DESC_RATE_MCS0
if (rate >= DESC_RATE_MCS0 && rate <= DESC_RATE_MCS15) {
*mcs = rate - DESC_RATE_MCS0;
rx_status->rate_idx = rx_desc->rxmcs - DESC_RATE_MCS0;
if (rx_desc->rxmcs >= DESC_RATE_MCS0) {
rx_status->rate_idx = rx_desc->rxmcs - DESC_RATE_MCS0;