Abstract: A signal for relay is received from a first node. From a local memory that stores K transform matrices (K being an integer greater than one) is selected a transform matrix that is associated with a relay rank order. The matrices define an optimal tradeoff of diversity gain versus spatial multiplexing. The received signal is transformed using the selected transform matrix, and the transformed signal is relayed over a wireless channel to a second node. In a particular embodiment the received signal is an input symbol vector of N consecutive symbols (N being an integer at least equal to two) and the transform linearly combines the N symbols of the input vector according to the relay rank order. In various embodiments the first node may give the rank order, it may be mutually agreed via signaling among the various relay nodes, or it may be based on an intrinsically generated random number.

Abstract: The present application describes a method for transmitting data through a MIMO-OFDM system which requires the computation of a function f(H(sk)), where H is the channel matrix and sk=exp(j*2*pi*k/N). The method splits function f into a first, nonpolynomial part, which is in turn a function of one or more polynomial functions in sk.

Abstract: A method and apparatus for wireless transmission of a digital bit stream. The present method employs diversity techniques to minimize multipath fading. Digital bits are converted into symbols and the symbols are provided to a number of diversity branches. Each diversity branch has its own antenna. The symbols sent to each diversity branch may be multiplied by a different phase factor or amplitude factor. The phase factors and amplitude factors may be randomly selected. Also, wireless channels can be monitored for channel quality. In this case, the channel quality measurements are used to select the phase factors and the amplitude factors. Also, the symbols can be grouped into frames before transmission. In this case, the frames can be multiplied by matrices comprising phase factors and amplitude factors. Also in this case, the frames can undergo cyclic shifting, which provides an additional measure of diversity.