Motorola Corporation

Nattavut Smavatkul

Stephen P Emeott

Ye Chen

Floyd D Simpson

Huai Y Wang

Timothy J Wilson

A method for accessing a wireless local area network (WLAN) channel and providing quality of service (QoS) for voice in a system supporting both voice and data services. Under the method, a communication device () contends for a medium (channel). Upon identifying a transmit opportunity, the device transmits a voice packet to an access point (AP) () and polls the AP for downlink traffic. A low power implementation is feasible because the communication device can sleep, wake up to contend for the medium, transmit a voice packet to the AP, request a voice packet from the AP, transmit an acknowledgement, and go back to sleep.

Method of communication device initiated frame exchange

A mobile terminal () wakes up from a low power state and initiates a frame exchange in a wireless local area network that supports voice traffic by transmitting a polling frame (). If the mobile terminal had voice data to send, it is included in the polling frame. In response to receiving the polling frame, the access point transmits a delay frame () to acknowledge receipt of the polling frame. If the access point has data for the polling mobile terminal, it transmits a non-delay frame () including the voice data, otherwise it transmits a null frame (). The mobile terminal acknowledges the data from the access point (), and goes back to sleep until the beginning of the next service interval.

Method for performing transactions in a wireless local area network

An access point () for a wireless local area network () transmits a beacon message during a service interval period (). This beacon message identifies, in a preferred embodiment, those subscriber units to whom the access point will shortly be transmitting data. Subscriber units that are not identified in the beacon message and that do not have data themselves to transmit to the access point can implement a power conservation mode of operation until the next beacon message. Subscriber units that have data, such as voice information, to transmit can utilize the beacon message contents to at least estimate a likely time by when the access point will have concluded making its transmissions to the subscriber units. That estimated time can then be used to facilitate scheduling a time at which a given subscriber unit will contend for an opportunity to transmit its data to the access point. In a preferred embodiment, this scheduled transmission time can potentially occur either during a contention window that follows the service interval period or during a dynamic contention window that follows the transmissions of the access point and concludes with the conclusion of the service interval period. Subscriber units can then use intervening periods of time to effect their power conservation schemes of choice.

Method and apparatus for facilitating data transmissions

A mobile station () establishes a real time communication link via an access point () for carrying voice or other time-sensitive data. A WLAN subsystem () of the mobile station is normally kept in a low power state. Upon initiating a communication link the mobile station signals to the access point that unscheduled power save delivery mode will be used (), and the access point reserves resources to assure the necessary quality of service. The mobile station initiates a frame transaction by first powering up the WLAN subsystem (), acquiring the WLAN channel (), and transmitting a polling frame. Upon successful receipt of the polling frame the access point prepares to reply with an aggregate response. The aggregate response commences by transmitting all data in an aggregate buffer, including both reserved and unreserved data buffers. Upon successful receipt of the aggregate response, the mobile station places the WLAN subsystem back into a low power state.

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Elk Grove Village, IL, United States of America

Nattavut Smavatkul