A method of operating a mobile station requesting uplink access from a base station subsystem, the method comprising: receiving a first response time window reduction status from the base station subsystem, wherein the first response time window reduction status indicates that response time window reduction is enabled; receiving a response time window parameter from the base station subsystem, after receiving the first response time window reduction status, transmitting a first access request to the base station subsystem; in response to the first response time window reduction status indicating that response time window reduction is enabled, delaying looking for a response from the base station subsystem matching the first access request according to a delay interval after transmitting the first access request, wherein the duration of the delay interval is based on the response time window parameter received from the base station subsystem; initiating a response time window, RTW, of the first access request after the delay interval; during the response time window of the first access request, looking for an assignment message transmitted from the base station subsystem and matching the first access request without looking for an assignment message matching the first access request during the delay interval after transmitting the first access request; after transmitting the first access request and initiating the response time window of the first access request, receiving a second response time window reduction status from the base station subsystem, wherein the second response time window reduction status indicates that response time window reduction is disabled; after receiving the second response time window reduction status, transmitting a second access request to the base station subsystem; and responsive to transmitting the second access request and responsive to the second response time window reduction status indicating that response time window reduction is disabled, looking for an assignment message transmitted from the base station subsystem and matching the second access request without delay after transmitting the second access request. receiving a first response time window reduction status from the base station subsystem, wherein the first response time window reduction status indicates that response time window reduction is enabled; receiving a response time window parameter from the base station subsystem, after receiving the first response time window reduction status, transmitting a first access request to the base station subsystem; in response to the first response time window reduction status indicating that response time window reduction is enabled, delaying looking for a response from the base station subsystem matching the first access request according to a delay interval after transmitting the first access request, wherein the duration of the delay interval is based on the response time window parameter received from the base station subsystem; initiating a response time window, RTW, of the first access request after the delay interval; during the response time window of the first access request, looking for an assignment message transmitted from the base station subsystem and matching the first access request without looking for an assignment message matching the first access request during the delay interval after transmitting the first access request; after transmitting the first access request and initiating the response time window of the first access request, receiving a second response time window reduction status from the base station subsystem, wherein the second response time window reduction status indicates that response time window reduction is disabled; after receiving the second response time window reduction status, transmitting a second access request to the base station subsystem; and responsive to transmitting the second access request and responsive to the second response time window reduction status indicating that response time window reduction is disabled, looking for an assignment message transmitted from the base station subsystem and matching the second access request without delay after transmitting the second access request.