Abstract:
Described is a system and a method for optimizing power consumption in a wireless device. The system may include a first computing device which includes a first wireless transducer and a second computing device which includes a second wireless transducer and a power adjusting arrangement. The second transducer wirelessly transmits to the first device first data at a first transmitting power and second data at a second transmitting power. The power adjusting arrangement determines the second transmitting power as a function of the first transmitting power and receipt data; the receipt data corresponding to one of (i) an acknowledgment from the first device of reception of the first data and a signal strength of the received first data and (ii) a lack of acknowledgment from the first device of reception of the first data.

Description:
FIELD OF INVENTION  
       [0001]     The present invention relates generally to a wireless network and a wireless device. In particular, the present invention relates to a system and method for optimizing power consumption in a wireless device.  
       BACKGROUND INFORMATION  
       [0002]     A wireless device, such as a wireless personal data assistant, may transmit and receive data via a wireless network (e.g., an 802.11 wireless LAN network). The wireless network generally includes at least one access point to receive and transmit the data.  
         [0003]     The effective transmitting radius of an access point in a wireless network depends in part on a transmitting power level of the access point. The transmitting power level may generally be controlled at the particular access point. For example, the access point with a smaller radius would generally maintain a lower transmitting power level than the access point with the larger radius. Therefore, the power level is kept high enough to effectively communicate with the wireless devices within a desired radius, but low enough not to interfere with communications with neighboring access points and/or wireless networks. However, wireless devices typically have a single transmitting power level (e.g., a maximized power level) to allow for compatibility with any access point.  
       SUMMARY OF INVENTION  
       [0004]     The present invention relates to a system and a method for optimizing power consumption in a wireless device. Described is a system and a method for optimizing power consumption in a wireless device. The system may include a first computing device which includes a first wireless transducer and a second computing device which includes a second wireless transducer and a power adjusting arrangement. The second transducer wirelessly transmits to the first device first data at a first transmitting power and second data at a second transmitting power. The power adjusting arrangement determines the second transmitting power as a function of the first transmitting power and receipt data; the receipt data corresponding to one of (i) an acknowledgment from the first device of reception of the first data and a signal strength of the received first data and (ii) a lack of acknowledgment from the first device of reception of the first data. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0005]      FIG. 1  shows an exemplary system according to the present invention.  
         [0006]      FIG. 2  shows an exemplary method according to the present invention. 
     
    
     DETAILED DESCRIPTION  
       [0007]     The present invention relates to a system and method for optimizing power consumption in a wireless device. In particular, the present invention allows for a wireless device to monitor and adjust its transmitting power level to use a minimum required power at a given time.  
         [0008]      FIG. 1  shows an exemplary embodiment of a system  10  according to the present invention. The system  10  includes a communications network  20  which may include, for example, a local area network (“LAN”), an Intranet, a wireless LAN (“WLAN”) as such 802.11, 802.15, 802.16, 802.20 or any other IP wireless LAN, the Internet, or a cellular network. The system  10  may also include a server  22  and at least one access point  24  (“AP”). The access point  24  may correspond to a cell of the system  10 . One of ordinary skill in the art will understand that the system  10  may include any number of access points  24  and/or cells and that instead of the access point  24 , there may be a conventional computing device which has a wireless transducer.  
         [0009]     The system  10  may include a plurality of computing devices having wireless communication capability, such as the wireless device  50 . The wireless device  50  may have voice, data and/or video capabilities and may be, for example, a radio or mobile phone, a personal data assistant (“PDA”), or a computer (e.g., including a wireless network PC card or a mobile processor having an integrated wireless LAN solution). The wireless device  50  may also include a conventional barcode scanner. The wireless device  50  may include a wireless transducer (not shown) to wirelessly receive and transmit data. The access point (“AP”)  24  may transmit data to the wireless devices  50  at an AP transmitting power level (e.g., 1 mW-1000 mW) and receive data transmitted from the wireless devices  50 .  
         [0010]     The wireless device  50  according to the present invention may transmit data and receive data via the access point  24  at a specific transmitting power level. The wireless device  50  may also include a power adjustment arrangement (not shown) to vary the transmitting power level depending on the required transmitting power at a given location or time. For example, the wireless device  50  may require a higher transmitting power level due to obstructions between the wireless device  50  and the access point  24 .  
         [0011]     The wireless device  50  may increase or decrease the transmitting power as, e.g., a distance between the wireless device  50  and the access point  24  changes. As shown in  FIG. 1 , for example, the wireless device  50  is first located at a distance X from the access point  24  and then moved to a further location located at a distance Y from the access point  24 . The distance Y is greater than the distance X. The transmitting power of the wireless device  50  at the distance Y therefore is greater than the transmitting power of the wireless device  50  at the distance X. Those skilled in the art would understand that there may be factors, other than distance, that may influence the need for adjusting the transmitting power.  
         [0012]     The transmitting power of the wireless device  50  according to the present invention may be adjusted manually by a user or automatically. For example, the power adjustment arrangement may automatically adjust the transmitting power as the wireless device  50  changes the locations with reference to the access point  24 . As shown in  FIG. 1 , the wireless device  50  may be moving in a general direction away from the access point  24 , e.g., from the distance X to the distance Y. The transmitting may increase as the wireless device  50  moves from the distance X to the distance Y.  
         [0013]     The transmitting power of the wireless device  50  may be varied on a continuum or in discrete steps. For example, the wireless device  50  may be transmitting data at a first transmitting power (e.g., low) at the distance X. At a certain distance between the distance X and the distance Y, the wireless device  50  may begin transmitting data at a second transmitting power (e.g., medium). Upon reaching the distance Y, the wireless device  50  may begin transmitting data at a third transmitting power (e.g., higher). In other embodiments, the transmitting power adjusts continuously between the distances X and Y.  
         [0014]      FIG. 2  shows an exemplary method  200  according to the present invention for reducing power in the wireless device  50 . In step  202 , the wireless device  50  is activated or powered on.  
         [0015]     In step  204 , the wireless device  50  creates a packet (e.g., a data or information packet) to be transmitted via the access point  24  and/or the communications network  20 . In step  206 , a first transmitting power level of the wireless device  50 , at which the packet will be transmitted, is set. The transmitting power level may be set manually or automatically. For example, the wireless device  50  may automatically set or default the transmitting power level to a lowest power level (e.g., 1 mW or less) upon activation. In other embodiments, the wireless device  50  may default to the highest or last used transmitting power level upon activation.  
         [0016]     In step  208 , the wireless device  50  transmits the packet. As one of ordinary skill in the art will understand, the wireless device  50  may or may not receive an acknowledgment from, e.g., from the server  22  and/or the AP  24  (step  210 ). If the acknowledgment is received (i.e., the transmitting power level is effective), the wireless device  50  may decrease the transmitting power level (step  212 ). As one of ordinary skill in the art will understand, the transmitting power level is decreased to determine a minimum effective transmitting power level. For example, the transmitting power level may be decreased to a second transmitting power level (e.g., decreased mW) and the wireless device  50  may transmit a second packet (step  208 ). Steps  208 - 212  may be repeated until no acknowledgment is received by the wireless device  50  (step  210 ). For example, the acknowledgment will not be received when the transmitting power level of the wireless device  50  is below a minimum effective transmitting power level.  
         [0017]     Upon the failure to receive the acknowledgment (step  210 ), the transmitting power level must then be increased (step  214 ) and another packet transmitted (step  216 ) to determine the minimum effective transmitting power level. If an acknowledgment is received (step  218 ), the minimum effective transmitting power level has been determined. The wireless device  50  may then store the minimum effective transmitting power level in a memory of the wireless device (step  220 ). If an acknowledgment is not received (step  218 ), the transmitting power level must again be increased (step  214 ) and steps  216 - 218  repeated.  
         [0018]     Additional packets (or any other data or information known to those of ordinary skill in the art) may optionally be transmitted after determining the minimum effective transmitting power level. If the acknowledgment is not received during any subsequent transmission, the transmitting power level must be readjusted. For example, the wireless device  50  moves from the distance X to the distance Y while exchanging data via the AP  24 . The transmitting power level of the wireless device  50  may be set to a first power level at the distance X. As the wireless device  50  approaches a midpoint between the distances X and Y, the wireless device  50  may fail to receive an acknowledgment from the communications network  20 . The transmitting power level may then be raised to a second power level which is higher than the first and the acknowledgment is received. As the wireless device  50  approaches the distance Y, the wireless device  50  may again fail to receive acknowledgment of a transmission. The transmitting power level may then be raised to a higher third power level at which acknowledgment is received.  
         [0019]     In the exemplary method shown in  FIG. 2  according to the present invention, a packet may be transmitted upon a user&#39;s request or at specified time intervals. For example, a wireless device may verify it&#39;s power level at specified time intervals (e.g., every 2 seconds) via a packet transmission. A packet may be transmitted (see step  208 ) in accordance with the predetermined time interval to determine if the transmitting power level may be increased or decreased. For example, the wireless device  50  may move from the distance Y back to the distance X. Beginning at the third power level, the transmitting power level may be decreased (e.g., in discrete steps or continuously) as the wireless device  50  approaches the distance X. For example, the transmitting power level may be decreased each time an acknowledgment is received. When no acknowledgment is received, the transmitting power level may be raised to the last known effective transmitting power level (as described above).  
         [0020]     In some embodiments of the present invention, the time interval for power level verification may be adjusted by a user. For example, a wireless device that resides in one location use a long time interval (e.g., several hours). A portable wireless device that is regularly transported (e.g., a PDA or mobile phone) may require a much shorter time interval (e.g., two seconds).  
         [0021]     Some of advantages of the present invention include reduced power consumption and prolonged battery life. The present invention may also reduce interference and congestion in wireless networks. For example, continuously limiting the transmitting power level to the minimum effective transmitting power level may ensure that the transmitting range of the wireless device is optimized.  
         [0022]     While specific embodiments of the invention have been illustrated and described herein, it is realized that numerous modifications and changes will occur to those skilled in the art. It is therefore to be understood that the appended claims are intended to cover all such modifications and changes as fall within the true spirit and scope of the invention.