Synchronous coherent orthogonal frequency division multiplexing system, method, software and device
AssigneeMotorola, Inc.
InventorsKevin Lynn Baum, Nikhil Shashank Nadgauda
Life of this patent
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Abstract
A synchronous coherent orthogonal frequency division multiplexing, SC-OFDM, system, method, software and device include a plurality of SC-OFDM transmitters and a plurality of SC-OFDM receivers. Each of the plurality of SC-OFDM transmitters is synchronized to a reference where the reference is derived from a common source, for transmitting SC-OFDM signals. The plurality of SC-OFDM receivers is arranged to receive the SC-OFDM signals from at least one of the plurality of SC-OFDM transmitters. The SC-OFDM signals each have a cyclic extension, and the SC-OFDM signals from each SC-OFDM transmitter include at least one pilot code in accordance with a predetermined pilot code scheme.
Claims77
A synchronous coherent orthogonal frequency division multiplexing, SC-OFDM, system that includes a plurality of SC-OFDM transmitters and a plurality of SC-OFDM receivers, comprising:
- A) the plurality of SC-OFDM transmitters, wherein each SC-OFDM transmitter is synchronized to a reference where the reference is derived from a common source, for transmitting SC-OFDM signals;
- and
- B) the plurality of SC-OFDM receivers, arranged to receive the SC-OFDM signals from at least one of the plurality of SC-OFDM transmitters;
- wherein, in A and B, the SC-OFDM signals each have a cyclic extension, and the SC-OFDM signals from each SC-OFDM transmitter include at least one pilot code in accordance with a predetermined pilot code scheme.
A base unit having an SC-OFDM transmitter synchronized to a reference where the reference is derived from a common source, for transmitting SC-OFDM signals, the SC-OFDM transmitter comprising:
- A) a modulator, coupled to receive predetermined pilot codes and data, for providing at least one OFDM signal in accordance with a predetermined pilot code scheme;
- B) a cyclic extension unit, coupled to the modulator, for extending the at least one OFDM signal using a cyclic extension, and
- C) a synchronizing unit, coupled to the cyclic extension unit and to receive a time reference signal, for deriving a local reference signal from the time reference signal and synchronizing transmission of an at least one SC-OFDM signal of the SC-OFDM transmitter in accordance with the local reference signal,
- wherein, each SC-OFDM signal has a cyclic extension and each SC-OFDM signal from the SC-OFDM transmitter includes at least one pilot code in accordance with the predetermined pilot code scheme.
A base unit having a synchronous coherent orthogonal frequency division multiplexing, SC-OFDM, receiver arranged to receive at least one composite SC-OFDM signal demodulated and parsed into a plurality of composite SC-OFDM symbols and at least one composite SC-OFDM pilot code, the SC-OFDM receiver comprising:
- A) a multi-channel channel response measurement unit, arranged to receive the at least one composite SC-OFDM pilot code, for computing channel response measurements for a plurality of components of the composite SC-OFDM signal based on a plurality of associated pilot codes, and
- B) a detector, coupled to the multi-channel channel response measurement unit and to receive at least one of the plurality of composite SC-OFDM symbols, for detecting at least one symbol component from the at least one composite SC-OFDM symbol based on the channel response measurement/measurements and the at least one composite SC-OFDM symbol.
A base unit having a synchronous coherent orthogonal frequency division multiplexing, SC-OFDM, receiver unit having a plurality of diversity antennas arranged to receive a plurality of composite SC-OFDM signals demodulated and parsed into a plurality of composite SC-OFDM symbols and a plurality of composite SC-OFDM pilot codes, the SC-OFDM receiver unit comprising:
- A) a plurality of multi-channel channel response measurement units, each arranged to receive at least one composite SC-OFDM pilot code and a plurality of composite SC-OFDM symbols, for computing channel response measurements for a plurality of components for each of the plurality of composite SC-OFDM signals based on a plurality of associated pilot codes, and
- B) a diversity detector, coupled to the plurality of multi-channel channel response measurement units and to receive at least two of the plurality of composite SC-OFDM symbols, for detecting at least one symbol component from the composite SC-OFDM symbols based on the channel response measurements and the composite SC-OFDM symbols.
A subscriber unit having a synchronous, coherent, orthogonal frequency division multiplexing, SC-OFDM, transmitter synchronized to a reference where the reference is derived from a common source, for transmitting SC-OFDM signals, the SC-OFDM transmitter comprising:
- A) a modulator, coupled to receive predetermined pilot codes and data, for providing at least one OFDM signal in accordance with a predetermined pilot code scheme;
- B) a cyclic extension unit, coupled to the modulator, for extending the OFDM signal using a cyclic extension, and
- C) a synchronizing unit, coupled to the cyclic extension unit and to receive a time reference signal, for deriving a local reference signal from the time reference signal and synchronizing transmission of an SC-OFDM signal of the SC-OFDM transmitter in accordance with the local reference signal,
- wherein, the SC-OFDM signals each have a cyclic extension and the SC-OFDM signals from the SC-OFDM transmitter include at least one pilot code in accordance with a predetermined pilot code scheme.
A subscriber unit having a synchronous coherent orthogonal frequency division multiplexing, SC-OFDM, receiver arranged to receive at least one composite SC-OFDM signal demodulated and parsed into a plurality of composite SC-OFDM symbols and at least one composite SC-OFDM pilot code, the SC-OFDM receiver comprising:
- A) a multi-channel channel response measurement unit, arranged to receive the at least one composite SC-OFDM pilot code, for computing channel response measurements for a plurality of components of the composite SC-OFDM signal based on a plurality of associated pilot codes, and
- B) a detector, coupled to the multi-channel channel response measurement unit and to receive at least one of the plurality of composite SC-OFDM symbols, for detecting at least one symbol component from the at least one composite SC-OFDM symbol based on the channel response measurement/measurements and the at least one composite SC-OFDM symbol.
A subscriber unit having a synchronous coherent orthogonal frequency division multiplexing, SC-OFDM, receiver unit having a plurality of diversity antennas arranged to receive a plurality of composite SC-OFDM signals demodulated and parsed into a plurality of composite SC-OFDM symbols and a plurality of composite SC-OFDM pilot codes, the SC-OFDM receiver unit comprising:
- A) a plurality of multi-channel channel response measurement units, each arranged to receive at least one composite SC-OFDM pilot code, for computing channel response measurements for a plurality of components for each of the plurality of composite SC-OFDM signals based on a plurality of associated pilot codes, and
- B) a diversity detector, coupled to the plurality of multi-channel channel response measurement units and to receive at least two of the plurality of composite SC-OFDM symbols, for detecting at least one symbol component from the composite SC-OFDM symbols based on the channel response measurements and the composite SC-OFDM symbols.
A method for implementing synchronous coherent orthogonal frequency division multiplexing utilizing a plurality of SC-OFDM transmitters and a plurality of SC-OFDM receivers, comprising the steps of:
- A) utilizing the plurality of SC-OFDM transmitters, wherein each SC-OFDM transmitter is synchronized to a reference where the reference is derived from a common source, for transmitting SC-OFDM signals, wherein the SC-OFDM signals each have a cyclic extension, and the SC-OFDM signals include at least one pilot code in accordance with a predetermined pilot code scheme;
- and
- B) utilizing the plurality of SC-OFDM receivers, arranged for receiving the SC-OFDM signals from at least one of the plurality of SC-OFDM transmitters, for detecting information transmitted by at least one of the plurality of the SC-OFDM transmitters.
A method for implementing synchronous coherent orthogonal frequency division multiplexing transmission utilizing a plurality of OFDM transmitters, comprising the steps of:
- A) synchronizing transmission times of OFDM signals for each of the plurality of OFDM transmitters;
- B) transmitting pilot codes and data from each of the plurality of OFDM transmitters according to a predetermined pilot code scheme where the pilot codes are transmitted on a same plurality of predetermined subcarriers for each OFDM transmitter.
A method for implementing synchronous coherent orthogonal frequency division multiplexing reception utilizing an OFDM receiver arranged to receive SC-OFDM signals, comprising the steps of:
- A) demodulating and parsing the SC-OFDM signals into received pilot codes and received symbols;
- B) measuring a channel response based on at least one of the received pilot codes and a stored pilot code;
- C) recovering an estimate of transmitted information in the SC-OFDM signals based on a channel response measurement and the received symbols.
A method for providing efficient orthogonal frequency division multiplexing reception upon receiving at least one orthogonal frequency division multiplexing signal, where a receiver uses at least frequency demultiplexed signals from a plurality of subcarriers to provide a detected signal, the method comprising the steps of:
- A) measuring an average adjacent-subcarriers phase difference based on at least frequency demultiplexed signals from a plurality of subcarriers to provide a measured adjacent-subcarriers phase difference;
- and
- B) compensating for the measured average adjacent-subcarriers phase difference in the formation of the detected signal.
An orthogonal frequency division multiplexing OFDM receiver for receiving at least one orthogonal frequency division multiplexing signal, frequency demultiplexing the signal into a plurality of demultiplexed signals from a plurality of subcarriers, and for detecting at least one symbol from the demultiplexed signals, comprising:
- A) an adjacent-subcarriers phase difference measurement unit, coupled to receive the demultiplexed signals, for measuring an average adjacent-subcarriers phase difference, to provide a measured average adjacent-subcarriers phase difference;
- B) an adjacent-subcarriers phase difference compensation unit, coupled to the adjacent-subcarriers phase difference measurement unit and the demultiplexed signals, for compensating the demultiplexed signals for the measured average adjacent-subcarriers phase difference to provide compensated signals;
- and
- C) detector, coupled to the adjacent-subcarriers phase difference compensation unit, for detecting at least one symbol to provide at least one detected symbol, based on at least the compensated signals.
An orthogonal frequency division multiplexing receiver for receiving at least one orthogonal frequency division multiplexing signal, frequency demultiplexing the signal into a plurality of demultiplexed signals from a plurality of subcarriers, and for detecting at least one symbol from the demultiplexed signals, comprising:
- A) an adjacent-subcarriers phase difference measurement unit, coupled to receive the demultiplexed signals, for measuring an average adjacent-subcarriers phase difference to provide a measured average adjacent-subcarriers phase difference;
- and
- B) a detector with phase compensation unit, coupled to the adjacent-subcarriers phase difference measurement unit and the demultiplexed signals, for providing at least one detected symbol based on at least the demultiplexed signals and the measured adjacent-subcarriers phase difference.
A synchronous coherent orthogonal frequency division multiplexing, SC-OFDM, receiver for receiving at least one composite SC-OFDM signal, frequency demultiplexing the composite SC-OFDM signal into a plurality of composite SC-OFDM symbols from a plurality of subcarriers, and for detecting at least one symbol component from at least one composite SC-OFDM symbol, comprising:
- A) an adjacent-subcarriers phase difference measurement unit, coupled to receive the composite synchronous coherent orthogonal frequency division multiplexing symbols, for measuring an average adjacent-subcarriers phase difference, to provide a measured average adjacent-subcarriers phase difference;
- B) an adjacent-subcarriers phase difference compensation unit, coupled to the adjacent-subcarriers phase difference measurement unit and the composite SC-OFDM symbols, for compensating the composite SC-OFDM symbols for the measured average adjacent-subcarriers phase difference to provide compensated composite SC-OFDM symbols;
- and
- C) a detector, coupled to the adjacent-subcarriers phase difference compensation unit, for detecting at least one symbol component of at least one composite SC-OFDM symbol to provide at least one detected symbol component based on at least the compensated composite SC-OFDM symbols.
A synchronous coherent orthogonal frequency division multiplexing, SC-OFDM, receiver for receiving at least one composite SC-OFDM signal, frequency demultiplexing the composite SC-OFDM signal into a plurality of composite SC-OFDM symbols from a plurality of subcarriers, and for detecting at least one symbol component from at least one composite SC-OFDM symbol, comprising:
- A) a multichannel adjacent-subcarriers phase difference measurement unit, coupled to receive the composite SC-OFDM symbols, for measuring an average adjacent-subcarriers phase difference for a plurality of components of the composite SC-OFDM symbols, to provide a plurality of measured average adjacent-subcarriers phase differences;
- and
- B) a detector with multi-channel adjacent-subcarriers phase difference compensation unit, coupled to the multichannel adjacent-subcarriers phase difference measurement unit and the composite SC-OFDM symbols, for detecting at least one symbol component of at least one composite SC-OFDM symbol to provide at least one detected symbol component based on at least the compensated composite SC-OFDM symbols and the plurality of measured average adjacent-subcarriers phase differences.
Dependencies are inferred from the claim text.