PHY frame formats in a system with more than four space-time streams

A communication device, comprising:

• a physical layer (PHY) preamble generator configured to generate a preamble of a data unit, the PHY preamble generator including:
• a training field generator configured to generate a training field, and
• a spatial mapping module configured to apply a different spatial mapping to each of at least five instances of the training field to be included in the preamble, wherein the at least five instances of the training field correspond to at least five space-time streams;
• and
• wherein the communication device further comprises a data portion generator to cause a data portion of the data unit to be transmitted using the at least five space-time streams.

A method for sounding a communication channel, the method comprising:

• generating a set of at least five training fields, wherein the set of training fields corresponds to a set of at least five space-time streams, such that a receiver device can estimate the set of space-time streams using the set of training fields;
• mapping each training field in the set of training fields to a set of transmit chains according to a different spatial mapping vector;
• and
• causing the data unit to be transmitted with the set of at least five training fields and without a data portion.

A communication device, comprising:

• a physical layer (PHY) preamble generator configured to generate a preamble of a data unit that does not include a data portion, the PHY preamble generator including:
• a training field generator configured to generate a training field,
• a spatial mapping module configured to apply a different spatial mapping to each of at least five instances of the training field to be included in the preamble, wherein the at least five instances of the training field correspond to at least five space-time streams, and
• a block generator to generate a plurality of blocks, wherein each of the plurality of blocks includes one or more instances of the training field;
• wherein the spatial mapping module applies a different spatial mapping matrix to each of the plurality of blocks.

A method of communicating via a communication channel, the method comprising:

• generating a first data unit that includes a first set of N training fields, wherein the first set of training fields corresponds to a first set of N space-time streams associated with the communication channel;
• generating a second data unit that includes a second set of M training fields, wherein the second set of training fields corresponds to a second set of M space-time streams associated with the communication channel;
• and
• wherein the first set of space-time streams is distinct from the second set of space-time streams, such that a receiver device can estimate the N+M space-time streams associated with the communication channel using the first data unit and the second data unit.

A communication device, comprising:

• a physical layer (PHY) preamble generator configured to generate a preamble of a data unit to be transmitted via a communication channel, the PHY preamble generator including:
• a training field generator configured to generate a training field,
• a block controller configured to generate a plurality of blocks, wherein each of the plurality of blocks includes two or more instances of the training field, and
• a spatial mapping module configured to apply a different spatial mapping scheme to each of the plurality of blocks, such that each of the instances of the training field trains a different space-time stream associated with the communication channel.