An access point determines the highest signal strength at which it can detect transmissions from other access points or overlapping-basic-service-set (OBSS) client devices associated with the other access points. The access point sets an OBSS packet-detect threshold to the lesser of a minimum cell-size threshold or the highest signal strength and sets a receiver start-of-packet (RxSOP) threshold to the OBSS packet-detect threshold minus an offset. The access point avoids decoding incoming packets when respective signal strengths of the incoming packets do not satisfy the RxSOP threshold. The access point also avoids initiating transmission when incoming packets from the other access points or from the OBSS client devices have signal strengths that satisfy the OBSS packet-detect threshold.