WO2003007520A1 - Procede et systeme de synchronisation rapide de liaison montante et recepteur pour voie d'acces d'une station de base - Google Patents

Procede et systeme de synchronisation rapide de liaison montante et recepteur pour voie d'acces d'une station de base Download PDF

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Publication number
WO2003007520A1
WO2003007520A1 PCT/CN2001/001173 CN0101173W WO03007520A1 WO 2003007520 A1 WO2003007520 A1 WO 2003007520A1 CN 0101173 W CN0101173 W CN 0101173W WO 03007520 A1 WO03007520 A1 WO 03007520A1
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WO
WIPO (PCT)
Prior art keywords
access
time
mobile station
base station
signal
Prior art date
Application number
PCT/CN2001/001173
Other languages
English (en)
Chinese (zh)
Inventor
Li Fang
Yuan Zhang
Rakesh Tamrakar
Original Assignee
Linkair Communications, Inc.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Linkair Communications, Inc. filed Critical Linkair Communications, Inc.
Priority to PCT/CN2001/001173 priority Critical patent/WO2003007520A1/fr
Priority to CN01815249.XA priority patent/CN1211966C/zh
Publication of WO2003007520A1 publication Critical patent/WO2003007520A1/fr

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Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W56/00—Synchronisation arrangements
    • H04W56/004—Synchronisation arrangements compensating for timing error of reception due to propagation delay
    • H04W56/0045—Synchronisation arrangements compensating for timing error of reception due to propagation delay compensating for timing error by altering transmission time
    • 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
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04J—MULTIPLEX COMMUNICATION
    • H04J13/00—Code division multiplex systems
    • H04J13/16—Code allocation
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04J—MULTIPLEX COMMUNICATION
    • H04J13/00—Code division multiplex systems
    • H04J13/0007—Code type
    • H04J13/004—Orthogonal

Definitions

  • the present invention relates to a wireless communication system, and more particularly, to a synchronous code division multiple access (CDMA) communication system.
  • CDMA synchronous code division multiple access
  • wireless communication has become one of the most active aspects in the communication field. Due to its unique advantages such as large capacity, soft capacity, soft handover, high voice quality and low transmit power, and strong anti-interference and confidentiality, It has stood out, developed rapidly, and has become the technology of choice for third-generation cellular systems.
  • CDMA is a modulation and multiple access technology based on spread-spectrum communications.
  • the signals used by different users to transmit information are distinguished by their own different coding sequences. Since the CDMA system uses different code patterns to distinguish channels, these channels are both in the frequency and time domains. They overlap each other, or they all occupy the same frequency band and time. Therefore, the performance of a CDMA system depends to a large extent on the characteristics of the code pattern, that is, the degree of mutual interference between multiple channels is important for determining the channel capacity of a CDMA system. And characteristics will be an important factor.
  • FIG. 1 shows a schematic diagram of a cellular mobile communication system.
  • a hexagon is a cell, and wireless communication is performed between a base station and a mobile station in the cell.
  • Mobile stations each mobile station uses an independent channel, that is, a different spreading address code, and performs wireless communication with the base station at the same time.
  • the downlink from the base station to the mobile station downl ink
  • the mobile station to the base station is called the uplink (upl ink).
  • the channels are distinguished from each other by the different codes used, so the correlation between such codes is very important. That is, the independence between such channels if and only if assigned to The codes of the respective channels are not correlated with each other and are guaranteed.
  • receivers use a given signal to recover their associated signals, these receivers should not be affected by channels that use other encodings.
  • the spreading code used is generated by a pseudo-noise code sequence Walsh code having the smallest cross-correlation value and the largest auto-correlation value.
  • IS95 The system is an asynchronous CDMA system. Its uplink channel, that is, the signals sent by all mobile stations to the base station are transmitted asynchronously, because the pseudo noise sequences from different mobile stations cannot be synchronized, and the pseudo noise code sequences of different mobile stations cannot be positive to each other. Therefore, spread-spectrum signals in the same frequency band and at the same time will form great interference with each other, that is, multiple-access interference. This interference not only greatly reduces the channel capacity, but also increases the complexity of power control.
  • the synchronization of the downlink is easy to achieve, because all signals are sent from a single base station.
  • the realization of the synchronization of the uplink is much more difficult.
  • the distance between each mobile station and the base station is different.
  • the signal delay is also different, and the mobile station does not know the distance between itself and the base station, and cannot adjust the time to send the signal, which causes the mobile station to send the signal to the base station out of synchronization. It becomes more difficult to establish.
  • a first object of the present invention is to provide a method for quickly synchronizing an uplink in a synchronous code division multiple access communication system, so as to solve the above-mentioned problems and defects in the prior art.
  • a second object of the present invention is to provide a system for quickly synchronizing an uplink in a synchronous code division multiple access communication system.
  • a third object of the present invention is to provide a base station access channel receiver used in a synchronous code division multiple access communication system.
  • the present invention provides a method for The method for performing uplink synchronization quickly includes the following steps:
  • the mobile station selects an idle access slot from a plurality of access slots into which the access channel included in the uplink is divided according to the information sent by the base station;
  • the base station detects the access code, and determines delay adjustment information of the mobile station
  • the base station sends the delay adjustment information to the mobile station
  • the mobile station adjusts its transmission time according to the received delay adjustment information, so that the subsequently transmitted signals reach the base station at the standard access time.
  • the present invention provides a system for fast synchronization of an uplink in a synchronous code division multiple access communication system.
  • the synchronous code division multiple access communication system includes at least one mobile station and at least one base station.
  • the at least one mobile station includes:
  • the at least one base station includes:
  • the at least one mobile station further includes:
  • the present invention provides a base station access channel receiver used in a synchronous code division multiple access communication system, which is characterized by including:
  • a matched filter configured to perform a correlation operation between a low-pass filtered signal and a pre-stored access code sequence
  • a maximum value search circuit configured to determine an output signal of the matched filter according to a related parameter Threshold value
  • a limiter configured to output a valid signal at the threshold value
  • a sliding correlator configured to calculate, according to the valid signal, a time elapsed when the access code arrives at the base station from the mobile station;
  • An offset calculation module configured to compare the elapsed time with a standard time, and calculate a time offset
  • the method or system for performing fast synchronization on an uplink in a synchronous code division multiple access communication system of the present invention it is possible to quickly and simultaneously realize synchronous reception between uplink signals of multiple mobile stations, thereby reducing the number of channels between channels. Interference, increase the channel bulk density of the system, and because of the unique access code and special matched filter structure, the synchronization accuracy is high, the number of adjustments is small, and the uplink synchronization can be established quickly and efficiently. Easy to implement.
  • the arrival time of the mobile station signal is calculated from the signal energy of each mobile station user, and it is compared with the standard time, and then the adjusted time
  • the delay information is placed in the downlink and sent to the mobile station.
  • the mobile station After receiving the delay adjustment information of the base station, the mobile station adjusts its transmission time so that the signal reaching the base station finally meets the standard access time.
  • FIG. 1 is a schematic structural diagram of a cellular mobile communication system
  • FIG. 2 is a flowchart of a method for performing fast synchronization on an uplink in a synchronous code division multiple access communication system according to the present invention
  • FIG. 3 is a detailed flowchart of the base station detecting the access code and determining the delay adjustment information;
  • FIG. 4 is the uplink from the mobile station to the base station applied in the present invention;
  • FIG. 5 shows a characteristic diagram after an access code passes a matched filter for storing the same access code
  • Figure 6 shows the characteristic after the access code passes the matched filter used to store different access codes.
  • Fig. 7 is a schematic structural diagram of a base station access channel receiver used in a system for fast synchronization of uplinks in a synchronous code division multiple access communication system according to the present invention. Best practice of the invention:
  • Fig. 2 is a flowchart of a method for fast synchronization of uplinks in a synchronous code division multiple access communication system according to the present invention.
  • the mobile station user After the mobile station is powered on, the mobile station user first receives the information sent by the base station from the downlink, performs frequency correction and frame synchronization and bit synchronization with the system, and obtains the information of the available access channel microphones.
  • the mobile station step 201 According to the information about the available access channel time slots, an idle access time is selected from a plurality of access time slots into which the access channel included in the uplink is divided. Then, in step 202, the mobile station sends a fixed access code at a certain time within the selected idle time slot. The specific structure of the access channel will be described later with reference to FIG. 4.
  • step 203 the base station detects the access code sent by the mobile station, and determines the delay adjustment information of the mobile station.
  • step 204 the base station sends the delay adjustment information to the mobile station.
  • step 205 the mobile station adjusts its transmission time according to the received delay adjustment information, so that the subsequently transmitted signals reach the base station at the standard access time.
  • FIG. 3 A detailed flowchart of the station detecting the access code and determining the delay adjustment information. The process shown in FIG. 3 constitutes step 203 in FIG. 2.
  • step 2031 the received signal is demodulated, low-pass filtered, matched filtered, and correlated.
  • step 2032 a maximum value search circuit and related parameters are used to determine a threshold value of the signal.
  • step 2033 a valid signal is output by the limiter by comparing with the threshold value.
  • step 2034 a sliding correlator is used to calculate the time it takes for the access code to reach the base station from the mobile station.
  • step 2035 the elapsed time is compared with a standard time, and a time offset is calculated as the delay adjustment information.
  • FIG. 4 is a schematic structural diagram of an uplink incoming channel from a mobile station to a base station applied in the present invention.
  • the access channel is divided into M time slots.
  • each mobile station is allocated a time slot to perform access, and finally the time when the user signal arrives at the base station is at this time.
  • Gap In a standard position, the signals of each mobile station in the uplink reach the base station synchronously.
  • the mobile station In order to ensure that the mobile station accesses the standard position, the mobile station must send an N-bit codeword (occupies NT C ) in a time slot. Since one time slot allocated to the access channel is KTc Therefore, the starting position of the codeword sent by the mobile station ranges from 0 to (KN) Tc. T c other than the N-bit transmission codeword is not transmitted signal.
  • the access code used in the present invention is a unique spreading code.
  • the access code is composed of three parts.
  • the length of the access code is N bits, so the first N / 3 bits are determined as sequence 1, and the last N / 3
  • the bit is sequence 2, the middle complements N / 3 bit 0, and the sequence 1 and sequence 2 have orthogonal complementary characteristics.
  • a fixed set of access codes can be used for access, but different time slots can be selected.
  • a mobile station Each time a mobile station accesses, it sends a fixed access code in one of the M slots allocated to the access channel (KT C ). Because the user does not know his own signal when he starts to access Whether it is the standard position for access after arriving at the base station, so the transmission time (the transmission time of the first bit of the N-bit codeword) is set to a fixed value S.
  • the base station access channel receiver calculates the deviation of the signal sent by the mobile station once in each time slot (KT C ) unit.
  • the access channel receiver of the base station calculates the arrival time of the mobile station signal by receiving the signal energy of each mobile station user in different access time slots, and compares it with the standard time to calculate the user signal arrival time and The gap between the standard access locations is then transmitted to the mobile station via the downlink to transmit the time delay adjustment information.
  • the mobile station user's controller adjusts the user's next access codeword transmission time until The time when the user access signal arrives at the base station is standard time.
  • Figure 5 shows the characteristic diagram after the access code passes the matched filter for storing the same access code. It can be seen that the sub-peaks are all less than or equal to 0, and the main peak is large.
  • Figure 6 shows the characteristic diagram after the access code passes the matched filter for storing different access codes. It can be seen that its cross-correlation peak is very small compared to the main peak of the autocorrelation.
  • At least one mobile station included in a synchronous code division multiple access communication system includes:
  • a device for selecting an idle access slot in the access slot It is used to divide a plurality of access channels included in an uplink based on information transmitted from a base station.
  • At least one base station included in a synchronous code division multiple access communication system includes:
  • the at least one mobile station further includes: means for reaching the base station at a standard access time.
  • the foregoing apparatus for detecting the access code and determining delay adjustment information of a mobile station includes:
  • a matched filter configured to perform a correlation operation between a low-pass filtered signal and a pre-stored access code sequence
  • a maximum value search circuit configured to determine a threshold value of an output signal of a matched filter according to related parameters
  • the limiter outputs a valid signal according to a threshold value
  • a sliding correlator for calculating the elapsed time from the mobile station to the base station according to the effective signal
  • the offset calculation module is configured to compare the elapsed time with the standard time, and calculate a time offset, where the time offset is delay adjustment information.
  • the above-mentioned components included in the base station may be set in a base station access channel receiver.
  • Figure 7 is a schematic diagram showing the structure of such an access channel, the access channel receiver is used for fast synchronization of the uplink of the synchronous code division multiple access communication system.
  • reference numeral 601 represents a demodulator
  • 604 represents a low-pass filter
  • 607 represents a matched filter
  • 608 represents a limiter
  • 609 represents a maximum search circuit
  • 610 represents a sliding correlator
  • 611 represents a time offset. Calculation module.
  • the modulated signal is:
  • the I signal 602 is:
  • the Q signal 603 of the incoming signal after the demodulator 601 is:
  • the filter After passing the low-pass filter 604, the high-frequency signal is filtered.
  • the two signals after the low-pass filter are sent to a special matched filter 607.
  • the filter stores the access code. Sequence, the output of the matched filter cancels all positive sub-peaks of the codeword autocorrelation, so that the sub-peaks of the autocorrelation are zero or negative.
  • the large value search module 609 finds the largest value from the output signal of the matched filter 607, and uses the product of the value and a parameter as the threshold value of the limiter 608 at the back.
  • the output signal of the limiter 608 is sent to the next-stage sliding correlator (length L) 610.
  • the purpose is to find the position of the largest L adjacent values from the 2K values. That is, to find the last one from the 2K values.
  • the position of the maximum value (if there are two or more equal maximum values in the 2K value, the last position is taken), that is, the time when the user arrives at the base station.
  • the calculated time when the user signal arrives at the base station is compared with the standard position, the offset is calculated in the time offset calculation module 611, and a delay control command DCC (Delay Control Command) command is generated.
  • DCC Delay Control Command
  • the delay control instruction (or delay adjustment information) is transmitted to the mobile station in the downlink.
  • the mobile station user After receiving the information of the base station, the mobile station user adjusts its transmission time so that the signal reaching the base station finally meets the standard access time.
  • the deviation between the value output from the sliding correlator and the standard position is within the allowable range, it indicates that the access is successful. If a "1" signal is successfully output, DCC will output a special command to inform the user that the access is successful; if not, a "0" signal will be output, and DCC will be a command.
  • the base station wants to send a special DCC command to the user in the downlink, and the user sends the access pulse again. Access.
  • the above description can clearly show that because the access channel is used in the uplink and the access channel is divided into different time slots, more mobile stations can access the system at the same time, and the rapid establishment of the uplink is guaranteed.
  • the combination of access code and matched filter is used to ensure the accuracy of calculating the delay deviation of the signal sent by the mobile station and speed up the uplink synchronization establishment process.

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

Abstract

L'invention porte sur un procédé de synchronisation rapide d'une liaison montante dans un système de communication à accès multiple par répartition en code de synchronisation AMRCS, comprenant les étapes suivantes: (1) une station mobile sélectionne un créneau temporel d'accès au repos à partir d'une pluralité de créneaux temporels d'accès dans une voie d'accès comprenant une liaison montante à diviser, conformément à l'information de transmission de la station de base; (2) la station mobile transmet un code d'accès au point temporel du créneau d'accès au repos; (3) la station de base détecte ledit code d'accès et détermine une information de réglage de temporisation pour ladite station mobile; (4) la station de base transmet l'information de réglage de temporisation à la station mobile; (5) la station mobile règle la durée de transmission selon l'information de réglage de temporisation reçue, ce qui permet à l'information de transmission d'arriver à la station de base au moment d'accès standard.
PCT/CN2001/001173 2001-07-13 2001-07-13 Procede et systeme de synchronisation rapide de liaison montante et recepteur pour voie d'acces d'une station de base WO2003007520A1 (fr)

Priority Applications (2)

Application Number Priority Date Filing Date Title
PCT/CN2001/001173 WO2003007520A1 (fr) 2001-07-13 2001-07-13 Procede et systeme de synchronisation rapide de liaison montante et recepteur pour voie d'acces d'une station de base
CN01815249.XA CN1211966C (zh) 2001-07-13 2001-07-13 上行链路快速同步方法和系统

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/CN2001/001173 WO2003007520A1 (fr) 2001-07-13 2001-07-13 Procede et systeme de synchronisation rapide de liaison montante et recepteur pour voie d'acces d'une station de base

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Cited By (1)

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WO2007003071A1 (fr) * 2005-07-06 2007-01-11 Zte Corporation Procédé d’établissement de synchronisation de liaison ascendante reposant sur la technologie de transmission unifiée et matrice de transmission idoine

Families Citing this family (5)

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Publication number Priority date Publication date Assignee Title
CN1324824C (zh) * 2004-11-19 2007-07-04 中兴通讯股份有限公司 多时隙通信系统中终端同步控制命令的映射方法
CN101185270B (zh) * 2005-11-16 2010-10-13 中兴通讯股份有限公司 移动通信系统中的上行同步方法
US8682369B2 (en) 2009-06-22 2014-03-25 Alcatel Lucent Method and device for implementing uplink synchronization
CN105409271B (zh) * 2013-12-04 2019-07-09 华为技术有限公司 管理帧的发送处理方法及系统
CN109428614B (zh) * 2017-08-30 2020-04-28 华为技术有限公司 一种动态时间调整方法、装置和系统

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CN1182990A (zh) * 1997-10-05 1998-05-27 北京信威通信技术有限公司 同步码分多址通信链路的建立和保持方法
WO1999066586A2 (fr) * 1998-06-13 1999-12-23 Samsung Electronics Co., Ltd. Dispositif et procede permettant de commander l'acces a un canal par reservation d'un creneau temporel d'acces dans un systeme de communication mobile
CN1241877A (zh) * 1998-07-14 2000-01-19 三星电子株式会社 通信系统中分组业务信道初始化的方法

Patent Citations (3)

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Publication number Priority date Publication date Assignee Title
CN1182990A (zh) * 1997-10-05 1998-05-27 北京信威通信技术有限公司 同步码分多址通信链路的建立和保持方法
WO1999066586A2 (fr) * 1998-06-13 1999-12-23 Samsung Electronics Co., Ltd. Dispositif et procede permettant de commander l'acces a un canal par reservation d'un creneau temporel d'acces dans un systeme de communication mobile
CN1241877A (zh) * 1998-07-14 2000-01-19 三星电子株式会社 通信系统中分组业务信道初始化的方法

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2007003071A1 (fr) * 2005-07-06 2007-01-11 Zte Corporation Procédé d’établissement de synchronisation de liaison ascendante reposant sur la technologie de transmission unifiée et matrice de transmission idoine
US8300574B2 (en) 2005-07-06 2012-10-30 Zte Corporation Method of uplink synchronization establishment based on the united transmission technology

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CN1452821A (zh) 2003-10-29
CN1211966C (zh) 2005-07-20

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