Trellis coding technique to improve adjacent channel interference protection ratio in land mobile radio systems

Claim 1

A method of configuring a communication system, said system including a transmitter having an encoder with a memory length L and capable of being in a plurality of encoder states coupled to a mapper for mapping the encoder states to a phase angle signal, a pair of parallel branches coupled to an output of the mapper, each branch having a transmit filter coupled to the mapper for filtering the phase angle signal with a transfer function Q(f), a digital-to-analog (D/A) converter coupled to the transmit filter for sampling the filtered signal, a low pass filter and a modulator coupled in series with the D/A converter, a summer coupled to the modulator of each branch, and a transmit antenna coupled to the summer, said system further including a receiver comprising a circuit including a receive antenna, a first down converter, a receive filter having a power spectrum H r (f), a second down converter, an analog-to-digital converter and a decoder all serially coupled; said method comprising the steps of: a) choosing a desired minimum acceptable Euclidean distance (DMED) between a set of symbol points for the transmitter; b) choosing a symbol period, T s ; c) choosing a number of input bits to be shifted into the encoder at each said symbol period thereby determining an encoder alphabet having M entries; d) choosing a number of bits to be output by the encoder during each said symbol period to determine length of an encoder output code and a number of constellation points; e) setting a probability associated with each said encoder alphabet entry uniformly to a single predetermined value thereby fixing a probability matrix X v ; f) setting a probability associated with each said encoder output code uniformly to a single predetermined value thereby fixing a probability matrix Y v ; g) permutating all possible encoder states with all encoder alphabet entries to result in a plurality of encoder sets U; h) choosing an encoder set as a present encoder set; i) adapting the encoder to provide a plurality of encoder output codes u from the present encoder set U according to the encoder's present state and a presently received encoder alphabet entry; j) determining a minimum Euclidean distance, d 2 min , associated with the present encoder set U; k) comparing d 2 min determined from step "j" with DMED and discarding the present encoder set U if d 2 min does not exceed DMED; l) repeating steps "h"-"k" for all encoder sets; m) determining a P ib /P ab ratio for each encoder set that has not been discarded according to the following equation: ##EQU14## where and the superscript H indicates Hermitian or conjugate transpose operator, M=number of input alphabet entries, N=number of encoder states, L=memory length of the shift register encoder, and T s is the symbol duration; n) choosing from the encoder sets that have not been discarded an encoder set having the greatest P ib /P ab ratio as the optimum coding set; o) adapting the transmitter to transmit the optimum coding set for all future transmissions; p) adapting the decoder of the receiver to decode signals it receives according to the optimum coding set.

Claim 2

A method of configuring a communication system, said system including a transmitter having an encoder with a memory length L and capable of being in a plurality of encoder states coupled to a mapper for mapping the encoder states to a phase angle signal, a pair of parallel branches coupled to an output of the mapper, each branch having a transmit filter coupled to the mapper for filtering the phase angle signal with a transfer function Q(f), a digital-to-analog (D/A) converter coupled to the transmit filter for sampling the filtered signal, a low pass filter and a modulator coupled in series with the D/A converter, a summer coupled to the modulator of each branch, and a transmit antenna coupled to the summer, said system further including a receiver comprising a circuit including a receive antenna, a first down converter, a receive filter having a power spectrum H r (f), a second down converter, an analog-to-digital converter and a decoder all serially coupled; said method comprising the steps of: a) choosing a desired minimum acceptable Euclidean distance (DMED) between a set of symbol points for the transmitter; b) choosing a symbol period, T s ; c) choosing a number of input bits to be shifted into the encoder at each said symbol period thereby determining an encoder alphabet having M entries; d) choosing a number of bits to be output by the encoder during each said symbol period to determine length of an encoder output code and a number of constellation points; e) setting a probability associated with each said encoder alphabet entry uniformly to a single predetermined value thereby fixing a probability matrix X v ; f) setting a probability associated with each said encoder output code uniformly to a single predetermined value thereby fixing a probability matrix Y v ; g) permutating all possible encoder states with all encoder alphabet entries to result in a plurality of encoder sets U; h) choosing an encoder set as a present encoder set; i) adapting the encoder to provide a plurality of encoder output codes u from the present encoder set U according to the encoder's present state and a presently received encoder alphabet entry; j) determining a minimum Euclidean distance, d 2 min , associated with the present encoder set U; k) comparing d 2 min determined from step "j" with DMED and discarding the present encoder set U if d 2 min does not exceed DMED; l) repeating steps "h"-"k" for all encoder sets; m) determining a P ib /P ab ratio for each encoder set that has not been discarded according to the following equation: ##EQU14## where and the superscript H indicates Hermitian or conjugate transpose operator, M=number of input alphabet entries, N=number of encoder states, L=memory length of the shift register encoder, and T s is the symbol duration; n) choosing from the encoder sets that have not been discarded an encoder set having the greatest P ib /P ab ratio as the optimum coding set; o) adapting the transmitter to transmit the optimum coding set for all future transmissions; p) adapting the decoder of the receiver to decode signals it receives according to the optimum coding set.

Claim 3

A method of configuring a communication system, said system including a transmitter having an encoder with a memory length L and capable of being in a plurality of encoder states coupled to a mapper for mapping the encoder states to a phase angle signal, a pair of parallel branches coupled to an output of the mapper, each branch having a transmit filter coupled to the mapper for filtering the phase angle signal with a transfer function Q(f), a digital-to-analog (D/A) converter coupled to the transmit filter for sampling the filtered signal, a low pass filter and a modulator coupled in series with the D/A converter, a summer coupled to the modulator of each branch, and a transmit antenna coupled to the summer, said system further including a receiver comprising a circuit including a receive antenna, a first down converter, a receive filter having a power spectrum H r (f), a second down converter, an analog-to-digital converter and a decoder all serially coupled; said method comprising the steps of: a) choosing a desired minimum acceptable Euclidean distance (DMED) between a set of symbol points; b) choosing a symbol period, T s ; c) choosing a number of input bits to be shifted into the encoder at each said symbol period thereby determining an encoder alphabet having M entries; d) choosing a number of bits to be output by the encoder during each said symbol period to determine a length of an encoder output code and a number of constellation points; e) setting a probability associated with each said encoder alphabet entry uniformly to a single predetermined value thereby fixing a probability matrix X v ; f) setting a probability associated with each encoder output code uniformly to a single predetermined value thereby fixing a probability matrix Y v ; g) permutating all possible encoder states with all said encoder alphabet entries to result in a plurality of encoder sets U; h) choosing an encoder set as a present encoder set; i) adapting the encoder to provide a plurality of encoder output codes u from the present encoder set U according to the encoder's present state and a presently received encoder alphabet entry; j) determining a minimum Euclidean distance, d 2 min , associated with the present encoder set U; k) comparing d 2 min calculated from step "j" with DMED, if d 2 min does not exceed DMED, the present encoder set U is discarded; l) repeating steps "h"-"k" for all encoder sets U; m) empirically determining the peak to average power ratio of the encoder for each encoder set U that have not been discarded; n) choosing an encoder set from the encoder sets that have not been discarded having the greatest peak to average power ratio as the optimum coding set; o) adapting the transmitter to transmit the optimum coding set for all future transmissions; p) adapting the decoder to decode signals it receives according to the optimum coding set.

Claim 4

A method of configuring a communication system, said system including a transmitter having an encoder with a memory length L and capable of being in a plurality of encoder states coupled to a mapper for mapping the encoder states to a phase angle signal, a pair of parallel branches coupled to an output of the mapper, each branch having a transmit filter coupled to the mapper for filtering the phase angle signal with a transfer function Q(f), a digital-to-analog (D/A) converter coupled to the transmit filter for sampling the filtered signal, a low pass filter and a modulator coupled in series with the D/A converter, a summer coupled to the modulator of each branch, and a transmit antenna coupled to the summer, said system further including a receiver comprising a circuit including a receive antenna, a first down converter, a receive filter having a power spectrum H r (f), a second down converter, an analog-to-digital converter and a decoder all serially coupled; said method comprising the steps of: a) choosing a desired minimum acceptable Euclidean distance (DMED) between a set of symbol points; b) choosing a symbol period, T s ; c) choosing a number of input bits to be shifted into the encoder at each said symbol period thereby determining an encoder alphabet having M entries; d) choosing a number of bits to be output by the encoder during each said symbol period to determine a length of an encoder output code and a number of constellation points; e) setting a probability associated with each said encoder alphabet entry uniformly to a single predetermined value thereby fixing a probability matrix X v ; f) setting a probability associated with each encoder output code uniformly to a single predetermined value thereby fixing a probability matrix Y v ; g) permutating all possible encoder states with all said encoder alphabet entries to result in a plurality of encoder sets U; h) choosing an encoder set as a present encoder set; i) adapting the encoder to provide a plurality of encoder output codes u from the present encoder set U according to the encoder's present state and a presently received encoder alphabet entry; j) determining a minimum Euclidean distance, d 2 min , associated with the present encoder set U; k) comparing d 2 min calculated from step "j" with DMED, if d 2 min does not exceed DMED, the present encoder set U is discarded; l) repeating steps "h"-"k" for all encoder sets U; m) empirically determining the peak to average power ratio of the encoder for each encoder set U that have not been discarded; n) choosing an encoder set from the encoder sets that have not been discarded having the greatest peak to average power ratio as the optimum coding set; o) adapting the transmitter to transmit the optimum coding set for all future transmissions; p) adapting the decoder to decode signals it receives according to the optimum coding set.

Claim 6

A method of configuring a communication system, said system including a transmitter having an encoder with a memory length L and capable of being in a plurality of encoder states coupled to a mapper for mapping the encoder states to a phase angle signal, a pair of parallel branches coupled to an output of the mapper, each branch having a transmit filter coupled to the mapper for filtering the phase angle signal with a transfer function Q(f), a digital-to-analog (D/A) converter coupled to the transmit filter for sampling the filtered signal, a low pass filter and a modulator coupled in series with the D/A converter, a summer coupled to the modulator of each branch, and a transmit antenna coupled to the summer, said system further including a receiver comprising a circuit including a receive antenna, a first down converter, a receive filter having a power spectrum H r (f), a second down converter, an analog-to-digital converter and a decoder all serially coupled; said method comprising the steps of: a) choosing a desired minimum acceptable value, (MPR), of power ratio P ib /P ab ; b) choosing a symbol period, T s ; c) choosing a number of input bits to be shifted into the encoder at each said symbol period thereby determining an encoder alphabet having M entries; d) choosing a number of bits to be output by the encoder during each symbol period to determine a length of an encoder output code and a number of constellation points; e) setting a probability associated with each said encoder alphabet entry uniformly to a single predetermined value thereby fixing a probability matrix X v ; f) setting a probability associated with each said encoder output code uniformly to a single predetermined value thereby fixing a probability matrix Y v ; g) permutating all possible encoder states with all encoder alphabet entries to result in a plurality of encoder sets U; h) choosing an encoder set as a present encoder set; i) determining a P ib /P ab ratio for the present encoder set U according to the following equation: ##EQU15## where and the superscript H indicates Hermitian or conjugate transpose operator, M=number of input alphabet entries, N=number of encoder states, L=memory length of the shift register encoder, and T s is the symbol duration; j) adapting the encoder to provide a plurality of encoder output codes u from the present encoder set U according to the encoder's present state and a presently received encoder alphabet entry; k) comparing MPR with P ib /P ab calculated from step "i", if P ib /P ab does not exceed MPR, the present encoder set U is discarded, l) repeating steps "h"-"k" for all encoder sets U; m) determining minimum Euclidean distance between coded sequences, d 2 min for each encoder set U that have not been discarded; n) choosing from the encoder sets that have not been discarded an encoder set having the greatest d 2 min as the optimum coding set; o) adapting the transmitter to transmit the optimum coding set for all future transmissions; p) adapting the decoder to decode signals it receives according to the optimum coding set.

Claim 7

A method of configuring a communication system, said system including a transmitter having an encoder with a memory length L and capable of being in a plurality of encoder states coupled to a mapper for mapping the encoder states to a phase angle signal, a pair of parallel branches coupled to an output of the mapper, each branch having a transmit filter coupled to the mapper for filtering the phase angle signal with a transfer function Q(f), a digital-to-analog (D/A) converter coupled to the transmit filter for sampling the filtered signal, a low pass filter and a modulator coupled in series with the D/A converter, a summer coupled to the modulator of each branch, and a transmit antenna coupled to the summer, said system further including a receiver comprising a circuit including a receive antenna, a first down converter, a receive filter having a power spectrum H r (f), a second down converter, an analog-to-digital converter and a decoder all serially coupled; said method comprising the steps of: a) choosing a desired minimum acceptable value, (MPR), of power ratio P ib /P ab ; b) choosing a symbol period, T s ; c) choosing a number of input bits to be shifted into the encoder at each said symbol period thereby determining an encoder alphabet having M entries; d) choosing a number of bits to be output by the encoder during each symbol period to determine a length of an encoder output code and a number of constellation points; e) setting a probability associated with each said encoder alphabet entry uniformly to a single predetermined value thereby fixing a probability matrix X v ; f) setting a probability associated with each said encoder output code uniformly to a single predetermined value thereby fixing a probability matrix Y v ; g) permutating all possible encoder states with all encoder alphabet entries to result in a plurality of encoder sets U; h) choosing an encoder set as a present encoder set; i) determining a P ib /P ab ratio for the present encoder set U according to the following equation: ##EQU15## where and the superscript H indicates Hermitian or conjugate transpose operator, M=number of input alphabet entries, N=number of encoder states, L=memory length of the shift register encoder, and T s is the symbol duration; j) adapting the encoder to provide a plurality of encoder output codes u from the present encoder set U according to the encoder's present state and a presently received encoder alphabet entry; k) comparing MPR with P ib /P ab calculated from step "i", if P ib /P ab does not exceed MPR, the present encoder set U is discarded, l) repeating steps "h"-"k" for all encoder sets U; m) determining minimum Euclidean distance between coded sequences, d 2 min for each encoder set U that have not been discarded; n) choosing from the encoder sets that have not been discarded an encoder set having the greatest d 2 min as the optimum coding set; o) adapting the transmitter to transmit the optimum coding set for all future transmissions; p) adapting the decoder to decode signals it receives according to the optimum coding set.