WO2009138946A1 - Système et procédé de détection de code actif à base de décorrélation - Google Patents

Système et procédé de détection de code actif à base de décorrélation Download PDF

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Publication number
WO2009138946A1
WO2009138946A1 PCT/IB2009/051937 IB2009051937W WO2009138946A1 WO 2009138946 A1 WO2009138946 A1 WO 2009138946A1 IB 2009051937 W IB2009051937 W IB 2009051937W WO 2009138946 A1 WO2009138946 A1 WO 2009138946A1
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WO
WIPO (PCT)
Prior art keywords
acd
active code
engine
candidate
received signal
Prior art date
Application number
PCT/IB2009/051937
Other languages
English (en)
Inventor
Xun Fan
Original Assignee
Nxp B.V.
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 Nxp B.V. filed Critical Nxp B.V.
Publication of WO2009138946A1 publication Critical patent/WO2009138946A1/fr

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Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04J—MULTIPLEX COMMUNICATION
    • H04J13/00—Code division multiplex systems
    • H04J13/0007—Code type
    • H04J13/004—Orthogonal
    • H04J13/0044—OVSF [orthogonal variable spreading factor]
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
    • H04B1/69—Spread spectrum techniques
    • H04B1/707—Spread spectrum techniques using direct sequence modulation
    • H04B1/7097—Interference-related aspects
    • H04B1/7103—Interference-related aspects the interference being multiple access interference
    • H04B1/7105—Joint detection techniques, e.g. linear detectors
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B2201/00—Indexing scheme relating to details of transmission systems not covered by a single group of H04B3/00 - H04B13/00
    • H04B2201/69—Orthogonal indexing scheme relating to spread spectrum techniques in general
    • H04B2201/707—Orthogonal indexing scheme relating to spread spectrum techniques in general relating to direct sequence modulation
    • H04B2201/70702—Intercell-related aspects

Definitions

  • Time division- synchronous code division multiple access is a wireless communication standard based on burst transmissions, where the most basic burst unit is a time slot.
  • Fig. 1 depicts a block diagram of one embodiment of a time slot burst structure 100.
  • a TD- SCDMA system transmits signals according to a specific structure at each time slot, as shown in Fig. 1.
  • a TD-SCDMA time slot is designed to fit into exactly one burst.
  • the time slot burst structure 100 includes four parts, including a midamble with 144 chips duration, two identical data segments at each side of the midamble with 352 chips duration each, followed by a 16 chips guard period (GP) used to alleviate the effect of multipath delay.
  • a chip is one bit of a direct- sequence spread spectrum code.
  • the chip rate of a code is the number of bits per second (chips per second) at which the code is transmitted (or received).
  • the performance of active code detection directly affects the performance of joint detection (JD) and is therefore performed prior to JD.
  • the spreading codes used by all code divided users are determined.
  • the user equipment (UE) only knows about the active code channels assigned to it and is not aware of any interference users' code channels.
  • the carried data symbol information is spread by a combined spreading code of the channelization code, a channelization code specific multiplier, and a cell scrambling code.
  • the channelization codes used in TD-SCDMA systems are called orthogonal variable spreading factor (OVSF) codes.
  • the midamble of the time slot burst structure 100 includes the channelization codes (i.e., the OVSF codes) related to the midamble codes, which are used for channel estimation at the receiver.
  • TD-SCDMA standardizes three midamble allocation modes: default mode, common mode, and specific mode. Different allocation modes imply different relationships between allocated midambles and OVSF codes.
  • the system is a receiver for detecting active code channels in a received signal.
  • the receiver includes an active code candidate (ACC) engine, an active code detection (ACD) comparator, and an ACD apparatus.
  • the ACC engine receives a signal from a transmitter and determines a number of candidate active code channels contained in the received signal.
  • the received signal includes a set of candidate active code channels.
  • the ACD comparator compares the number of candidate active code channels to a predetermined size of a spreading factor and determines whether the number of candidates in the candidate active code channel set is less than the predetermined size of the spreading factor.
  • the ACD apparatus selects an ACD scheme from a plurality of ACD schemes and detects active code channels of the received signal based on the selected ACD scheme.
  • the method is a method for active code detection (ACD).
  • the ACD method includes determining a number of candidate active code channels contained in a received signal.
  • the ACD method also includes comparing the number of candidate active code channels to a predetermined size of a spreading factor.
  • the ACD method also includes selecting an ACD scheme from a plurality of ACD schemes based on the number of candidate active code channels in the candidate active code channel set relative to the predetermined size of the spreading factor.
  • the ACD method also includes detecting active code channels from the candidate active code channels based on the selected ACD scheme.
  • Other embodiments of the method are also described
  • Fig. 2 depicts a schematic block diagram of one embodiment of a receiver system with an active code detection (ACD) apparatus for the detection of an active code channel.
  • Fig. 3 depicts a schematic block diagram of one embodiment of a channel matrix based on M active code channels.
  • Fig. 4 depicts a schematic block diagram of one embodiment of an ACD apparatus for the detection of an active code channel.
  • Fig. 5 depicts an association between midambles and orthogonal variable spreading factor (OVSF) codes.
  • OVSF orthogonal variable spreading factor
  • Table 2 demonstrates that for the filtering of a symbol period, the additional complexity of M a (Q + W ) + M ⁇ is present in D-ACD over M-ACD.
  • the symbol-level de-correlation i.e., the matrix V ' based de-correlation
  • the M-ACD engine 406 performs the matched filter (MF)-based active code detection.
  • the ACD apparatus 400 designates the selected candidate as an inactive code channel and the ACD apparatus 400 selects another unknown candidate from the candidate active code channel set at block 714. Otherwise, at block 720, the ACD apparatus 400 designates the selected candidate as an active code channel and the ACD apparatus 400 selects another unknown candidate from the candidate active code channel set at block 714.
  • Fig. 8 depicts a schematic flow chart diagram of one embodiment of the de-correlation-based active code detection operation 710 of the selective code detection method 700 of Fig. 7.
  • the de-correlation-based active code detection operation 710 is described in conjunction with the ACD apparatus 400 of Fig. 4, some embodiments of the operation 710 may be implemented with other types of ACD apparatuses.
  • Embodiments of the D-ACD method 700 described with reference to Fig. 7 and illustrated with reference to Figs. 9A and 9B have a demonstrable impact on the efficiency of active code detection in downlink receivers.
  • Embodiments of the D-ACD method 700 effectively reduce the probability of errors in detecting unknown active code channels in a received signal with relatively little increase in complexity when compared to joint detection (JD) complexity.
  • embodiments of the described D-ACD method 700 provide varying tradeoffs between performance and complexity for practical receiver implementations.

Landscapes

  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Noise Elimination (AREA)

Abstract

L'invention porte sur un récepteur de détection des canaux de code actif d’un signal reçu. Le récepteur comprend un moteur de candidats de code actif (ACC); un comparateur de détection de code actif (ACD); et un appareil ACD. Le moteur ACC reçoit un signal d'un émetteur et détermine un nombre de canaux de code actif candidats contenus dans le signal reçu. Le signal reçu comprend un ensemble de canaux de code actif candidats. Le comparateur ACD compare le nombre de canaux de code actif candidats à une dimension prédéterminée d'un facteur d'étalement et détermine si le nombre de candidats dans l'ensemble de canaux de code actif candidats est inférieur ou égal à la dimension prédéterminée du facteur d'étalement. L'appareil ACD sélectionne une technique ACD parmi une pluralité de techniques ACD et détecte des canaux de code actif du signal reçu en fonction de la technique ACD sélectionnée.
PCT/IB2009/051937 2008-05-13 2009-05-12 Système et procédé de détection de code actif à base de décorrélation WO2009138946A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US5270208P 2008-05-13 2008-05-13
US61/052,702 2008-05-13

Publications (1)

Publication Number Publication Date
WO2009138946A1 true WO2009138946A1 (fr) 2009-11-19

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WO (1) WO2009138946A1 (fr)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102547813A (zh) * 2011-12-16 2012-07-04 华为技术有限公司 码道检测方法和相关装置及通信系统
CN102752013A (zh) * 2012-06-21 2012-10-24 华为技术有限公司 激活码道检测方法及装置
EP2761764A4 (fr) * 2011-09-27 2015-07-22 St Ericsson Sa Procédé et appareil pour activation de code, programme informatique et support de stockage correspondant

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1628422A1 (fr) * 2003-05-28 2006-02-22 Da Tang Mobile Communications Equipment Co., Ltd. Procede et appareil de detection d'activation d'un canal de code multi-utilisateur dans un systeme de communication sans fil
US20080080468A1 (en) * 2006-09-29 2008-04-03 Analog Devices, Inc. Architecture for joint detection hardware accelerator

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1628422A1 (fr) * 2003-05-28 2006-02-22 Da Tang Mobile Communications Equipment Co., Ltd. Procede et appareil de detection d'activation d'un canal de code multi-utilisateur dans un systeme de communication sans fil
US20080080468A1 (en) * 2006-09-29 2008-04-03 Analog Devices, Inc. Architecture for joint detection hardware accelerator

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP2761764A4 (fr) * 2011-09-27 2015-07-22 St Ericsson Sa Procédé et appareil pour activation de code, programme informatique et support de stockage correspondant
CN102547813A (zh) * 2011-12-16 2012-07-04 华为技术有限公司 码道检测方法和相关装置及通信系统
CN102547813B (zh) * 2011-12-16 2014-04-02 华为技术有限公司 码道检测方法和相关装置及通信系统
US8750347B2 (en) 2011-12-16 2014-06-10 Huawei Technologies Co., Ltd. Code channel detecting method and related device and communication system
CN102752013A (zh) * 2012-06-21 2012-10-24 华为技术有限公司 激活码道检测方法及装置
CN102752013B (zh) * 2012-06-21 2014-09-03 华为技术有限公司 激活码道检测方法及装置
US9214982B2 (en) 2012-06-21 2015-12-15 Huawei Technologies Co., Ltd. Activated code channel detection method and device

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