Nortel Networks Corporation

Jian Cui

Rui R Wang

Bin Li

Wen Tong

Yuri S Shinakov

Derek Stephen Hilborn

Alan J Carter

Alexander M Shloma

Mikhail Germanovich Bakulin

Weng Tong

Vitally Kreyndelin

Tong Wen

Wayne Dam

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

An apparatus for performing collision resolution in a digital control channel which includes at least two antennas for receiving interfering signals, wherein each of the signals is associated with a network user, and a processor for processing the signals received by the antennas. The processor performs blind channel estimate calculations on the interfering signals to obtain channel information and to obtain a second signal. The second signal is selected for processing by a communication network.

Apparatus and methods for performing collision resolution for digital control channels

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

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

A demodulator, within a receiver attached to a single antenna, that cancels co-channel interference within a time division multiple access (TDMA) communication system is disclosed. The demodulator takes as input a series of received signals comprising an information signal and a co-channel interference signal, both using the &pgr;/4-differential quadrature phase shift keying (DQPSK) modulation protocol. During a training period, in which the information signals corresponds to a known SYNC word, the demodulator estimates the fading coefficients corresponding to the information and interference signals. After the completion of the training period, the demodulator uses these estimates to generate accurate estimations for future information and interference signals corresponding to future data received signals. Therefore, the information signal has been essentially separated from the co-channel interference signal and can be demodulated with a lower bit error rate (BER) than previous demodulation techniques under these circumstances.

TDMA single antenna co-channel interference cancellation

A maximal correlation symbol estimation (MCSE) method for estimating the symbols that are modulating an information signal component of a received signal, which can be applied to received signals that additionally contain an interference signal component, is disclosed. The method is achieved by correlating the received signal with all possible reference signals, each reference signal being one of a closed set of all possible information signals recognized by the given digital modulation scheme, and selecting as an estimate of the information signal the reference signal whose correlation with the received signal most closely resembles a weighted average of correlations between previously estimated information signals and their corresponding received signals. Demodulators that implement this method are adapted to perform many functions, including the estimation of symbols modulating frequency modulated (FM) received signals prior to the signals being FM demodulated. The embodiment of the MCSE demodulator adapted to carry out this last function, is designed to reduce inter-symbol interference caused by filter responses in the transmitter and receiver, and to permit each symbol to modulate a non-integer average number of signal samples.

Growing community of inventors

Nepean, Canada

Jian Cui