摘要:
An interleaver receives incoming data frames of size N. The interleaver indexes the elements of the frame with an N1×N2 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)=I(j,&agr;jk+&bgr;j)modP) to permute the columns (indexed by k) of each row (indexed by j). P is at least equal to N2, &bgr;j is a constant which may be different for each row, and each &agr;j 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).
摘要:
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.
摘要:
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.
摘要:
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.
摘要:
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.
摘要:
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.
摘要:
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.