Cyclic Delay Diversity for Wireless Signal Reliability

The patent introduces asymmetric timing offsets between multiple transmitters, where each transmitter transmits the same data stream at different time instances relative to a reference transmitter. This asymmetric time-domain positioning prevents the signal cancellation that occurs with simultaneous transmission, while maintaining the diversity benefits of multiple transmitters for improved reliability and coverage.

The patent creates virtual copies of the signal path by having multiple transmitters transmit identical data streams with different time offsets. This allows a single-antenna legacy receiver to experience diversity effects that would normally require multiple receive antennas, as the time-shifted signals from different transmitters create distinct signal paths that the receiver can process independently.

The patent employs a reference transmitter that transmits the data stream at a reference time instance, establishing a known signal pattern before other transmitters transmit their time-shifted versions. This preliminary reference transmission enables legacy receivers to perform channel estimation by comparing the reference signal with the received signals from all transmitters, thereby facilitating accurate channel characterization even when multiple transmitters are transmitting simultaneously at doubled rates.