterative decoding based on subcode adjoint, error control using TP-ARQ based on TPC encoding, and filtering using a finite impulse response baseband filter.
  • STSTD transmit diversity not only low-dimensional modulation methods such as BPSK, QPSK / DQPSK, GMSK, but also high-dimensional modulation methods can be used.
  • the high-dimensional modulation methods can be 8 PSK, 16PSK, 32PSK, 16QAM, 32QAM, 64QAM, 64 PSK, etc.
  • the receiving end of the uplink synchronization channel is matched with a corresponding matched filter for calculation, power adjustment is adopted, hard handover is used for switching, dynamic channel allocation is used for channel resource allocation, and dual channel channel estimation is used.
  • the present invention also provides a device for constructing a TD-LAS system, which is composed of a transmitter and a receiver, wherein the transmitter includes at least a spread spectrum device using a LAS code as a spread spectrum multiple access code; the receiving The machine includes at least a despreading device based on the LAS code as a spread spectrum multiple access code;
  • the information from the source is transmitted at least after spreading by a spreading device that uses LAS code as the spreading multiple access code To the channel; the information received by the sink has at least been despread by a despreading device based on the LAS code as a spread spectrum multiple access code.
  • the information sent by the source can be spread by the spreading device using LAS code as the spreading multiple access code, and framed by the wireless frame framing device, and then transmitted to the channel; the information received by the sink can be deframed by the wireless frame framing device.
  • Despreading performed by a despreading device based on the LAS code as a spread spectrum multiple access code.
  • the transmitter may further include a wireless frame framing device and a finite impulse response baseband filter; the receiver may further include a wireless frame deframe device and a matched filter; wherein the subframe of the wireless frame structure is composed of a LA code And LS code;
  • the information sent by the source can be transmitted to the channel after being spread by a spread-spectrum device using LAS code as the spread-spectrum multiple-access code, framed by the wireless frame framing device, and filtered by a finite impulse response baseband filter; the information received by the sink can be Filtering by a matched filter, deframing by a radio frame deframing device, and despreading by a despreading device based on a LAS code for a spread spectrum multiple access code.
  • the information sent by the source can be encoded by a TPC encoder, spread by a spreading device using LAS code as the spread spectrum multiple access code, framed by a wireless frame framing device, and filtered by a finite impulse response baseband filter and transmitted to the channel;
  • the received information can be filtered by a matched filter, deframed by a wireless frame deframe device, despread by a despreading device based on a LAS code for a spread spectrum multiple access code, and decoded by a TPC decoder.
  • the transmitter may further include a wireless frame framing device, a finite impulse response baseband filter, and a TPC encoder; the receiver may further include a wireless frame deframe device, a matched filter, and a sub-code-based Random TPC iterative decoder; the sub-frame of the wireless frame structure is composed of LA code and LS code; the information sent by the source can be encoded by a TPC encoder, and the spreading device uses LAS code as the spreading multiple access code.
  • the transmitter may further include a wireless frame framing device, a finite impulse response baseband filter, a TPC encoder, and a modulator; the receiver may further include a wireless frame framing device, a matched filter, and a subcode-based device.
  • TPC iterative decoder and demodulator; wherein the subframes of the wireless frame structure are composed of LA codes and LS codes;
  • the information sent by the source can be encoded by the TPC encoder, the modulation of the modulator, the spreading device using the LAS code as the spread spectrum multiple access code, the wireless frame framing device, and the finite impulse response baseband filter. Transmitted to the channel; the information received by the sink can be filtered by matched filters, deframed by the radio frame deframing device, despread by the despreading device based on the LAS code for the spread spectrum multiple access code, corresponding to the high-dimensional modulation method Demodulation of a demodulator and decoding of a TPC iterative decoder based on subcode adjoint.
  • the transmitter may further include a wireless frame framing device, a finite impulse response baseband filter, a TPC encoder, a modulator applicable to a high-dimensional modulation mode, a CRC checker, and a HARQ controller; the receiving The machine may further include a wireless frame de-frame device, a matched filter, a TPC iterative decoder based on the sub-code adjoint, a demodulator, and a CRC checker; wherein the sub-frame of the wireless frame structure is composed of a LA code and an LS code;
  • the information sent by the source can be verified by the CRC checker, TPC encoder coding, modulation of the modulator, spreading by the spreading device using the LAS code as the spreading multiple access code, framing by the wireless frame framing device, limited burst
  • the impulse response baseband filter is transmitted to the channel after filtering; the information received by the sink can be filtered by the matched filter Wave, wireless frame deframe device deframe, despreading based on LAS code for spread spectrum multiple access code despreading device, demodulator demodulation, TPC iterative decoder based on subcode adjoint Code, CRC checker;
  • the receiver's CRC checker can feed back an automatic retransmission request to the HARQ controller for error control and retransmission at the sender.
  • the transmitter may further include a wireless frame framing device, a finite impulse response baseband filter, a TPC encoder, a modulator, a CRC checker, a HARQ controller, and a synchronization device.
  • the receiver may further include a wireless device.
  • Frame de-frame device matched filter, sub-code accompanying TPC iterative decoder, demodulator, CRC checker, and synchronization device; wherein the sub-frame of the wireless frame structure is composed of LA code and LS code; source The information sent can be verified by CRC checker, TPC encoder coding, modulation of modulator, spreading by spreading device using LAS code as spread spectrum multiple access code, framing by wireless frame framing device, limited impulse response Baseband filter filtering and transmission to the channel after synchronization by the synchronization device; information received by the sink can be synchronized by the synchronization device, filtering by the matched filter, deframing by the wireless frame deframing device, and spread-spectrum multiple access code based on the LAS code Despreading performed by the despreading device, demodulation of the demodulator, decoding of the TPC iterative decoder based on the subcode adjoint, and check of the CRC checker; the CRC checker of the receiver can feed back the automatic
  • the transmitter may further include a radio frame framing device, a finite impulse response baseband filter, a TPC encoder, a modulator, a CRC checker, a HARQ controller, a synchronization device, and a STSTD transmission diversity device; the receiving The machine may further include a wireless frame de-frame device, a matched filter, a TPC iterative decoder based on subcode adjoint, a demodulator, a CRC checker, a synchronization device, and a STSTD receiving diversity device; wherein the wireless frame structure is a subframe Consists of LA code and LS code;
  • the information sent by the source can be verified by the CRC checker, TPC encoder coding, modulation of the modulator, spreading by the spreading device using the LAS code as the spreading multiple access code, framing by the wireless frame framing device, limited burst Impulse response baseband filter filtering, STSTD transmit diversity device after transmission diversity, synchronization device after synchronization Transmitted to the channel;
  • the information received by the sink can be synchronized by the synchronization device, the reception diversity of the STSTD reception diversity device, the filtering of the matched filter, the de-frame by the wireless frame de-frame device, and the reception of the spread-spectrum multiple access code based on the LAS code Diversity and despreading performed by the despreading device, demodulation of the demodulator, decoding of the TPC iterative decoder based on the subcode adjoint, and check of the CRC checker; the CRC checker of the receiver can feedback automatically
  • the retransmission request is sent to the HARQ controller for error control and
  • the transmitter may further include a wireless frame framing device, a finite impulse response baseband filter, a TPC encoder, a modulator, a CRC checker, a HARQ controller, a synchronization device, a STSTD transmission diversity device, and a power adjustment device.
  • the receiver may further include a wireless frame de-frame device, a matched filter, a subcode-based TPC iterative decoder, a demodulator, a CRC checker, a synchronization device, and a STSTD reception diversity device;
  • the subframe of the frame structure is composed of LA code and LS code;
  • the information sent by the source can be verified by the CRC checker, TPC encoder coding, modulation of the modulator, spreading by the spreading device using the LAS code as the spreading multiple access code, framing by the wireless frame framing device, limited burst Impulse response baseband filter filtering, STSTD transmit diversity device transmit diversity, power adjustment device power adjustment, and power transmission to the channel; information received by the sink can be synchronized by the synchronization device, STSTD receive diversity device reception diversity, matched filtering Filter, deframe by wireless frame deframe device, receive diversity based on LAS code as spread spectrum multiple access code, despread by despread device, demodulator demodulation, TPC iteration based on subcode adjoint Decoder's decoding, CRC checker's check; Receiver's CRC checker can feed back the automatic retransmission request to the HARQ controller for error control and retransmission at the sender.
  • the present invention provides a method and device for constructing a TD-LAS system. It is a "all-IP" -oriented mobile communication system based on LAS-CDMA core technology.
  • the auto-correlation and cross-correlation characteristics of LAS codes form a unique ""Zero interference window", which is the spread spectrum multiple access used by other traditional CDMA communication systems Features that the code does not have.
  • the invention greatly reduces interference between adjacent cells, improves system capacity and spectrum efficiency; can effectively support large area coverage in a time division duplex (TDD) working mode, and can also provide system uplink and downlink services.
  • TDD time division duplex
  • the digital baseband signal waveform of the modulation method has less distortion, and the digital baseband signal waveform distortion using high-dimensional modulation methods such as 8 PSK, 16PSK, 32PSK, 16QAM, 32QAM, 64QAM, 64 PSK is small, which can support the adoption of digital mobile communication systems.
  • High-dimensional modulation methods such as 8 PSK, 16PSK, 32PSK, 16QAM, 32QAM, 64QAM, 64 PSK, etc., realize high-speed data transmission with high spectral efficiency, and have less interference between adjacent channels in the system, and at the same time interfere with other communication systems It is also relatively small, which can improve the spectral efficiency and system capacity of mobile communication systems, especially high-speed mobile communication systems. Since a large capacity and a wireless digital communication system can provide high data transmission services number basis;
  • the corresponding codec of the present invention has a simple structure, low complexity, fast processing speed, and small time delay. It can obtain higher channel coding gain for high coding efficiency and short frames, and is used for simultaneous correction in practical applications. Random errors and burst errors are particularly suitable for interfering with complex channel environments; the coding and decoding equipment is simplified, and the decoding processing speed is accelerated, thereby reducing the complexity of system implementation while ensuring system performance. It can obtain better decoding performance without increasing the complexity of the algorithm, and can support more types of subcodes. Further, the TP-ARQ system can obtain the highest coding gain and system efficiency with the lowest system complexity possible.
  • the invention can also improve the transmit diversity performance well, can well resist fading, and increase the accuracy of reverse synchronization.
  • the invention shortens the synchronization acquisition time and improves the performance of cell search and target cell search.
  • the present invention does not have the "far-near effect" in the traditional CDMA system. Therefore, power can be used Adjustment technologies. These technologies include both power pre-allocation schemes that can be defeated based on known geographic environment distribution information, and dynamic power adjustments that can meet real-time user power allocation needs, and power adjustments made by users.
  • the dynamic range will be significantly higher than that of traditional CDMA systems (the "dynamic range” mentioned here is significantly increased, which is achieved by reducing the "minimum required power” index).
  • traditional CDMA can be called a "green” mobile phone because it can perform a certain range of power control to reduce transmit power
  • LAS-CDMA technology can further reduce the power of mobile phones and mobile phones due to more thorough and reasonable power adjustment.
  • the transmission power of the base station reduces the power consumption of the mobile phone and increases the standby time of the mobile phone, which will further reflect the "people-oriented, environment-oriented" characteristics of the technology.
  • the invention greatly reduces neighboring cell interference. Therefore, a simpler hard handover technique is used. Reduce interference to neighboring cells or sectors. It makes it possible for different cells to adopt different time slot allocation patterns. It can save the transmission power of the signal, can effectively overcome the effects of deep fading on the amplitude and phase of the signal, and can guarantee the advantages of applying a higher-dimensional modulation mode in a high-speed mobile environment. At this time, the performance of the system is less affected by the moving speed of the mobile station, that is, it is less affected by the fast fading caused by Doppler frequency shift, so it can effectively overcome the deep fading caused by high-speed movement on the signal amplitude and phase. Impact, while applying this method can guarantee the application of higher-dimensional modulation methods such as 8 PSK, 16PSK, 32PSK, 16QAM, 32QAM, 64QAM, 64 PSK in a high-speed mobile environment.
  • Figure 1 is the schematic diagram of the LAS code
  • Figure 1 is a TD-LAS frame structure diagram
  • FIG. 3 is a structural block diagram of a device transmitter of the present invention.
  • FIG. 4 is a structural block diagram of a device receiver of the present invention.
  • the TD-LAS system is proposed based on a new CDMA technology-LAS-CDMA. Because of this fundamental technical difference, the TD-LAS system has many technical characteristics that are different from traditional CDMA.
  • the TD-LAS system is based on the LAS-CDMA core technology and is a "all-IP" -oriented mobile communication system. Therefore, the specific implementation of the present invention is as follows:
  • the CDMA technology used in traditional CDMA mobile communication systems is based on long pseudo-random codes (PN) and short orthogonal codes (Wal sh or Golden sequences).
  • PN pseudo-random codes
  • Wal sh or Golden sequences short orthogonal codes
  • the present invention uses LAS codes as spread-spectrum multiple access codes; uses LA codes and LS codes for networking between cells; subframes of a wireless frame structure are composed of LA codes and LS codes; The uplink synchronization access pulse is formed based on the LS code; the downlink synchronization subframe is formed of the LA code and the LS code.
  • the invention is based on the LAS-CDMA technology.
  • the LAS-CDMA technology is based on the LAS code.
  • the LAS code is composed of a LA code and an LS code.
  • CDMA Code Division Mul t iple Access
  • the communication capacity and spectrum efficiency of a multi-user wireless communication system based on CDMA (Code Division Mul t iple Access) technology are very closely related to the relevant characteristics of the spread-spectrum multiple access code used, Related correlation characteristics include the auto-correlation and cross-correlation characteristics of spread spectrum multiple access codes.
  • the auto-correlation and cross-correlation characteristics of the LAS code form a unique "zero interference window", which is a feature that spread-spectrum multiple access codes used in other traditional CDMA communication systems do not have.
  • TD-LAS system relies on a new address code design theory
  • the "zero interference window" characteristic basically eliminates the interference existing in the traditional CDMA system and completely eliminates the "far-near effect". Therefore, power control no longer has its importance, making the TD-LAS system a noisy receiver. Limited system, thereby greatly improving system capacity and spectrum efficiency.
  • the construction principle and construction method of the address code of LAS-CDMA and traditional CDMA are completely different.
  • TD-LAS system networking technology uses a networking scheme in which frequency reuse is one, that is, different cells use the same frequency. In order to distinguish different cells and reduce neighboring cell interference, it is necessary to use code space for networking. In traditional CDMA, different offsets of long PN codes are used for network design between cells. In the TD-LAS system, LA codes and LS codes (including different intervals and polar combinations of LA codes, different sets of LS codes, and rotation transformation of LS codes) can be used for networking between cells. . At the same time, the combination of the excellent correlation characteristics of the LAS code and the source / error correction channel coding can effectively reduce the interference between neighboring cells, thereby further improving the system capacity and the spectral efficiency. The networking principles and networking methods of LAS-CDMA and traditional CDMA are completely different.
  • TD-LAS frame structure The design of the wireless frame structure greatly depends on the basic technology of the physical layer.
  • the frame structure of traditional CDMA system is designed based on PN. Code and Walsh code.
  • the design of the wireless frame structure of the TD-LAS system fully reflects the characteristics of the LAS code, and its unique subframe is composed of LA code and LS code.
  • Such a design can give full play to the advantages of the combination of LA code and LS code, and can effectively support large area coverage under the time division duplex (TDD) working mode, and can also rate the system's uplink and downlink services.
  • TDD time division duplex
  • the wireless transceiver is the basic component of the system.
  • the baseband filter is a key technology.
  • the baseband filter used is designed based on the characteristics of the PN code and Walsh code; it is based on supporting voice services and low-dimensional modulation methods such as BPSK,
  • the baseband shaping filters designed by QPSK / DQPSK and GMSK are difficult to support the high-speed data services of future mobile communication systems.
  • TD-LAS system a specially designed finite impulse response baseband shaping filter is adopted for the unique characteristics of the LA code and the LS code.
  • This baseband shaping filter has a linear phase, and has better amplitude-frequency response characteristics than existing baseband shaping filters in mobile communication systems, and has better robustness to sampling time errors.
  • digital baseband signal waveform distortion using low-dimensional modulation methods such as BPSK, QPSK / DQPSK, GMSK smaller, but also for digital using high-dimensional modulation methods such as 8 PSK, 16PSK, 32PS, 16QAM, 32QAM, 64QAM, 64 PSK
  • the baseband signal waveform distortion is small, which can support digital mobile communication systems using high-dimensional modulation methods, such as 8 PSK, 16PSK, 32PSK, 16QAM, 32QAM, 64QAM, 64 PSK, etc.
  • the interference between adjacent channels in China is small, and the interference to other communication systems is also small. It can improve the spectral efficiency and system capacity of mobile communication systems, especially high-speed mobile communication systems, so as to establish a large capacity and provide high data.
  • the foundation of wireless digital communication systems for transmission services is laid.
  • TPC channel coding In order to efficiently transmit high-speed data in a wireless environment, the turbo code channel coding technology is a key technology.
  • PCCC parallel concatenated convolutional code
  • SCCC serial concatenated convolutional code
  • the corresponding decoding algorithms are soft-in-soft-out iterative MAP decoding algorithm, LOG-MAP or simplified Algorithms such as MAX-LOG-MAP, S0VA, etc. are all two-way algorithms with a large amount of computation.
  • the corresponding decoder has a complicated structure, high cost, slow processing speed, and large delay.
  • TPC tri product code channel coding technology
  • a new iterative decoding algorithm can be adopted: an iterative decoding method of a concatenated block code based on subcode accompanying decoding.
  • This decoding algorithm is an iterative decoding method that can be used for concatenated block codes and their special form product codes.
  • Its subcode decoding is based on partial selection in the combination check matrix Adjoint decoding in the selected column.
  • the list decoding algorithm can effectively produce soft output values, so that iterative decoding of concatenated block codes and their special form product codes is feasible.
  • parameter 1 in the decoding method the design of the decoder can be a compromise between performance and decoding complexity.
  • the TPC turbo product code
  • the corresponding codec has a simple structure, low complexity, fast processing speed, and small delay, and can obtain higher channel coding gain for high coding efficiency and short frames.
  • TP-HARQ In the future, IP-oriented mobile communication systems place high requirements on the efficiency and reliability of wireless packet data transmission.
  • HARQ is a key technology.
  • Most existing 3G systems use the RCPT / HARQ technology based on the PCCC scheme to implement error control at the physical layer.
  • the implementation of type I system is relatively simple, but the system efficiency is obviously inferior to that of type II system under the same QoS.
  • the Chase combination method cannot provide effective system throughput at high channel error rates, and the use of the IR method to improve system performance in harsh channel environments must increase system complexity and Cost is the price.
  • the TD-LAS system uses a TP-ARQ technology based on TPC coding.
  • the system uses a type of TPC error correction with strong error correction capability and simple structure.
  • TPC can simultaneously correct random errors and burst errors in practical applications, it is particularly suitable for interference in complex channel environments.
  • the system can obtain a more flexible code rate by selecting subcodes reasonably and truncating them appropriately.
  • the code rate is greater than 2/3, the performance of the TPC scheme is better than the PCCC scheme, and the TPC is more suitable for a short frame structure.
  • the soft-in and soft-out iterative MAP decoding algorithm (or simplified algorithm) used by the PCCC scheme is a two-way algorithm with a large amount of calculations.
  • the corresponding decoder has a complicated structure, high cost, and low processing speed.
  • the TP-ARQ scheme uses a better TPC decoding algorithm-a TPC iterative decoding algorithm based on subcode adjoint decoding, that is, a linear block code decoding algorithm with reduced complexity is applied to the product Iterative decoding of codes.
  • the advantage is that it can obtain better decoding performance without increasing the complexity of the algorithm, and can support more types of subcodes.
  • the selection of this algorithm further enables the TP-ARQ system to obtain the highest possible coding gain and system efficiency with the lowest possible system complexity.
  • STSTD transmit diversity Transmit diversity technology can effectively improve the efficiency of the system and improve the performance of the system under fading channels.
  • TSTD, STTD, 0TD, STD and other transmit diversity technologies are used.
  • the first three are open-loop modes, while STD uses a half-open-loop mode, that is, the transmit diversity of the base station needs to select the downlink antenna according to the uplink data sent by the mobile station, and because it relies on continuous pilot signals to perform the channel Estimation and demodulation, so the base station also needs to provide downlink instructions to inform the mobile station which pilot channel should be used for demodulation.
  • the above-mentioned existing transmit diversity methods have the following disadvantages: For example, when an open-loop transmit diversity method is used, the improvement of the system's receiving performance is not ideal, the accuracy is not high enough, and it is very sensitive to the environment.
  • the open-loop transmit diversity method is more complicated to implement. Because it needs to rely on continuous pilot signals for channel estimation and demodulation, and then provides downlink instructions according to this, it is more complicated to implement and has a limited application range.
  • the TD-LAS system intends to use a new type of transmit diversity method-STSTD. This method can well improve the transmit diversity performance.
  • STSTD is characterized by: using prediction technology to adaptively select the transmitting antenna, that is, according to the symmetry and continuity of the forward and reverse channels of the TDD system, and use the fading coefficient of the reverse channel to estimate the fading coefficient of the forward channel, according to the estimated
  • the fading coefficient is determined by adaptively selecting the transmitting antenna at the transmitting end and adopting the Dedicated pilot channels are used for channel estimation and demodulation.
  • the prediction technology because the prediction technology is used, the downlink fading coefficient can be accurately estimated, while the traditional STD simply uses the reverse fading coefficient to select the forward transmission without any prediction, so this This method can select the antenna more accurately than STD. Because the dedicated pilot channel is used for demodulation, forward and reverse instruction instructions are no longer needed, transmission of control instructions is saved, and the performance that can be achieved with a closed-loop STD system can be achieved.
  • Uplink synchronization Synchronization
  • the CDMA system requires each user to maintain synchronization when arriving at the base station, so uplink synchronization is a key technology.
  • the traditional CDMA system especially the synchronous CDMA system (such as the implementation.
  • the TD-LAS system a unique uplink synchronization subframe is designed, in which the uplink synchronization access pulse is based on the LS code. It is precisely because of the LS code It has a unique symmetry characteristic, so the receiving end of the uplink synchronization channel is matched with a corresponding matched filter to perform a correlation operation to obtain a very good autocorrelation characteristic, that is, it has a high main peak and a secondary peak less than or equal to zero.
  • This autocorrelation characteristic can Very good resistance to fading, increasing the accuracy of reverse synchronization.
  • the spread-spectrum code LS code used in the TD-LAS system has a cross-correlation zero window characteristic. In this way, the system requires that the code sequences of all uplink users reach the base station at the same time. Therefore, a standard time is set at the uplink synchronization channel receiver of the base station, and the Set an uplink synchronization success threshold. When the difference between the time when the uplink synchronization pulse arrives at the base station and the standard time is less than the preset uplink synchronization success threshold, the uplink synchronization is considered successful; otherwise, it is considered unsuccessful and the uplink synchronization process Need to continue. Upstream bit synchronization and frame synchronization are performed simultaneously.
  • Downlink synchronization For mobile stations, the prerequisite for system access is to complete the downlink synchronization. In the traditional CDMA system, the downlink synchronization is achieved by sliding correlation of the PN code and searching all possible PN code phases to complete synchronization acquisition. In the TD-LAS system, a unique downlink is designed
  • the synchronization subframe is composed of a LA code and an LS code.
  • the LS + LA code group has excellent auto-correlation and cross-correlation characteristics (periodic correlation and aperiodic correlation), and can be directly used for synchronous acquisition. Using a matched filter that matches a specific channel (such as the synchronization channel in the lower row), the entire set of LS + LA code groups can be searched for cell search and target cell search.
  • power adjustment technologies can be used. These technologies include both power pre-allocation schemes that can be made based on known geographic environment distribution information, and dynamic power adjustments that can meet real-time user power allocation needs.
  • the dynamic range of the power adjustment will be significantly higher than that of the traditional CDMA system (the "dynamic range” mentioned here is significantly increased, which is accomplished by reducing the "minimum required power” index).
  • traditional CDMA can be called a "green” mobile phone because it can perform a certain range of power control to reduce transmit power
  • LAS-CDMA technology can further reduce the power of mobile phones and mobile phones due to more thorough and reasonable power adjustment.
  • the transmission power of the base station reduces the power consumption of the mobile phone and increases the standby time of the mobile phone, which will further reflect the "people-oriented, environment-oriented" characteristics of the technology Color.
  • each cell or sector sends a continuous pilot signal with the same spreading code (Walsh code) and different offset PN codes, and the MS contains the PN of each neighboring cell or sector Offset information, which is stored in different subsets (active subset, candidate subset, adjacent subset, and reserved subset), and will be updated as conditions update.
  • the MS communicates with all cells or sectors in the active subset.
  • the MS needs a complex Rake receiver to perform diversity combining of forward links.
  • the BS must provide a channel for the MS that maintains the communication, and provide a link to the MSC for the mobile station in the inter-cell handover state to perform diversity combining of reverse links.
  • Soft handover enables seamless handover.
  • each cell or sector sends a continuous pilot signal with the same LS code and different LA codes, and the MS contains LA code information of each neighboring cell or sector.
  • the MS only maintains communication with one cell or sector.
  • the MS will turn on another downlink synchronization receiver, poll the downlink synchronization signal strength of other cells or sectors, and calculate synchronization between different cells. Time deviation.
  • the MS After receiving the handover command from the network, the MS will immediately interrupt communication with the current cell or sector, and use the time offset measurement value to directly send uplink service information to the new cell or sector and establish a downlink communication link. Frequency signal for tracking and adjustment of uplink synchronization.
  • the MS will stop the communication of the uplink service, send an uplink synchronization pulse in the idle access slot, and re-establish uplink synchronization with the new cell. Hard handover is not seamless.
  • Dynamic codeword allocation In the traditional CDMA system, the network side using PN code and Walsh code Case. Due to the different transmission rates required for voice and data services (mostly short codes are used for voice and long codes are used for data), in the codeword allocation process, once the codeword on the trunk is assigned to the MS, the corresponding branch is Codewords will no longer be available.
  • the WDD system's FDD mode uses this dynamic 0VSF allocation strategy. Based on the design idea of interference white noise, the more random the allocation of the Walsh code by each cell or sector, the better.
  • TD-LAS a networking scheme combining LA codes and LS codes is used.
  • the TD-LAS system does not use multiple access codes with different lengths to meet the requirements of different transmission rates for voice and data services, but uses codewords with the same spreading length.
  • codewords with the same spreading length.
  • the method of split spreading is used. Because the size of the zero correlation window is different between different LS code groups, the more regular the LS code allocation in each cell or sector is, the better the code group with the larger zero correlation window is used to reduce interference to neighboring cells or sectors as much as possible. .
  • Dynamic channel allocation is divided into slow and fast dynamic channel allocation.
  • the CDMA2000 system does not use dynamic channel allocation technology, because it uses PN code offset to implement networking. It can only fixedly allocate a PN code offset to each cell during network planning.
  • the TDD mode of WCDMA system uses Dynamic (slow and fast) channel allocation techniques are introduced.
  • TD-LAS system also uses dynamic channel allocation technology.
  • the slow dynamic channel allocation is the same as the traditional CDMA system, so according to the uplink and downlink service load of different cells for a long time, different numbers of uplink and downlink time slots are allocated.
  • fast dynamic channel allocation because TD-LAS uses LS codes to distinguish users, the unique "zero-interference window" feature of LS codes makes the allocation of channel resources to mobile stations more flexible and complex; meanwhile, special LA codes combine The networking mode of the LS code makes it possible for different cells to use different time slot allocation patterns.
  • Two-channel channel estimation In order to compensate the signal fading and distortion of the mobile system in the communication channel, channel estimation technology must be used. In a fading channel, the accuracy of the channel estimation directly affects the performance of the system. In traditional CDMA systems, continuous pilot channel estimation methods and dedicated pilots are used. Channel estimation method. The channel estimation method using continuous pilots needs to occupy a dedicated channel, so the transmit power of the transmitter needs to be increased. Therefore, continuous pilots are only used for downlink communications (from base stations to mobile stations) in synchronous CDMA systems, while dedicated pilots The frequency channel estimation method is greatly affected by the moving speed of the mobile station, and the system performance will rapidly deteriorate in a high-speed mobile environment.
  • the proposed dual channel channel estimation method can save the transmission power of the signal, can effectively overcome the effects of deep fading on the signal amplitude and phase, and can guarantee high-speed Advantages of applying higher-dimensional modulation in mobile environments.
  • the performance of the system is less affected by the moving speed of the mobile station, that is, it is less affected by the fast fading caused by Doppler frequency shift, so it can effectively overcome the deep fading caused by high-speed movement on the signal amplitude and phase. Impact, while applying this method can guarantee the application of higher-dimensional modulation methods such as 8 PSK, 16PSK, 32PS, 16QAM, 32QAM, 64QAM, 64 PSK in a high-speed mobile environment.
  • the transmitter includes at least a spreading device using a LAS code as a spread spectrum multiple access code; and the receiver includes at least a spreading device based on the LAS code.
  • Frequency multiple access code despreading device the transmitter may further include a radio frame framing device, a finite impulse response baseband filter, a TPC encoder, a modulator, a CRC checker, a HARQ controller, a synchronization device, STSTD transmission diversity device and power adjustment device;
  • the receiver may further include a radio frame de-frame device, a matched filter, a TPC iterative decoder based on a subcode adjoint type, a demodulator, a CRC checker, and a synchronization device And STSTD receiving diversity device; wherein the subframe of the wireless frame structure is composed of LA code and LS code; the information sent by the source can be checked by the CRC checker, TPC encoder coding, modulator modulation, and LAS code is used for expansion -Frequency multiple access code spreading device spreading, wireless frame framing device framing, finite impulse response baseband filter filtering, STSTD transmit diversity device transmit diversity, power adjustment device power adjustment,
  • the present invention provides a device for constructing a TD-LAS system. It is a mobile communication system based on LAS-CDMA core technology and oriented to "all IP".
  • the auto-correlation and cross-correlation characteristics of LAS codes form a unique "zero interference""Window", which is not a feature of spread-spectrum multiple access codes used in other traditional CDMA communication systems.
  • the invention greatly reduces interference between adjacent cells, improves system capacity and spectrum efficiency; can effectively support large area coverage in a time division duplex (TDD) working mode, and can also provide system uplink and downlink services.
  • TDD time division duplex
  • the corresponding codec structure of the present invention is simple, has low complexity, fast processing speed, and small time delay, and can obtain higher channel coding gain for high coding efficiency and short frames. Corrects random errors and burst errors, so it is especially suitable for interfering with complex channel environments. It simplifies the coding and decoding equipment and speeds up the decoding processing speed, thus ensuring the same performance of the system. This reduces the complexity of system implementation. Get better decoding performance without increasing the complexity of the algorithm, and can support more types of subcodes. Further, the TP-ARQ system can obtain the highest coding gain and system efficiency with the lowest system complexity possible.
  • the invention can also improve the transmit diversity performance well, can well resist fading, and increase the accuracy of reverse synchronization.
  • the invention shortens the synchronization acquisition time and improves the performance of cell search and target cell search.
  • the present invention does not have the "far-near effect" in the conventional CDMA system. Therefore, power adjustment technologies can be used. These technologies include both power pre-allocation schemes that can be made based on known geographic environment distribution information, and dynamic power adjustments that can meet real-time user power allocation needs.
  • the dynamic range of the power adjustment will be significantly higher than that of the traditional CDMA system (the "dynamic range” mentioned here is significantly increased, which is accomplished by reducing the "minimum required power” index).
  • traditional CDMA can be called a "green” mobile phone because it can perform a certain range of power control to reduce the transmission power
  • LAS-CDMA technology can further reduce the power of mobile phones and mobile phones due to more thorough and reasonable power adjustment.
  • the transmission power of the base station reduces the power consumption of the mobile phone and increases the standby time of the mobile phone, which will further reflect the "people-oriented, environment-oriented" characteristics of the technology.
  • the invention greatly reduces neighboring cell interference. Therefore, a simpler hard handover technique is used. Reduce interference to neighboring cells or sectors. It makes it possible for different cells to adopt different time slot allocation patterns. It can save the transmission power of the signal, can effectively overcome the effects of deep fading on the signal amplitude and phase, and can guarantee the application of higher-dimensional modulation methods in high-speed mobile environments. At this time, the performance of the system is less affected by the moving speed of the mobile station, that is, it is less affected by the fast fading caused by Doppler frequency shift, so it can effectively overcome the deep fading caused by high-speed movement on the signal amplitude and phase. Impact, while applying this method can guarantee the application of 8 PSK, 16PSK, 32PSK, QAM, 32QAM, 64QAM, 64 PSK and other higher-dimensional modulation methods

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  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Mobile Radio Communication Systems (AREA)

Abstract

L'invention concerne un procédé de construction d'un système TD-LAS, consistant à: utiliser le code LAS comme code d'adresse multiple à spectre étalé; utiliser le code LA et le code LS afin d'établir la liaison dans des cellules, la construction de trame radio étant comprise dans le code LA et le code LS; s'inspirer du code LS pour l'impulsion d'accès de la synchronisation à liaison ascendante; faire en sorte que la sous trame de la synchronisation à liaison descendante soit constituée du code LA et du code LS. L'invention concerne également un dispositif de construction d'un système TD-LAS formé d'un émetteur et d'un récepteur, ledit émetteur comprenant au moins des moyens de spectre étalé, utilisant le code LAS comme code d'adresse multiple à spectre étalé, ledit récepteur comprenant au moins des moyens de désétalement utilisant le code LAS comme code d'adresse multiple à spectre étalé. L'information provenant d'une source est étalée au moins par des moyens d'étalement et envoyée vers le canal, les moyens d'étalement utilisant le code LAS comme code d'adresse multiple à spectre étalé. L'information reçue par un collecteur a été au moins désétalée par des moyens de désétalement, le code multiple à spectre étalé s'inspirant du code LAS.
PCT/CN2002/000143 2002-03-11 2002-03-11 Procede et dispositif de construction du systeme td-las WO2003077458A1 (fr)

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CN02827048.7A CN1613221A (zh) 2002-03-11 2002-03-11 一种构建td－las系统的方法及装置
AU2002238361A AU2002238361A1 (en) 2002-03-11 2002-03-11 Method and device for constructing td-las systems

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CN101692663B (zh) * 2009-08-26 2012-05-23 北京交通大学 无线通信系统的符号同步方法

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WO2001095644A1 (fr) * 2000-06-05 2001-12-13 Linkair Communications, Inc. Procede pour l'interface aerienne de façon a supporter un debit de donnees variable
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