Non-legacy preamble for wireless local area networks

Abstract

Method and apparatus for transmission and reception of a Greenfield preamble are provided. In the method and apparatus, the Greenfield preamble may be a single user (SU) preamble or a multi user (MU) preamble. As an MU preamble, the Greenfield preamble includes a short training field (STF), a first long training field (LTF), a first signal (SIG) field, at least one additional LTF, and a second SIG field. Additionally, the Greenfield preamble may be utilized for efficient transmission and reception of control information to wireless devices, whereby the control information may be indicated using the STF, the first LTF, or the first or second SIG fields.

1 . A method for receiving a preamble in multi-user (MU) multiple input multiple output (MIMO) communications, the method comprising:
 receiving the preamble comprising a short training field (STF), a first long training field (LTF), a first signal (SIG) field, at least one additional LTF, and a second SIG field, wherein the preamble is a multi-user (MU) preamble;   performing time or frequency acquisition based on the STF;   performing channel estimation based on the first LTF;   obtaining a first control information from the first SIG field; and   obtaining a second control information from the second SIG field, wherein the first control information is associated with multiple receivers and the second control information is associated with a subset of the multiple receivers.   
     
     
         2 . The method of  claim 1  wherein the first LTF comprises two long training symbols preceded by a double length cyclic prefix. 
     
     
         3 . The method of  claim 1  wherein the first SIG field indicates whether the preamble is a single user (SU) preamble or a Multi user (MU) preamble. 
     
     
         4 . The method of  claim 1  wherein cyclic redundancy check (CRC) masking of the first SIG field indicates whether the preamble is an SU preamble or an MU preamble. 
     
     
         5 . The method of  claim 1  wherein the first SIG field or the second SIG field indicates an operating bandwidth, modulation on a subchannel basis, coding information on a subchannel basis, or whether data transmission is aggregated. 
     
     
         6 . The method of  claim 1  wherein the first SIG field indicates a reference transmission power level and the second SIG field indicates an offset transmission power level relative to the reference transmission power level. 
     
     
         7 . The method of  claim 1  wherein the first SIG field or the second SIG field includes an indication of a presence of a midamble or an indication of a location of the midamble. 
     
     
         8 . The method of  claim 1  wherein the first SIG field or the second SIG field indicates usage of a short guard interval (GI) for a subsequent data transmission or the first SIG field indicates whether beamforming is performed. 
     
     
         9 . The method of  claim 1  wherein a modulation scheme indicates whether a length field of the first SIG field indicates length in bits, bytes, or orthogonal frequency division multiplexing (OFDM) symbols, or multiples of bits, bytes, or OFDM symbols. 
     
     
         10 . The method of  claim 1  wherein bit-wise repetition is performed on the first SIG field or the second SIG field, and wherein a SIG field and a repeated SIG field are separately forward error correction (FEC) encoded and interleaved prior to modulation. 
     
     
         11 . The method of  claim 1  wherein the preamble comprises four 12-tone STFs, and four LTFs or two 12-tone STFs, two 6-tone STFs, and two LTFs. 
     
     
         12 . A wireless transmit/receive unit (WTRU) for receiving a preamble in multi-user (MU) multiple input multiple output (MIMO) communications, the WTRU comprising:
 a receiver configured to receive the preamble, the preamble comprising a short training field (STF), a first long training field (LTF), a first signal (SIG) field, at least one additional LTF, and a second SIG field, wherein the preamble is a multi-user (MU) preamble; and   a processor configured to perform time or frequency acquisition based on the STF and channel estimation based on the first LTF, the processor further configured to obtain a first control information from the first SIG field and a second control information from the second SIG field, wherein the first control information is associated with multiple receivers and the second control information is associated with a subset of the multiple receivers.   
     
     
         13 . The WTRU of  claim 12  wherein the first LTF comprises two long training symbols preceded by a double length cyclic prefix. 
     
     
         14 . The WTRU of  claim 12  wherein the first SIG field indicates whether the preamble is a single user (SU) preamble or a Multi user (MU) preamble. 
     
     
         15 . The WTRU of  claim 12  wherein cyclic redundancy check (CRC) masking of the first SIG field indicates whether the preamble is an SU preamble or an MU preamble. 
     
     
         16 . The WTRU of  claim 12  wherein the first SIG field or the second SIG field indicates an operating bandwidth or whether data transmission is aggregated. 
     
     
         17 . The WTRU of  claim 12  wherein the first SIG field indicates a reference transmission power level and the second SIG field indicates an offset transmission power level relative to the reference transmission power level. 
     
     
         18 . The WTRU of  claim 12  wherein the first SIG field or the second SIG field includes an indication of the presence of a midamble or an indication of a location of the midamble. 
     
     
         19 . The WTRU of  claim 12  wherein the first SIG field or the second SIG field indicates usage of a short guard interval (GI) for a subsequent data transmission or the first SIG field indicates whether beamforming is performed. 
     
     
         20 . The WTRU of  claim 12  wherein a modulation scheme indicates whether a length field of the first SIG field indicates length in bits, bytes, or orthogonal frequency division multiplexing (OFDM) symbols, or multiples of bits, bytes, or OFDM symbols. 
     
     
         21 . The WTRU of  claim 12  wherein bit-wise repetition is performed on the first SIG field or the second SIG field, and wherein a SIG field and a repeated SIG field are separately forward error correction (FEC) encoded and interleaved prior to modulation. 
     
     
         22 . The WTRU of  claim 12  wherein the preamble comprises four 12-tone STFs, and four LTFs, or two 12-tone STFs, two 6-tone STFs, and two LTFs.