The contents of a counter at a remote station is used to select a Walsh cover, which is used to cover the acknowledgment or negative acknowledgment bits sent on a new reverse acknowledgment channel (R-ACKCH). In the new reverse acknowledgment channel, the value of the acknowledgment bits for the broadcast transmissions is used to select the Walsh code sequence that covers the acknowledgment bit for the dedicated transmissions. When a base station receives an acknowledgment message from the remote station, the base station checks the Walsh cover of the message and extracts the embedded counter content. If the embedded counter content of the received acknowledgment or negative acknowledgment differs from the local counter value, the base station determines that a synchronization problem occurred, such that the remote station is not operating with the current transmission format information. Hence, the counter values act as the sequence identifiers of the Walsh masks.