公开(公告)号：CA2333335A1

公开(公告)日：2001-09-14

申请号：CA2333335

申请日：2001-01-31

Applicant: LUCENT TECHNOLOGIES INC

Inventor： CHARRIERE PATRICK GEORGES VENC ,  BHATOOLAUL DAVID LAHIRI ,  LIM SEAU SIAN ,  CAO QIANG

IPC: H04J13/00 ,  H04B7/26 ,  H04J3/00 ,  H04M3/00 ,  H04W36/08 ,  H04W52/00 ,  H04W52/04 ,  H04W74/08 ,  H04Q7/38

Abstract: When a mobile is switched on in a cellular system, it first searches for the best cell that it can connect to and then attempts to send a message to the best cell found. In CDMA cellular systems, the likelihood of a mobile's RACH message being successfully received by a cell is largely dependent on its transmit power. Unfortunately having all mobiles transmit at the maximum power possible is in many circumstances not only unnecessary but also unacceptable due to the resultant intra-cell interferen ce generated. A cellular mobile telephone network is disclosed in which a mobile station requests service in data modulated on a common random access channel (RACH) in a form at associated with first a cell in which the mobile station is located. Base stations in cells neighbouring the first cell, are configured to demodulate the RACH message burst having the format associated with the first cell, and to pass the demodulate d data to a radio network controller (RNC). This enables the average power required for a successful RACH transmission to be reduced.

公开(公告)号：BR0005815A

公开(公告)日：2001-07-24

申请号：BR0005815

申请日：2000-12-08

Applicant: LUCENT TECHNOLOGIES INC

Inventor： BHATOOLAUL DAVID LAHIRI ,  MONOGIOUDIS PANTELIS

IPC: H04B1/707 ,  H04B7/26 ,  H03D1/00 ,  H04B7/216

Abstract: A receiver in a code-division, multiple-access (CDMA) communication system employs a preamble detector for random access channels (e.g., RACHs). RACHs may use orthogonal Gold code (OGC) sequences for preamble signature sequences and/or spreading of the preamble signature sequence with OGC sequences. A preamble detector may employ a fast orthogonal Gold transform (FOGT) for both despreading (e.g., correlation with code numbers C1,...,C256)) and for generating a decision statistic for detecting (identifying) the signature sequence used in the preamble. The spread signal of the RACH is applied to a code matched filter (CMF) matched to the spreading OGC sequence and the output signal of the CMF is sampled at the symbol rate. A fast Hadamaard transform (FHT) is applied to the sampled output of the CMF, and the exemplary 16th order code-words of the FHT match the 16 Walsh signature sequences employed to distinguish user channels transmitted by user equipment. A fast OGC transform (FOGT) may be applied to the sampled output of the CMF if OGC sequences are used as signature sequences. The signals generated by the FHT may be split into two branches for processing: a reference branch and a data branch. The reference branch processes the FHT generated signals to estimate channel response characteristics, provide a de-rotation signal, and perform frequency acquisition if required. For the reference branch, the squared magnitude of each complex FHT vector signal of length 16 is calculated and the maximum value is set as index i, where i ELEMENT ä1,.....16ü. The maximum index i is employed as a preliminary, non-coherent decision statistic corresponding to the index value of the Walsh signature sequence used for the spread signal of the access channel. The index i of the reference branch may then be used by: 1) a Walsh generator to reproduce the Walsh (BPSK) signature sequence; 2) a selector to select one of the 16 FHT output signals to estimate channel response characteristics; and 3) as a non-coherent decision statistic for subsequent processing by the detector.

公开(公告)号：CA2325649A1

公开(公告)日：2001-06-15

申请号：CA2325649

申请日：2000-11-10

Applicant: LUCENT TECHNOLOGIES INC

Inventor： BHATOOLAUL DAVID LAHIRI ,  MONOGIOUDIS PANTELIS

IPC: H04B1/707 ,  H04B7/26 ,  H04B1/69

Abstract: A receiver in a code-division, multiple-access (CDMA) communication system employs a preamble detector for random access channels (e.g., RACHs). RACHs may use orthogonal Gold code (OGC) sequences for preamble signature sequence s and/or spreading of the preamble signature sequence with OGC sequences. A preamble detector may employ a fast orthogonal Gold transform (FOGT) for both despreading (e.g ., correlation with code numbers C1,...,C256)) and for generating a decision statistic for detecting (identifying) the signature sequence used in the preamble. The spread signal of the RACH is applied to a code matched filter (CMF) matched to the spreading OGC sequence and the output signal of the CMF is sampled at the symbol rate. A fast Hadamaard transform (FHT) is applied to the sampled output of the CMF, and t he exemplary 16th order code-words of the FHT match the 16 Walsh signature sequences employed to distinguish user channels transmitted by user equipment. A fast OGC transform (FOGT) may be applied to the sampled output of the CMF if OGC sequences are used as signature sequences. The signals generated by the FHT may be split into two branches for processing: a reference branch and a data branch. The reference branch processes the FHT generated signals to estimate channel response characteristics, provide a de-rotation signal, and perform frequency acquisition if required. For the reference branch, the squared magnitude of each complex FHT vector signal of length 16 is calculated and the maximum value is set as index i, where i , { 1,.....16}. The maximum index i is employed as a preliminary, non-coherent decision statistic corresponding to the index value of the Walsh signature sequence used for the spread signal of the access channel. The ind ex i of the reference branch may then be used by: 1 ) a Walsh generator to reproduce the Walsh (BPSK) signature sequence; 2) a selector to select one of the 16 FHT output signals to estimate channel response characteristics; and 3) as a non-coherent decision statisti c for subsequent processing by the detector.

公开(公告)号：AU5074700A

公开(公告)日：2001-01-22

申请号：AU5074700

申请日：2000-06-02

Applicant: LUCENT TECHNOLOGIES INC

Inventor： BHATOOLAUL DAVID LAHIRI ,  FREIBERG LORENZ FRED

IPC: H04B1/707 ,  H04B7/005 ,  H04L25/02 ,  H04W52/32

Abstract: In a CDMA network, each mobile is arranged to combined pilot symbols from its dedicated pilot channel with pilot symbols from at least one common channel as an input to its channel impulse response sensing means. The common channel may be a BCH, a FACH or a PCH, and the pilot symbols on all such channels may be combined. The pilot energy required on each dedicated pilot channel can thereby be reduced. By communicating the quality of the received pilot symbols to a base station, the base station can reduce the energy on the dedicated pilot channel, providing a yet further saving of energy.

公开(公告)号：AU1670700A

公开(公告)日：2000-10-04

申请号：AU1670700

申请日：1999-12-10

Applicant: LUCENT TECHNOLOGIES INC

Inventor： BHATOOLAUL DAVID LAHIRI ,  LIM SEAU SIAN ,  CAO QIANG

IPC: H04L29/08 ,  H04B7/005 ,  H04L1/16 ,  H04W28/04 ,  H04W52/48 ,  H04W52/50 ,  H04W74/08 ,  H04Q7/38

Abstract: In a UMTS, the AICH is arranged to send, in addition to a signal acknowledging that a preamble from a mobile is at an acceptable strength, an additional signal indicating that the mobile is not currently permitted to send its message; this may apply when the BTS does not have hardware resources available. If the BTS can predict when the hardware will become available, the additional signal can include a time out (T) after which the mobile system can send its message signal.