Systems and methods of using space time block codes

An apparatus comprising:

• a processor to:
• apply a first stream to antenna mapping scheme to a preamble portion of a packet;
• and
• apply a second stream to antenna mapping scheme to a data portion of the packet, wherein the second stream to antenna mapping scheme is applied to the data portion of the packet but not to the preamble portion of the packet, and wherein the second stream to antenna mapping scheme comprises a circulation scheme or a cyclic delay diversity (CDD) scheme.

A method comprising:

• determining a signal to noise ratio (SNR) associated with a message to be transmitted via a plurality of antennas;
• when the SNR satisfies a threshold, transmitting the message using a first mode, wherein the first mode includes:
• pre-multiplying a space time block codes (STBC) matrix with a first circulation matrix to generate first outputs to be transmitted via the plurality of antennas, wherein the first outputs are associated with a first subcarrier frequency;
• pre-multiplying the STBC matrix with a second circulation matrix to generate second outputs to be transmitted via the plurality of antennas, wherein the second outputs are associated with a second subcarrier frequency;
• and
• transmitting the first outputs and the second outputs via the plurality of antennas;
• and
• when the SNR does not satisfy the threshold, transmitting the message using a second mode.

An apparatus comprising:

• a processor to:
• determine a signal to noise ratio (SNR) associated with a message to be transmitted via a plurality of antennas;
• when the SNR satisfies a threshold, initiate transmission of the message using a first mode, wherein in the first mode the processor is configured to:
• pre-multiply a space time block code (STBC) matrix with a first circulation matrix to generate first antenna outputs to be transmitted via a plurality of antennas, wherein the first antenna outputs are associated with a first subcarrier frequency;
• pre-multiply the STBC matrix with a second circulation matrix to generate second antenna outputs to be transmitted via the plurality of antennas, wherein the second antenna outputs are associated with a second subcarrier frequency;
• and
• transmit the first antenna outputs and the second antenna outputs via the plurality of antennas;
• and
• when the SNR does not satisfy the threshold, the processor configured to initiate transmission of the message using a second mode.

A method comprising:

• receiving, at a receiver of a wireless device, a space time block code (STBC) field of a packet;
• determining a value of the STBC field;
• and
• decoding a data field of the packet based on the value of the STBC field, wherein a particular value of the STBC field indicates that the packet is decoded as a single spatial stream independent of a value of a number of space-time streams field.

A system comprising:

• a processor to:
• receive a space time block code (STBC) field of a packet;
• determine a value of the STBC field;
• and
• decode a data field of the packet based on the value of the STBC field, wherein a particular value of the STBC field indicates that the packet is decoded as a single spatial stream independent of a value of a number of space-time streams field.