Device-controlled adaptive delay diversity

A method comprising:

• configuring a communications subsystem of a communication device having more than one transmit chains comprising at least a first transmit chain and a second transmit chain to perform multiple-input multiple-output (MIMO) and transmit diversity uplink transmissions;
• and
• in response to receiving, via the communications subsystem from a base station, an uplink configuration for single data layer uplink full power transmission (ULFPTx) mode 1:
• accessing a precoding matrix codebook for MIMO configuring of antennas of the first and the second transmit chains;
• sequentially configuring the first and the second transmit chains to transmit an uplink signal with one of:
• (i) cyclic delay diversity;
• or (ii) linear delay diversity that delays the uplink signal transmitted by the second transmit chain with each of more than one phase shift or time delay values;
• transmitting the uplink signal using transmit diversity with sequentially changed phase shift or time delay values for the one of CDD or LDD using the precoding matrix codebook;
• monitoring at least one of a direct measure and an indirect measure of uplink signal quality at a network node for each of the sequentially changed phase shift or time delay values;
• determining an optimal phase shift or time delay value for current channel conditions of the more than one phase shift or time delay value associated with a higher measure of uplink signal quality than other ones of the more than one phase shift or time delay values;
• and
• transmitting the uplink signal via transmit diversity using the optimal phase shift or time delay value for the one of CDD or LDD.

A computer program product comprising:

• a non-transitory computer readable storage device;
• and
• program code on the computer readable storage device that when executed by a processor associated with a communication device, the program code enables the communication device to provide functionality of:
• configuring a communications subsystem having more than one transmit chains comprising at least a first transmit chain and a second transmit chain to perform multiple-input multiple-output (MIMO) and transmit diversity uplink transmissions;
• and
• in response to receiving, via the communications subsystem from a base station, an uplink configuration for single data layer uplink full power transmission (ULFPTx) mode 1:
• accessing a precoding matrix codebook for MIMO configuring of antennas of the first and the second transmit chains;
• sequentially configuring the first and the second transmit chains to transmit an uplink signal with (i) cyclic delay diversity (CDD);
• or (ii) linear delay diversity (LDD) that delays the uplink signal transmitted by the second transmit chain with each of more than one phase shift or time delay values;
• transmitting the uplink signal using transmit diversity with sequentially changed phase shift or time delay values for the one of CDD or LDD using the precoding matrix codebook;
• monitoring at least one of a direct measure and an indirect measure of uplink signal quality at a network node for each of the sequentially changed phase shift or time delay values;
• determining an optimal phase shift or time delay value for current channel conditions of the more than one phase shift or time delay value associated with a higher measure of uplink signal quality than other ones of the more than one phase shift or time delay values;
• and
• transmitting the uplink signal via transmit diversity using the optimal phase shift or time delay value for the one of CDD or LDD.