公开(公告)号：BRPI0100361B1

公开(公告)日：2015-12-15

申请号：BR0100361

申请日：2001-02-05

Applicant: LUCENT TECHNOLOGIES INC

Inventor： LI JUNYI ,  LAROIA RAJIV ,  UPPALA SATHYADEV VENKATA ,  RANGAN SUNDEEP

IPC: H04J11/00 ,  H04L27/26 ,  H04B7/26 ,  H04L5/02 ,  H04L7/00

Abstract: método e aparelho de comunicação de link ascendente entre uma estação móvel e uma estação base de um sistema de comunicação sem fio técnicas aperfeiçoadas de sincronização de temporização e de controle de acesso para uso em um sistema sem fio multiplexado de divisão de freqüência ortogonal (ofdm) ou outro tipo de sistema de comunicação sem fio. de acordo com a invenção, um sistema de controle de acesso e de sincronização de link ascendente é provido no qual as estações móveis transmitem certos sinais de temporização e de acesso em intervalos dedicados em uma seqüência de link ascendente. controle de acesso é implementado ilustrativamente como um processo de dois estágios no qual uma estação móvel determinada transmite primeiro um sinal genérico de acesso de link ascendente em um dos intervalos. se esse acesso for aceito, a estação base transmite uma confirmação de acesso contendo correções iniciais de energia e de temporização, junto com atribuições iniciais de canal no qual a estação móvel pode iniciar um processo de estabelecimento de chamada. para re-sincronização, estações móveis transmitem sinais de sincronização de temporização nos intervalos dedicados de temporização e de acesso. a estação base mede o tempo de chegada dos sinais, e envia de volta correções apropriadas de temporização. a invenção dessa forma garante que seja mantida a ortogonalidade entre as estações móveis.

公开(公告)号：CA2330776C

公开(公告)日：2008-03-18

申请号：CA2330776

申请日：2001-01-12

Applicant: LUCENT TECHNOLOGIES INC

Inventor： LI JUNYI ,  RANGAN SUNDEEP ,  LAROIA RAJIV ,  UPPALA SATHYADEV VENKATA

IPC: H04J11/00 ,  H04Q7/36 ,  H04B7/26 ,  H04J3/06 ,  H04L5/02 ,  H04L7/10 ,  H04L27/26 ,  H04Q7/38

Abstract: Signal construction, detection and estimation techniques for use in uplink timing synchronization and access control in an orthogonal frequency division multiplexed (OFDM) wireless system or other type of wireless communication system. In accordanc e with an illustrative embodiment of the invention, timing and access signals to be transmitted in designated timing and access intervals are constructed from orthogonal multitone signals. The multitone signals may be similar to multitone signals used in OFDM data transmission, except that a cyclic prefix associated with reception of the signals in a ba se station is extended to cover the timing errors of mobile stations not yet synchronized. The invention also provides design techniques which optimize the time resolvability and pe ak- to-average ratio of the multitone signals, an efficient fast Fourier transform (FFT) based technique for maximum likelihood timing estimation, and a robust linear filtering techniqu e for averaging timing estimates from different synchronizations.

公开(公告)号：CA2327980C

公开(公告)日：2007-02-13

申请号：CA2327980

申请日：2000-12-08

Applicant: LUCENT TECHNOLOGIES INC

Inventor： RANGAN SUNDEEP ,  UPPALA SATHYADEV VENKATA ,  LI JUNYI ,  LAROIA RAJIV

IPC: H04J11/00 ,  H04B1/7136 ,  H04B1/7143 ,  H04L5/02

Abstract: Tone sequences in a frequency hopping arrangement are generated and assign ed by advantageously employing a combination of a sequence generator and a sequence assignor to generate sequences and assign them on a time slot by time slot basis. In a transmitter, the sequence generator and sequence assignor, in combination wi th a user tone assignor are employed to generate and assign tone sequences to a user o n a time slot by time slot basis. In a receiver, the sequence generator and sequence assignor, in combination with a user tone identifier are employed to generate sequences a nd to identify incoming tone sequences to a user on a time slot by time slot basis . Specifically, the sequence assignment in a time slot is such that a prescrib ed plurality of sequences is assigned to a particular user. This partitioning of the tasks facilitates the use of a sequence generator that generates sequences with the desirable properties of interference and frequency diversity and, which, leaves the task of properly assigning these sequences among one or more users to the sequence assignor. The sequen ce assignor functions in such a manner that the interference and frequency diversity properties for the one or more users are preserved, and this is further facilitated by assigning sequences in such a manner that they maximally overlap prior assigned sequences. In one embodiment of the invention, a Latin square based sequence is generated in accordance with a first prescribed process. In a second embodiment of the invention, a Latin cube based sequence is generated in accordance with a second prescribed process. In a third embodiment of the invention, a Latin hypercub e of prescribed dimension based sequence is generated in accordance with a third prescribed process. In still another embodiment of the invention, the principles of the invention are employed to realize frequency band hopping.

公开(公告)号：CA2338471C

公开(公告)日：2006-11-07

申请号：CA2338471

申请日：2001-02-27

Applicant: LUCENT TECHNOLOGIES INC

Inventor： VISWANATH PRAMOD ,  RANGAN SUNDEEP ,  LI JUNYI ,  LAROIA RAJIV

IPC: H04B1/713 ,  H04J11/00 ,  H04B1/7143 ,  H04B1/7156 ,  H04B1/76 ,  H04B7/26 ,  H04L5/02 ,  H04L27/26 ,  H04Q7/36

Abstract: A base station having the strongest downlink signal is identified by utilizi ng a unique slope of a pilot tone hopping sequence being transmitted by a base station. Specifically, base station identification is realized by determining the slo pe of the strongest received pilot signal, i.e., the received pilot signal having the maximum energy. In an embodiment of the invention, the pilot tone hopping sequence i s based on a Latin Squares sequence. With a Latin Squares based pilot tone hopping sequence, all a mobile user unit needs is to locate the frequency of the pilot tones at on e time because the pilot tone locations at subsequent times can be determined from the slop e of the Latin Squares pilot tone hopping sequence. The slope and initial frequency shift of the pilot tone hopping sequence with the strongest received power is determined by employing a unique maximum energy detector. In one embodiment, the slope and initial frequency shift of the pilot signal having the strongest received power is determined by finding the slope and initial frequency shift of a predicted s et of pilot tone locations having the maximum received energy. In another embodiment, th e frequency shift of the pilot signal with the strongest, i.e., maximum, received power is estimated at each of times "t". These frequency shifts are employed in accordance with a prescribed relationship to determine the unknown slope and the initial frequency shift of the pilot signal.