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WO2008067346A2 - Systèmes et procédés de synchronisation rapide d'interface hertzienne sens montant - Google Patents

Systèmes et procédés de synchronisation rapide d'interface hertzienne sens montant Download PDF

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Publication number
WO2008067346A2
WO2008067346A2 PCT/US2007/085697 US2007085697W WO2008067346A2 WO 2008067346 A2 WO2008067346 A2 WO 2008067346A2 US 2007085697 W US2007085697 W US 2007085697W WO 2008067346 A2 WO2008067346 A2 WO 2008067346A2
Authority
WO
WIPO (PCT)
Prior art keywords
mobile device
determining
sub
base station
carriers
Prior art date
Legal status (The legal status 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 status listed.)
Ceased
Application number
PCT/US2007/085697
Other languages
English (en)
Other versions
WO2008067346A3 (fr
Inventor
Xuan Li
Manyuan Shen
Guanbin Xing
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Adaptix Inc
Original Assignee
Adaptix 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
Priority claimed from CNA2006101608429A external-priority patent/CN101192881A/zh
Application filed by Adaptix Inc filed Critical Adaptix Inc
Publication of WO2008067346A2 publication Critical patent/WO2008067346A2/fr
Publication of WO2008067346A3 publication Critical patent/WO2008067346A3/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L27/00—Modulated-carrier systems
    • H04L27/32—Carrier systems characterised by combinations of two or more of the types covered by groups H04L27/02, H04L27/10, H04L27/18 or H04L27/26
    • H04L27/34—Amplitude- and phase-modulated carrier systems, e.g. quadrature-amplitude modulated carrier systems
    • H04L27/38—Demodulator circuits; Receiver circuits
    • H04L27/3845—Demodulator circuits; Receiver circuits using non - coherent demodulation, i.e. not using a phase synchronous carrier
    • H04L27/3854—Demodulator circuits; Receiver circuits using non - coherent demodulation, i.e. not using a phase synchronous carrier using a non - coherent carrier, including systems with baseband correction for phase or frequency offset
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L27/00—Modulated-carrier systems
    • H04L27/26—Systems using multi-frequency codes
    • H04L27/2601—Multicarrier modulation systems
    • H04L27/2647—Arrangements specific to the receiver only
    • H04L27/2655—Synchronisation arrangements
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L27/00—Modulated-carrier systems
    • H04L27/26—Systems using multi-frequency codes
    • H04L27/2601—Multicarrier modulation systems
    • H04L27/2647—Arrangements specific to the receiver only
    • H04L27/2655—Synchronisation arrangements
    • H04L27/2668—Details of algorithms
    • H04L27/2673—Details of algorithms characterised by synchronisation parameters
    • H04L27/2675—Pilot or known symbols
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L5/00—Arrangements affording multiple use of the transmission path
    • H04L5/02—Channels characterised by the type of signal
    • H04L5/023—Multiplexing of multicarrier modulation signals, e.g. multi-user orthogonal frequency division multiple access [OFDMA]

Definitions

  • This invention relates to air interface communication systems synchronization between base stations and mobile devices and more particularly to rapid uplink synchronization based on signals sent from the mobile devices.
  • signals transferred from a plurality of mobile devices arrive at the base station with different propagation delays and different power. Large propagation delay and power difference often result in significant loss of signal at the base station.
  • One method for the base station to control the propagation delays and power levels of the signal from mobile devices is to have each mobile device send a predetermined pseudo random code identifying itself on a defined ranging time slot or channel. These codes, or ranging signals are used by the base station (which could include any suitable distant end transmission point) to determine the time delay and transmission power level of the mobile device.
  • the base station Since the base station does not know which code is being sent by the mobile device, the base station must isolate the sub-channel codes for each mobile device.
  • One method of isolating the code from a mobile device is to match the incoming signal against a known signal in order to determine which code is being sent.
  • the solution to the problem becomes a two- dimensional calculation, i.e., first the system must check to see if the signal contains a known code at a first time (first phase). If not, then the system must repeat the process for successive time slices (phases) to see if a particular code is being received. This is time consuming and requires high processor resources. Besides, the channel phase ambiguities acting on ranging channel will significantly deteriorate the measurement precise of propagation delays.
  • a two-dimensional (2D) search problem is reduced to two one- dimensional (ID) search problems, which can generally be performed in less time.
  • OFDMA Orthogonal Frequency Division Multiple Access
  • OFDM Orthogonal Frequency Division Multiplexing
  • Power levels for each ranging code can be calculated by correlating the differential received ranging sub-carriers with local predetermined differential ranging codes. All the ranging codes with power meeting a predetermined threshold are selected as the ranging codes transmitted from the mobile devices. Time delay measurement is then performed only for the selected ranging codes. Since in most cases the selected ranging codes belong to a subset of the total ranging codes, the computing complexity may be reduced.
  • FIGURE 1 illustrates one embodiment of a flow chart for obtaining uplink synchronization for air interface communication between a base station and a mobile device
  • FIGURE 2 shows a typical air interface system in which the concepts of the invention can be practiced.
  • FIGURE 1 illustrates one embodiment of flow chart 10 for obtaining uplink synchronization for air interface communication (23 FIGURE 2) between a base station , such as transmission point 201, shown in FIGURE 2, and a mobile device, such as device 21-1 shown in FIGURE 2.
  • the algorithm shown in FIGURE 1 can be run, for example, by processor 241 in conjunction with memory 242 operating in base station 24 which can be co-located with the actual point of transmission, or can be remote there from.
  • Process 101 extracts the ranging sub-carriers from the signal received from the mobile device from time to time.
  • the ranging sub-carriers are separated from the other data, such as the payload data, etc.
  • Each ranging channel is composed of multiple sub-carriers.
  • ranging sub- carriers may be specified.
  • the concepts discussed herein are particularly well-suited for OFDMA as well as OFDM systems.
  • a mobile device selects a pseudo-random code and transmits that code on all of the ranging sub-carriers.
  • the pseudo-random code identifies the mobile device, and the base station then determines, as will be discussed below, the average power level of each received random code in order to determine whether the mobile device which transmitted that code should adjust its transmission power.
  • Process 102 then differentially multiplies the adjacent ranging sub- carriers.
  • An approximation may be made that channels of adjacent sub-carriers are coherent, in the sense that phase characteristics will be approximately same between adjacent sub-carriers. This approximation is useful if sub-carrier spacing is smaller than the channel coherent bandwidth.
  • Channel phase rotation on each sub-carrier may then be removed by multiplying a specific sub-carrier with the conjugation of an adjacent sub- carrier.
  • Process 103 multiplies differential ranging sub-carriers with local replicas of the possible differential ranging codes, which maybe pre-calculated and stored in memory 242 shown in FIGURE 2, and then sums the multiplication results. This produces a correlation between the possible ranging codes and the ranging code transmitted by the mobile device. The correlation value of the ranging code transmitted by the mobile device will be highest value. In this manner, the correlation values can be used by base station 24, as will be discussed below, to isolate ranging codes for each mobile device.
  • Process 104 calculates the power of the correlation values for the convenience of threshold comparison in a following process.
  • Process 105 determines which ranging codes are transmitted by mobile devices. All of the ranging codes with power exceeding the predetermined threshold will be selected as the transmitted ranging codes. If no acceptable power level is found, the mobile device can be told to increase its power and transmit another ranging code in subsequence time frame.
  • Process 106 compares the power levels of the selected ranging codes with target power levels and thus determines the power adjustment value for that mobile device in subsequent transmissions.
  • Process 107 calculates time delay using several methods, such as, for example, phase detection, inverse FFT or sine wave correlation. This time delay corresponds to the round trip delay between base station and mobile device, and the mobile device can use this value to adjust its transmission time in subsequent frames.
  • Transmitted ranging codes may be shown as:
  • Received ranging codes in frequency domain is:
  • XXk,l) X t ⁇ k,l)-H ⁇ k,l)- e J N
  • H(k,l) is the complex channel transfer function of the k-th sub-carrier of the l-th transmitted ranging sequence
  • r(/) is propagation delay corresponding to the l-th ranging sequence
  • N is the sub-carrier number.
  • IFFT Inverse Fast Fourier Transform
  • Transmit time delay ⁇ may be obtained based on the first path of the channel impulse response.
  • this method requires an IFFT operation, which may be time consuming and resource intensive.

Landscapes

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

Abstract

L'invention concerne un procédé de synchronisation sens montant rapide qui consiste à réduire un problème de recherche bidimensionnel en deux problèmes de recherche d'identité, qui peuvent généralement être résolus plus rapidement. Un dispositif mobile envoie un code de télémétrie sur plusieurs sous-porteuses. En supposant que les sous-porteuses adjacentes auront des caractéristiques de canal sensiblement équivalentes, il est possible de supprimer l'ambiguïté de phase par combinaison différentielle de paires de sous-porteuses adjacentes. Une fois l'ambiguïté de phase supprimée, il est possible de déterminer relativement rapidement le code, la synchronisation et le niveau de puissance. Dans un mode de réalisation, le procédé consiste à comparer les valeurs de corrélations entre les signaux reçus et les codes possibles à un seuil.
PCT/US2007/085697 2006-11-30 2007-11-28 Systèmes et procédés de synchronisation rapide d'interface hertzienne sens montant Ceased WO2008067346A2 (fr)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
CNA2006101608429A CN101192881A (zh) 2006-11-30 2006-11-30 用于快速上行链路空中接口同步的系统和方法
CN200610160842.9 2006-11-30
US11/651,239 2007-01-09
US11/651,239 US8259777B2 (en) 2006-11-30 2007-01-09 Systems and methods for rapid uplink air interface synchronization

Publications (2)

Publication Number Publication Date
WO2008067346A2 true WO2008067346A2 (fr) 2008-06-05
WO2008067346A3 WO2008067346A3 (fr) 2008-08-21

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Application Number Title Priority Date Filing Date
PCT/US2007/085697 Ceased WO2008067346A2 (fr) 2006-11-30 2007-11-28 Systèmes et procédés de synchronisation rapide d'interface hertzienne sens montant

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WO (1) WO2008067346A2 (fr)

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20010055320A1 (en) * 1994-12-15 2001-12-27 Pierzga Wayne Francis Multiplex communication
US6184829B1 (en) * 1999-01-08 2001-02-06 Trueposition, Inc. Calibration for wireless location system
JP4031707B2 (ja) * 2000-12-15 2008-01-09 アダプティックス インコーポレイテッド グループベースのサブキャリア割当による多重キャリア通信
US8098683B2 (en) * 2004-10-06 2012-01-17 Broadcom Corporation Method and system for implementing a single weight (SW) single channel (SC) MIMO system with no insertion loss
US7649861B2 (en) * 2004-11-30 2010-01-19 Intel Corporation Multiple antenna multicarrier communication system and method with reduced mobile-station processing

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Publication number Publication date
WO2008067346A3 (fr) 2008-08-21

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