Transmitter optimization for spectrally congested radio communication systems

Claim 1

A method of configuring a communication system for communicating signals on adjacent channels, said system including a transmitter having an encoder with a memory length L and capable of being in a plurality of encoder states N, a mapper coupled to said encoder, a transmit filter with a transfer function D(f) coupled to said mapper, a low pass filter having a transfer function L(f) coupled to said transmit filter and a modulator coupled to said low pass filter, said system further including a receiver including a receive filter having a power spectrum H r (f) and a decoder coupled to said receive filter, comprising the steps of: a) choosing a symbol period T s ; b) determining a combined power spectrum E(f) for the encoder and mapper; c) solving the following equation, which is a standard eigenvalue problem, for a maximum eigenvalue λ, and its corresponding eigenvector d opt which represents a set of transmitter coefficients: D.sup.-1 Nd.sub.opt =λd.sub.opt where N and D are a plurality of matrices each defined respectively by: ##EQU16## where i, j range from 0 through M-1; f is frequency, f.sub.Δ is the frequency separation between said adjacent channels, b is a number of samples in sample period T s , W r is the one-sided bandwidth of the receive filter; and d) initializing said transmit filter to the optimum transmit filter coefficients d opt for future transmissions so as to result in a communications system having an increased adjacent channel interference protection ratio.

Claim 2

A method of configuring a communication system for communicating signals on adjacent channels, said system including a transmitter having an encoder with a memory length L and capable of being in a plurality of encoder states N, a mapper coupled to said encoder, a transmit filter with a transfer function D(f) coupled to said mapper, a low pass filter having a transfer function L(f) coupled to said transmit filter and a modulator coupled to said low pass filter, said system further including a receiver including a receive filter having a power spectrum H r (f) and a decoder coupled to said receive filter, comprising the steps of: a) choosing a symbol period T s ; b) determining a combined power spectrum E(f) for the encoder and mapper; c) solving the following equation, which is a standard eigenvalue problem, for a maximum eigenvalue λ, and its corresponding eigenvector d opt which represents a set of transmitter coefficients: D.sup.-1 Nd.sub.opt =λd.sub.opt where N and D are a plurality of matrices each defined respectively by: ##EQU16## where i, j range from 0 through M-1; f is frequency, f.sub.Δ is the frequency separation between said adjacent channels, b is a number of samples in sample period T s , W r is the one-sided bandwidth of the receive filter; and d) initializing said transmit filter to the optimum transmit filter coefficients d opt for future transmissions so as to result in a communications system having an increased adjacent channel interference protection ratio.