Revisiting of Channel Access Mechanisms in Mobile Wireless Networks through Exploiting Physical Layer Technologies

Figure 9

An example of SoftPHY hint calculation under the QPSK modulation. For uncoded channel, the hint is calculated as the distance between the received signal ’s constellation point and the decoded symbol ’s constellation point. For coded channel where a group of bits are coded to codeword, then modulated to symbols, the SoftPHY hint is calculated for this -bit stream, which is the sum of for each symbol. The codeword with a larger value is determined to be detected correctly with a higher probability.

(a) SoftPHY hint calculation for each symbol in uncoded channel

(b) SoftPHY hint calculation for each codeword in coded channel