Nortel Networks Corporation

Northern Telecom Limited

Other

Rui R Wang

Wen Tong

Vitali B Kreindeline

Mikhail G Bakouline

Alexandre M Chloma

Iouri Trofimov

Yong Li

Jian Cui

Bin Li

Yuri S Shinakov

Alexander Vasiliyevich Garmonov

Gang Li

Eddy Ning Hum

Philip H Thomas

Ming Jia

Qiang Shen

Alexander Dmitriev

Chao Wang, Legal Representative

Alauddin Javed

Adnan Abu-Dayya

Zhi Ding

Alexander M Shloma

Mikhail Germanovich Bakulin

Hong Zhao

Tong Wen

Andrey Yuriyevich Savinkov

Anatoly Gennadiyvich Filatov

Anatoli Vasilievich Kotov

Dmitry Menyailov

Yuri V Yassirev

Daniil F Vishin

Vitally Kreyndelin

Weng Tong

Dmitry Pogorilko

Peter Savinsky

Andrey Ivanovich Panas

Maxim Evgenyevich Shirokov

Sergey Olegovich Starkov

Alexandre Chloma

Mikhail Bakouline

Space-time diversity using a plurality of transmit antennas is provided with a turbo coding arrangement comprising two recursive systematic convolutional coders, to one of which input bits are supplied directly and to the other of which the information bits are supplied after interleaving of bit groups for respective symbol intervals. Symbols produced by the coders and comprising systematic and parity information are supplied to paths to the antennas alternately in successive symbol intervals to provide the space-time diversity. Arrangements are described for 2 and 4 antennas and for various convolutional codes, and an iterative decoder is also described.

Methods and apparatus for turbo space-time trellis coding

A multiple access telecommunication system is provided, which makes use of chaotic signals. Each transmitter has a chaotic system, which has at least one strange attractor in its phase space, and each receiver has chaotic systems, which corresponds to those in the transmitters from which it may receive signals. Each pair of users is assigned a set of periodic unstable orbits from a strange attractor, which that pair of users may use for signalling. At the transmitter side, a multiplexer receives data from plurality of users. These data are multiplexed in time, to produce an asynchronous data stream. The data stream is then mapped to a sequence of chaotic signals, in accordance with the set of trajectories for each transmitter and receiver pair.

Multiple access communication system using chaotic signals and method for generating and extracting chaotic signals

A plurality of data channels provide respective data rates and maximum error rates from a mobile station to a base station of a CDMA system; a pilot channel facilitates recovery of the data channels. For each data channel there is determined a channel energy to noise ratio (ENR) and a required pilot channel ENR. A maximum one of the required pilot channel ENRs is selected as an ENR for transmission of the pilot channel. A relative gain, and hence transmit signal power, for each data channel is determined from the ENR determined for the data channel and the selected maximum ENR for transmission of the pilot channel, thereby minimizing the total transmitted signal power of the mobile station. The data channel signals are spread using orthogonal Walsh codes and are combined with their determined relative gains.

Determining transmit signal powers of channels in a CDMA communications system

The invention relates to methods and apparatus for Turbo Code interleavers for use with third generation code division multiple access (3G CDMA) data. The apparatus includes a memory for receiving and temporarily storing the data, a counter and a clock coupled to the memory and counter for synchronization. The apparatus also includes a table containing a addresses that are selected by the counter. A puncturing device coupled to the table discards addresses if they are greater than a frame size. A buffer is coupled to the memory and the clock. The memory is configured to retrieve data from the selected addresses which are not discarded and forward it to the buffer for output.

Efficient implementations of proposed turbo code interleavers for third generation code division multiple access

SIR (signal to impairment power ratio) of a received signal in a communications system is determined from DC components produced by at least two successive stages of performing a non-linear operation, e.g., squaring, the signal and separating the DC component from a non-DC component for supply to the next stage. A signal power of a desired signal component of the received signal can also be determined from the DC components. The signal power can be auto-correlated, and normalized auto-correlation results which exceed a threshold can be used to determine a Doppler bandwidth of the received signal, which can be used to adaptively adjust filters used for separating the DC components.

Determining doppler bandwidth of a received signal from a determined power of a signal

Methods and apparatus for performing complex channel gain estimation from a transformer output and a non-coherent combiner output include a selector, an envelope detector, a weighting unit, a controller, store units, and an averager. The device may perform coherent complex channel gain estimation on link signals for signals transmitted by IS-95 burst randomization, and may operate on a power control group.

Carrier phase recovery of multi-rate signals

An interleaver receives incoming data frames of size N. The interleaver indexes the elements of the frame with an N &times;N index array. The interleaver then effectively rearranges (permutes) the data by permuting the rows of the index array. The interleaver employs the equation I(j,k)&equals;I(j,&agr; k&plus;&bgr; )modP) to permute the columns (indexed by k) of each row (indexed by j). P is at least equal to N , &bgr; is a constant which may be different for each row, and each &agr; is a relative prime number relative to P. After permuting, the interleaver outputs the data in a different order than received (e.g., receives sequentially row by row, outputs sequentially each column by column).

Methods and apparatus for turbo code

Construction of a Turbo code interleaver for blocks of any size is facilitated by partitioning the block into co-sets of predetermined size, permuting each co-set with an interleaver whose parameters are selected and optimized for the predetermined size, and recombining the elements of the permuted co-sets according to a predetermined order. Partitioning of the block into co-sets is accomplished by choosing a value n for the number of co-set, and assigning to each co-set those positions of the block having a common value for modulo-n of the block size. The permuted output may be punctured to maintain a desired ratio.

Interleaver using co-set partitioning

Co-channel interference with a desired signal in a receiver arrangement of a TDMA cellular radio communications system having two antennas and receivers for providing two received signals is reduced. Two sampled signals are derived from each of the two received signals by sampling the respective received signal at twice the symbol rate of the system and separating alternate samples at twice the symbol rate to produce the two sampled signals each with different samples at the symbol rate, providing a total of four sampled signals from the two antennas. These signals are linearly combined with respective weights to produce an output signal, the weights being determined to reduce co-channel interference with the desired signal represented by the output signal.

Co-channel interference reduction in wireless communications systems

Systems and methods for interleaving codes includes a processor that acts on a data frame received and stored in a memory. The processor separates portions of the data frame and permutes the portions, achieving maximum data scattering by using equations based on number theory.

Interleavers for turbo code

SIR (signal to impairment power ratio) of a received signal in a communications system is determined from DC components produced by at least two successive stages of performing a non-linear operation, e.g. squaring, the signal and separating the DC component from a non-DC component for supply to the next stage. A signal power of a desired signal component of the received signal can also be determined from the DC components. The signal power can be auto-correlated, and normalized auto-correlation results which exceed a threshold can be used to determine a Doppler bandwidth of the received signal, which can be used to adaptively adjust filters used for separating the DC components.

Determining SIR in a communications system

The invention provides a system and method for controlling transmission power of a mobile unit in a wireless communication system which minimizes transmission power overshoot caused by counteracting the effects of deep fading. The power control bits are received by the mobile unit then examined on an individual basis and also as a block of bits. Initially, each time a request to increase power is received the mobile unit increases the transmission power by 1 dB. When the mobile unit determines that a predetermined number of bits in a block each indicates a request to increase power is received the mobile unit increases the transmission power by 2 dB. After the block of increase requests, if the mobile receives a request to decrease the transmission power it increases the transmission power by 2 dB, then decreases the transmission power for the next two power control periods by 3 dB each.

Variable step size for power control bits to protect against power overshoot

An encoder for a wideband CDMA communications system comprises an outer Reed-Solomon code encoder and an inner parallel concatenated convolutional code (PCCC) or turbo code encoder. An iterative PCCC decoder, for decoding the inner code, includes summing functions in forward and feedback paths for producing extrinsic information to enhance soft decoding decisions by first and second decoders in successive decoding iterations. An outer code decoder connected following the PCCC decoder also can provide serial feedback information for enhancing iterative decisions by the PCCC decoder.

Encoding and decoding methods and apparatus

Supervisory audio tone (SAT) in a receive signal in a wireless communications system is detected using a discrete Fourier transform (DFT) supplied with samples of a filtered and decimated signal derived from the receive signal. The DFT can comprise M 2-input butterfly computation stages for computing an N-point DFT where N&equals;2,. Each of the stages m from 1 to M&minus;1 determines and stores, for each current sample at the input, at most 2,intermediate results forming only a subset of intermediate results required for computation by the next stage. Each of up to 2,other intermediate results required for computation by the next stage is produced by shifting of a respective stored intermediate result of the respective subset determined in respect of an input sample preceding the current sample by 2,samples. For example there are M&equals;5 stages for a 32-point DFT having 18 outputs, 6 outputs for each of three SAT frequencies.

Tone detection using discrete fourier transform techniques

A diversity path signal combiner includes two orthogonalizers which produce, from two received signals, two sets each of two relatively orthogonalized signals. One orthogonalized signal of each set includes one of the two received signals multiplied by a normalization factor, and the other includes a signal derived from both of the received signals, multiplied by a normalization factor. The inputs to the two orthogonalizers are relatively interchanged. Two signal combiners adaptively combine the two sets of orthogonalized signals with respective weights, and a selector selects between the resulting combined signals to produce an output combined signal.

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Ottawa, Canada

Rui R Wang