Methods and apparatus for generating and utilizing training codes in a space division multiplexing communication system
View Patent ↗A communication system is disclosed that comprises first and second communication apparatus. The first communication apparatus is provided with a transmitter for each of the transmission paths, which are capable of sending at least part of a communication signal to the second communication apparatus. The first communication apparatus moreover comprises training mechanisms for generating a training code to be sent to the second communication apparatus enabling a receiver to match a received signal to a corresponding transmitted signal. According to the invention, a training code is used with at least nearly ideal cyclic auto-correlation properties such that its cyclic auto-correction function is at least nearly zero for all cyclic shifts. The transmitter concurrently sends a training code in a mutually shifted manner, while the receiver is capable of performing a cyclic auto-correlation with respect to a received training signal.
1. A communication system having first communication means, second communication means and a first transmission path as well as at least one further transmission path between said first and said second communication means, in which at least the first communication means are provided with transmission means for each of said transmission paths, which are capable of sending at least part of a communication signal to the second communication means, in which at least the second communication means comprise reception means for each of said transmission paths, which are capable of receiving at least part of said communication signal, wherein the first communication means comprises:
a training generator that generates a training code to be sent to the reception means enabling the reception means to match a received signal to a corresponding transmitted signal, wherein the training generator is capable of generating a training code with at least nearly ideal cyclic auto-correlation properties such that its cyclic auto-correlation function is at least nearly zero for all cyclic shifts, in that the transmission means are capable of concurrently sending said training code in a mutually shifted manner and in that the reception means are capable of performing a cyclic auto-correlation with respect to a received training signal.
2. Communication system according to claim 1 , wherein the reception means are capable of generating the cyclic shifts of a received training code and to correlate these with said training code.
3. Communication system according to claim 1 , wherein the training code comprises a concatenation of the rows of a Fourier matrix.
4. Communication system according to claim 3 , wherein the training code has a length which is equal to the number of transmission paths or an integer multiple thereof.
5. Communication system according to claim 1 , wherein the training codes are preceded and followed by a dummy code during operation.
6. Communication system according to claim 1 , wherein the training generator comprises a pre-correction filter for processing the training codes.
7. Communication system according to claim 1 , wherein the training generator comprises storage means for storage one or more training codes.
8. Communication system according to claim 1 , wherein the training generator during operation, issue a number of at least substantially identical training codes and in that the receiving means comprise summation means to average the received training codes.
9. Communication system according to claim 1 , wherein the training generator at least during operation, issue at least substantial training codes at a substantially fixed interval and in that the reception means are provided with auto-correlation means for correlating a received signal with one or more signals received after a delay corresponding to said interval or an integer multiple thereof.