The invention relates in general to wireless data reception, and in particularly, to a Wireless Local Area Network (WLAN) data reception method and device.
Power efficiency remains an important issue for wireless device, which typically employ portable power storage cells such as batteries, storage capacity of which is inherently limited, requiring effective power management solution.
An IEEE 802.11 based WLAN operates under either an infrastructure mode or an ad-hoc mode. In infrastructure mode, the WLAN comprises wireless clients and a wireless access point (AP), whereby wireless clients can communicate with each other or an intranet; whereas in ad-hoc mode, the WLAN constitutes wireless clients only, communicating with each other without wireless AP.
WLAN deploys Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA) scheme as the data access method. In CSMA/CA scheme the transmission media is shared by every station including every wireless client and AP in the network. Any station wishing to transmit must detect the condition of the radio channel in advance. The station may transmit data if the radio channel is free. If the channel is already occupied by a data transmission, the station has to wait until the channel is released again. The duration of channel occupation is referred as “Busy Medium” period. Upon completion of each Busy Medium period, the regulation requires each station to postpone for a finite period of time, known as an Interframe Space (IFS) period, prior to enquiring for the next transmission session.
As WLAN data is broadcasted in the WLAN network, each wireless client can identify the validity of the data through the recipient address in the WLAN data frame. Conventionally, each wireless client in the WLAN network receives a complete WLAN data frame, and retains or discards the WLAN data depending on the recipient address. If the recipient address does not correspond to the wireless client, unnecessary power is expended retrieving the WLAN data frame.
Thus a method and device for WLAN data reception is presented in the present invention to control power utilization of a WLAN receiver.
A method of receiving data comprises receipt of first data in a receiving module of a receiver, determining second data from the first data, and disabling the receiving module if the second data does not correspond to identity information in the receiver.
A device for receiving data comprises a receiving module and a controller module. The receiving module receives first data. The controller module, coupled to the receiving module, determines second data from the first data, and disables the receiving module if the second data does not correspond to an identity information of the receiver.
Another method of receiving data comprises receipt of first data in a receiving module of a receiver, determining recipient address from the first data, disabling the receiving module if the recipient address does not correspond to a receiver address of the receiver, and enabling the receiving module upon expiration of an Interframe Space associated period.
The invention will become more fully understood from the detailed description, given hereinbelow, and the accompanying drawings. The drawings and description are provided for purposes of illustration only and, thus, are not intended to be limiting of the present invention.
FIGS. 4 (a) and (b) are timing diagrams of WLAN signals with correct recipient address and with incorrect recipient address incorporating the WLAN receiver in
Receiver 20 may further comprise a MAC module 204 coupled to receiving module 200, accepting and executing WLAN operations based on the first data.
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Upon receipt of WLAN data, receiving module 200 receives first data in the air and delivers the first data to controller module 202 in step s500, which in turn determines second data including recipient information from the first data in step s502.
In step s504, controller module 202 then compares the recipient information with the identity information of receiver 20. The identity information is uniquely assigned to each wireless client in the WLAN network to distinguish thereamong. The recipient information may be a recipient address for the immediate data recipient. The identity information may be an unique receiver address stored in receiver 20.
If the recipient information of the data corresponds to the identity information of receiver 20, the data is accepted and continuously retrieved for a complete data frame, as in step s506.
In step s508, if the recipient information does not match the identity information, the data is rejected and receiving module 200 is disabled by suppressing the clock signal fed thereto, or by resetting receiver 20.
In step s510, as a first period, corresponding to the completion of invalid data frame, passes, receiving module 200 is enabled once again to receive a subsequent data frame. The enablement is accomplished by issuing clock signal to receiver 20 and entering the normal data receiving procedure in step s500. Since each station in a WLAN network has to wait for a specified time interval, known as Interframe Space (IFS), prior to sending an inquiry for subsequent data transmission, the first period also correspond to Interframe Space.
In receiver 20, MAC module 204 accepts the data from receiving module 200 and responds according to WLAN specification.
After initialization of receiver 20, in step s600 first data is received at receiving module 200, followed by step s602, where the first data is directed to controller module 202 to determine the recipient address thereof. If the recipient address does not correspond to a receiver address of receiver 20, receiving module 200 is then disabled in step s604. In step s606, receiving module 302 is enabled again upon the passing of an Interframe Space associated period. The data reception method then loops back to step s600 for retrieval of next data in receiving module 200 until the receiving process is terminated.
While the invention has been described by way of example and in terms of preferred embodiment, it is to be understood that the invention is not limited thereto. To the contrary, it is intended to cover various modifications and similar arrangements (as would be apparent to those skilled in the art). Therefore, the scope of the appended claims should be accorded the broadest interpretation so as to encompass all such modifications and similar arrangements.