Selective sub-carrier processing

• Main Authors: Sujai Chari, Meesaraganda Surendra Raju
• Format: Patent
• Language: English
• Published: 20.11.2019
• Subjects: ELECTRIC COMMUNICATION TECHNIQUE; ELECTRICITY; TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHICCOMMUNICATION; WIRELESS COMMUNICATIONS NETWORKS

Selective subcarrier processing of a received multicarrier (OFDM) signal comprises determining whether a quality of the signal is better than a predetermined quality, selected to ensure that a probability of error free decoding is greater than a predetermined threshold. This involves determining whether the signal was received through a line-of-sight (LOS) channel or a non-line-of-sight (NLOS) channel. An approximate required signal to noise ratio (SNR) is selected based on the LOS/NLOS determination and the SNR of the signal during a preamble is compared with this. If the quality of the signal is better, a determination is then made as to which subcarriers to perform signal processing on based on a relative signal quality of each subcarrier. By not processing all subcarriers, power consumption is reduced. The subcarrier selection may involve the use of log likelihood ratios (LLRs) and a parity check matrix based on LDPC (low-density parity check) encoding. Selection may be based on the orthogonality of a channel matrix of each subcarrier. The power consumed per processed subcarrier and a probability of decoding error may be used. MAC layer information obtained from previous packets may be used. The percentage of subcarriers selected may be based on the coding rate.