Abstract:
A method and system is disclosed for a device to quickly determine if data is being sent to it. If no data is being sent to the device, the device may return to a sleep mode so as to conserve energy. The present invention includes organizing and transmitting, one at a time, all device destination identifiers. If a message listing search indicates that no message is being sent for a device, the device can continue with any other activity that needs servicing, or if no other activity is pending, it may shut down to conserve power until the next wake up period arrives. If the search returns a positive indication, the count value when the identifier is found can be used to determine the location of the pointer to the message.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a continuation of U.S. patent application Ser. No. 11/081,294 filed on Mar. 16, 2005, which is a continuation of U.S. patent application Ser. No. 10/334,433 filed on Dec. 30, 2002, which issued as U.S. Pat. No. 6,950,684 on Sep. 27, 2005, which claims the benefit of U.S. Provisional Application No. 60/377,038, filed on May 1, 2002, the contents of each which are incorporated by reference herein. 
     
    
     FIELD OF INVENTION 
       [0002]    The present invention relates to the field of wireless communications. More specifically, the present invention relates to the optimization of power resources of wireless devices within wireless communications systems. 
       BACKGROUND 
       [0003]    Portable electronic devices frequently run off of batteries. Data delivered to the devices is often short (e.g. email, instant messaging, numerical updates, status changes). The power dissipated by the devices while looking for transmissions that may be directed to them can often exceed the power required to receive such transmissions. Moreover, the devices typically only occasionally have transmissions directed to them. Despite the fact that most devices only occasionally have transmissions directed to them, the devices must nevertheless stay awake for the entire notification period. This means that many devices are dissipating power during the entire notification period, even though usually there is no data for them. 
         [0004]    It would therefore be desirable for devices to be able to quickly determine if data is being sent to them, and if not return to a sleep mode so as to conserve energy. 
       SUMMARY 
       [0005]    The present invention is a method and system for optimizing power resources in wireless devices. The invention utilizes message lists adapted to allow devices to quickly determine whether the list contains a message for them thereby decreasing the amount of time devices must be awake while searching for messages. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0006]      FIG. 1  is a message listing wherein a count of the number of destination identifiers included in the message listing is provided at the beginning of the message listing and further wherein all of the destination identifiers are listed before all the respective pointers in accordance with an embodiment of the present invention. 
           [0007]      FIG. 2  is a message listing wherein a count of the number of destination identifiers included in the message listing is provided at the beginning of the message listing and further wherein each destination identifier and its associated pointer are listed together in increasing numeric order in accordance with an embodiment of the present invention. 
           [0008]      FIG. 3  is a flow diagram showing method steps for devices to determine whether a message listing as shown in either  FIG. 1  or  FIG. 2  includes any messages for the devices, where the devices are expecting a single message within the message listing, in accordance with an embodiment of the present invention. 
           [0009]      FIG. 4  is a flow diagram showing method steps for devices to determine whether a message listing as shown in either  FIG. 1  or  FIG. 2  includes any messages for the devices, where the devices are expecting more than one message with the same identifier within the message listing, in accordance with an embodiment of the present invention. 
           [0010]      FIG. 5  is a flow diagram showing method steps for devices to determine whether a message listing as shown in either  FIG. 1  or  FIG. 2  includes any messages for the devices, where the devices are expecting more than one message with the same identifier or multiple identifiers within the message listing, in accordance with an embodiment of the present invention. 
           [0011]      FIG. 6  is a message listing wherein a list terminator is included at the end of the message and further wherein each destination identifier and its associated pointer are listed together in increasing numeric order in accordance with an embodiment of the present invention. 
           [0012]      FIG. 7  is a flow diagram showing method steps for devices to determine whether a message listing as shown in either  FIG. 6  includes any messages for the devices in accordance with an embodiment of the present invention. 
           [0013]      FIG. 8  is a system for optimizing power resources in wireless devices in accordance with an embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0014]    The preferred embodiments of the present invention will be described with reference to the drawing figures wherein like numerals represent like elements throughout. 
         [0015]    Referring initially to  FIG. 1 , there is shown a message listing  10 . Wireless devices are typically synchronized with a network so that the devices know to wake up at predetermined periods and check to see if there are any messages for them. To conserve battery, it is preferable for wireless devices to not only be asleep between the predetermined periods, but also to spend as little time as possible determining whether there is a message for them. Wireless devices typically determine whether they are the intended recipient of a message by checking a message listing. Message listings of the prior art include not only a plurality of identifiers indicative of the destination of each message contained in the listing as well as a count of the number of messages therein, but also the messages themselves. Including the messages themselves in the message listing increases the time which wireless devices must remain awake while determining whether a message listing includes a message for them. For example, where a message listing includes  10  messages listed in increasing order of destination identifiers and there are messages for devices one through four, a wireless device having a device identifier “ 5 ” must stay awake for not only the first four message identifiers, but also the first four messages themselves. Once device “ 5 ” receives its message it may go back asleep until the next message listing is received, which as mentioned, occurs at predetermined intervals. 
         [0016]    To decrease the time which devices must remain awake while determining whether particular message listings include a message for them, the present invention arranges message listings as shown in  FIGS. 1 ,  2  and  6 . Those message listings may be modified as desired/needed to maximize the message determination process without departing from the scope of the present invention. 
         [0017]    Referring initially to  FIG. 1  a first embodiment of a message listing  10  in accordance with the present invention is shown. The message listing  10  includes a count of the number of destination identifiers included in the message listing and is provided at the beginning of the message listing  10 . In this embodiment, the count is indicated with reference numeral  12  and is entitled “count of identifiers listed.” The destination identifiers 1-N , referred to generally with reference numeral  14 , are listed in increasing numeric order. Each destination identifier 1-N  has an associated message pointer. The message pointers 1-N , in this embodiment, are also listed in increasing numeric order and are generally referred to with reference numeral  16 . 
         [0018]    In an alternate embodiment, as shown in  FIG. 2 , the message listing  10  may be configured so that the message pointers 1-N    16  follow their associated destination identifiers 1-N    14 . It should be noted that, in  FIGS. 1 and 2 , the destination identifiers 1-N    14  are organized in increasing monotonic numeric order with their associated message pointers 1-N 16 , but may also be organized in decreasing monotonic numeric order. 
         [0019]    A logic diagram showing a method  30  for determining whether a message has arrived for a wireless device is shown in  FIG. 3 . The wireless device may be any type of wireless device such as, for example, a wireless telephone, a personal digital assistant, or pocket size personal computer. The methods shown in  FIGS. 3 ,  4 , and  5  may be applied for both embodiments of message listings shown in  FIGS. 1 and 2 . 
         [0020]    The method  30  begins with step  32  by initializing a search pointer of the device to a first identifier and loading the count of identifiers listed into a count variable (i.e. a register or memory unit that contains the count). The method  30  then proceeds to step  34  to determine whether the count is equal to zero. If the count is equal to zero, the method  30  proceeds to step  36  wherein the message flag is cleared. If the count is not equal to zero, the method proceeds to step  38 . In step  38 , the destination identifier pointed to by the pointer search is loaded by the device. The device preferably loads the destination identifier into a processing element of the device. Once the destination identifier is loaded by the device, the method  30  proceeds to step  40  wherein the destination identifier is compared with the device identifier to determine whether the destination identifier is greater than the device identifier. If yes, there are no subsequent messages for the device and the method  30  proceeds to step  36  where, as mentioned, the message flag is cleared. If no, the method  30  proceeds to step  42  wherein it is determined whether the destination identifier is equal to the device identifier. If the destination identifier is equal to the device identifier, there is a message for the device and the method  30  proceeds to step  44 . In step  44 , the message flag is set and a pointer to the message corresponding to the destination identifier is loaded. If the destination identifier is not equal to the device identifier, the method  30  proceeds from step  42  to step  46 . In step  46 , the search pointer is advanced to the next destination identifier and in step  48  the count is decreased. 
         [0021]    Referring now to  FIG. 4 , a method  50  for determining whether a message has arrived for a wireless device is shown. In this embodiment the devices are expecting more than one message with the same device identifier within the message listing. The method  50  begins with step  52  wherein a search pointer of a wireless device is initialized to a first identifier, the count of identifiers listed is loaded into a count variable, and the message list and message flag are cleared. From step  52 , the method proceeds to step  54  where it is determined whether the count of the identifiers listed is equal to zero. If the count is equal to zero, the method  50  ends at step  56 . If the count is not is equal to zero, the method  50  proceeds to step  58  wherein the destination identifier pointed to by the search pointer is loaded by the wireless device. From step  58 , the method  50  proceeds to step  60  where it is determined whether the destination identifier is greater than the device identifier. If the destination identifier is greater than the device identifier the method  50  proceeds to step  56  where, as mentioned, the method ends. If the destination identifier is not greater than the device identifier, the method  50  proceeds to step  62  where it is determined whether the destination identifier is equal to the device identifier. 
         [0022]    In step  62 , if the destination identifier is equal to the device identifier, a message flag is set and the pointer to the message corresponding to the destination identifier is added to the message list for the particular wireless device performing method  50  (step  64 ). From step  64 , the method proceeds to step  66  wherein the search pointer is advanced to the next destination identifier. If, in step  62 , the destination identifier is not equal to the device identifier, the method  50  proceeds directly from step  62  to step  66 . After step  66 , the count of identifiers listed is decremented. The amount the count is decremented may be determined as desired. 
         [0023]    Referring now to  FIG. 5 , a method  70  for determining whether a message has arrived for a wireless device is shown. In this embodiment the devices are expecting more than one message with the same device identifier or multiple identifiers within the message listing. Multiple device identifiers for a single device may be used where the user of a particular device subscribes to several wireless multicast services, for example. By way of explanation, a device may have an identifier for messages specifically meant for the device and it may have another identifier assigned to it associated with a group of devices. In this way the entire group may be sent a message with only a single identifier being sent. A device may also be looking for some transmission broadcasted to an arbitrary number of devices such as, for example, sports game information or stock reports. 
         [0024]    The method  70  begins with step  72  wherein a search pointer to the first device identifier is initialized, the count of identifiers listed is loaded into the count variable, the flag and list messages are cleared, and a first test identifier from a test message list is loaded into a processing element of a wireless device. The test message list contains all of the identifiers that the device could potentially be receiving a message from during the time window is awakened to examine. The test list should be in a monotonic order suitable for searching the received identifiers. From step  72 , the method  70  proceeds to step  74  where it is determined whether the count of identifiers listed is equal to zero. If yes, the method  70  ends at step  76 . If no, the method  70  proceeds to step  78  wherein the destination identifier pointed to by the search pointer is loaded into a processing element of the device. Moving to step  80 , it is determined whether the destination identifier is greater than the test identifier. If yes, the method proceeds to step  82  where it is determined whether there is another test identifier in the test list. If there is another test identifier in the list, the next test identifier is loaded in step  84  and the method returns to step  74 . If there is not another test identifier, the method  70  ends at step  86 . 
         [0025]    Returning to step  80 , if the destination identifier is not greater than the test identifier, the method  70  proceeds to step  88 . In step  88 , it is determined whether the destination identifier is equal to the test identifier. If yes, a message flag is set and a pointer to the message corresponding to the destination identifier is added to the message list (step  90 ). From step  90 , the method  70  proceeds to step  92 . If, in contrast, the destination identifier is not equal to the test identifier, the method  70  proceeds directly to step  92 . In step  92 , the search pointer is advanced to the next destination identifier and in step  94  the count of identifiers listed is decremented. The amount the count is decremented may be determined as desired. 
         [0026]    Referring now to  FIG. 6 , there is shown an alternate embodiment of a message listing  100  in accordance with the present invention. In this embodiment there is not a count of the identifiers listed, but rather a list terminator  102  wherein the message listing is terminated by a unique number in the usual identifier position. 
         [0027]    An efficient value for this terminator in the increasing identifier implementation would be zero. In this way only the pointer needs to be changed during the search, and the comparison for an identifier larger than the one in the listing would terminate the search. 
         [0028]    A method whereby devices may determine whether a message listing as shown in  FIG. 6  includes any messages for them is shown if  FIG. 7 . The method  120  begins in step  122  with initializing a search pointer to the first destination identifier. In step  124 , the destination identifier pointed to by the search pointer is loaded into a processing element of the device. In step  126 , it is determined whether the destination identifier is equal to the termination value (i.e. the value of the list terminator). If the destination identifier is equal to the termination value, the method proceeds to step  128  where the message flag is cleared and the method  120  ends. If the destination identifier is not equal to the termination value, the method  120  proceeds to step  130  where it is determined whether the destination identifier is greater than the device identifier of the particular device that is determining whether a message listing contains a message for it. If the destination identifier is greater than the device identifier, the method  120  proceeds to step  128  where the message flag is cleared and the method  120  ends. If the destination identifier is less than or equal to the device identifier, the method  120  proceeds to step  132 . 
         [0029]    In step  132 , it is determined whether the destination identifier is equal to the device identifier. If so, the message flag is set and the pointer to the message that corresponds to the destination identifier is loaded into a processing element of the device (step  134 ). If not, the search pointer is advanced to the next destination identifier in step  136  and the method  120  continues at step  124 . 
         [0030]    Which of the preceding forms is used, or some variation of those presented, is based on efficiency tradeoffs associated with the numerical values allowed for the identifiers and message pointers, and the processing devices searching for messages. The pointer to the message can be a simple programming language pointer to the information defining the existence of the actual message transmission, or it may be the information itself. The actual information may be of the form: carrier channel, time slot, and channelization code. If the message information is very short (e.g. telephone number), it will often be more efficient to insert in the message in the usual position for the message pointer. In this case one or more bits of the message pointer part of the stream will need to be reserved as definition bits for the other bits present. Two bits, for instance, could be encoded such that one encoding indicates the rest of the bits is the message, another encoding that the pointer to the message follows, and a third encoding that the pointer to the data defining where to find the message follows. The fourth encoding possibility is a spare for some future use. 
         [0031]    With respect to implementation of the present invention in 3G Radio Access Networks, there are two basic methods for identifying “destinations” and “message pointers.” broadcast (BCCH over BCH/P-CCPCH) or dedicated (DCCH over DCH/DPCCH+DPDCH) signaling. If dedicated signaling is applied, the signaling is specific for the “destination,” and there is no application or benefit in ordering the control information since all of it is for the destination device. If broadcast signaling is applied, the existing mechanism that retrieves this data is independent of the processing of the data. 
         [0032]    When the number of messages is small, the above-described embodiments are usually the fastest means for locating or determining there is not a message for the device. However, if the list is long, there are faster methods which may be implemented to search a monotonically increasing or decreasing message list. For example, binary search protocols on average require log 2 (Count) tests. The calculations are more involved, and different processors will be able to perform them with varying speeds. Typically if there are more than approximately 32 received identifiers, binary searching will be faster for a single identifier being tested. If there are multiple identifiers being tested, sequential testing is more efficient for a larger count. The choice of protocol may also be chosen based on the values of the identifier or identifiers being tested. If a single number is being searched for is low and the receive sequence (i.e. message listing) monotonically increasing, the best approach is to begin the search at the beginning of the received data. If the signal number is high and the receive sequence monotonically increasing, the best approach is to begin the search at the end of the received data. (Data is often transmitted in wireless systems in blocks with interleaving for error correction reasons. All the data of a block therefore needs to be received and decoded before any of it can be examined.) Therefore, a preferred embodiment of the present invention is to take into account the number of received identifiers, whether or not there is one or more identifiers to be looked for, and the numeric distribution of the looked for identifiers in the selection of the search protocol utilized for each search occurrence. 
         [0033]    Referring now to  FIG. 8 , there is shown a system  200  for optimizing power resources in wireless devices. The system  200  comprises at least one radio network controller (RNC), at least one base station (BS), and at least one wireless device ( 206 ). The wireless device  206  includes a processor  208  for searching message listings for messages wherein the device  206  is the intended recipient. To maximize the amount of time that the device  206  may be asleep (i.e. having only the clock running which will tell the device to periodically wake-up), the message listings are adapted as described above. The device  206  will determine whether a particular message listing includes a message(s) for it using the methods described above according to the type of message listing. 
         [0034]    Although particular processing functions have been described as being performed by particular components, it should be understood that performance of processing functions may be distributed among system components as desired. 
         [0035]    Although the present invention has been described in detail, it is to be understood that the invention is not limited thereto, and that various changes can be made therein without departing from the spirit and scope of the invention, which is defined by the attached claims.