A method and apparatus for increasing the data rate and providing antenna diversity using multiple transmit antennas is disclosed. A set of bits of a digital signal are used to generate a codeword. Codewords are provided according to a channel code. Delay elements may be provided in antenna output channels, or with suitable code construction delay may be omitted. n signals represent n symbols of a codeword are transmitted with n different transmit antennas. At the receiver MLSE or other decoding is used to decode the noisy received sequence. The parallel transmission and channel coding enables an increase the data rate over previous techniques, and recovery even under fading conditions. The channel coding may be concatenated with error correction codes under appropriate conditions.
REFERENCE TO RELATED APPLICATIONS
This application claims priority from U.S. Provisional Application Ser. Nos. 60/017,046 filed Apr. 26, 1996 and 60/030,571 filed Nov. 7, 1996. This application is also a continuation application of U.S. patent application Ser. No. 08/847,635 filed Apr. 25, 1997, now U.S. Pat. No. 6115,427.
A method of transmitting adaptive modulation signals using space-time block code matrix from a plurality of antennas, the method comprising the steps of: changing adaptively the number of transmission repeat times of the matrix according to a propagation condition, transforming modulation signals at each transmission repeat timing from each antenna by using the matrix, and sending the transformed signals at each transmission repeat timing from each antenna.
A method of transmitting a signal in a mobile communication system using multiple antennas including allocating bit-mapped symbols to the multiple antennas based on a correlation among the multiple antennas. Further, allocating the bit-mapped symbols allocates bit-mapped symbols transmitted from antennas having a higher correlation among each other to be retransmitted from antennas having a lower correlation among each other, and allocates bit-mapped symbols transmitted from antennas having a lower correlation among each other to be retransmitted from antennas having a higher correlation among each other. In another example, allocating the bit-mapped symbols allocates the bit-mapped symbols to multiple antennas according to a detection efficiency of each symbol in addition to the correlation among the multiple antennas.
The invention relates to a method and a radio system for transmitting a digital signal. The method comprises the following steps: the transmitter transmits at least a part of the signal via at least two different transmit antenna paths; the transmitter weights the transmit power of the signals to be transmitted via the different transmit antenna paths with respect to one another by means of changeable weighting coefficients determined for each transmit antenna path; the receiver receives the signal.
A method and apparatus for mapping a stream of bits output from an encoder to a stream of bits for 2.sup.m-ary modulation. The method and apparatus divides the stream of bits from the encoder into a first period and a second period. The first period includes bits with higher priority in the stream of the bits output from the encoder, and the second period includes bits with lower priority. The method and apparatus maps the bits existing in the first period to bit positions with higher reliability in a stream of m bits representing each of the bits for 2.sup.m-ary modulation, and maps the bits existing in the second period to bit positions with lower reliability in the stream of m bits.
A method for transmitting signal in a mobile communication system allocates symbols which will be transmitted to transmitting antennas appropriately as considering detection efficiencies of symbols on a higher order modulation constellation and correlation between antennas, and thereby independent symbol transmission can be made and independence between antennas can be improved to improve accuracy of symbol detection on a receiving end and signal transmitting function of the system can be improved. Therefore, a pair of symbols having the longest distance between symbols is arranged to a pair of antennas having higher correlation and a pair of symbols having the shortest distance between symbols is arranged to a pair of antennas having lower correlation. Also, symbols having higher detection efficiency are allocated to antennas having higher correlation and symbols having lower detection efficiency are allocated to antennas having lower correlation.
