An efficient hierarchy schedule sensing (HSS) spreading code protocol is proposed for wireless DS/CDMA networks. It uses a central pilot frame to schedule request transmissions to avoid collisions. To reduce the scheduling time, hierarchical group-based spreading codes are employed. A two-dimensional continous time Markov chain is used to model the behaviour of the HSS protocol. The performance is evaluated under various channel traffic loads. The results show that the HSS protocol offers a robust performance without much extra hardware cost if compared with conventional receiver-based spreading code protocols.