Title of Invention

SYSTEM AND METHOD FOR OPTIMIZING BATTERY USAGE OF A MOBILE STATION DURING LIMITED SERVICE

Abstract

In the existing mobile stations, there does not exist a mechanism to identify whether a mobile station is in a stationary condition that is non-mechanical and that does not consume much of battery power. The embodiments as disclosed achieve this by providing a mechanism to determine location condition using RSSI values of serving cell and at least one neighboring cell. A method and a mobile station are disclosed in accordance with various embodiments.

Full Text

FIELD OF THE INVENTION The invention is related to telecommunication systems and more particularly, the invention is related to identifying location condition of a mobile station (MS). DESCRIPTION OF RELATED ART When a MS looses coverage of the registered public land mobile network (PLMN), the MS searches for the available PLMNs for normal service. When there is no available PLMN for normal service, the MS searches for the PLMNs for camping for limited service. This is done in order to enable the user to avail the facility of making SOS calls in case of emergency. When MS is camped for limited service, registered network will not be aware of location of the MS. So, in such a case, a MS cannot receive any mobile-terminated (MT) call. The MS cannot make any mobile-oriented (MO) call in this state as well. In this state, the MS has to make periodic attempts to regain normal service. The periodicity of scanning for normal service should be chosen in such a way that MS should be able to regain normal service as soon as it is available and should not waste the battery doing the scan for normal service continuously. In order to avail normal service, MS has to search for a different PLMN than the currently camped on PLMN. When MS is camped and registered for normal service, user can make normal MO voice calls and also will be available for MT calls. If a MS is in a stationary condition for a longer duration of time where it failed to find any PLMN for normal service, it will be wasting battery if the MS does periodic scan for a PLMN providing normal service. There are methods proposed to optimize the scan for normal service based on location of the MS when camped for limited service. However, figuring out whether a MS is in stationary condition or not is done through mechanical means which is either an addition to the MS making the MS heavy and/or bulky and also could use more battery than required. For example, in GB2413737, the inventors disclose usage of passive motion detection devices such as non-mercury tilt switch and vibration detector. Hence there is a need for a method to identify whether a MS is in a stationary condition that is non-mechanical and that does not consume much of battery power. SUMMARY OF THE INVENTION In view of the foregoing, an embodiment herein provides a method of enhancing battery life in a MS in a telecommunication system, when a MS is camped for a limited service, the method comprising the steps of: identifying that MS is camped for a limited service; measuring RSSI values for serving cell and at least one neighboring cell; storing location information of said MS by storing global cell identities of said serving cell and said at least one neighboring cell and corresponding RSSI values of said cells; identifying new location information; comparing stored location information with new location information at periodic intervals; and resuming scan for available PLMNs for normal service only when at least one of new RSSI values of identified cells is greater than corresponding stored RSSI value by a pre-determined offset value 'd'. Furthermore, an embodiment herein provides an MS in a telecommunication system, adapted to enhance battery life when the MS is camped for a limited service, the MS comprising of: a location information gathering module to obtain RSSI and global cell identity values of said serving cell and said at least one neighboring cell; a memory to store said location information; a timer module to time location information gathering interval; and a comparator module to compare stored location information with new location information at periodic intervals. These and other aspects of the embodiments herein will be better appreciated and understood when considered in conjunction with the following description and the accompanying drawings. It should be understood, however, that the following descriptions, while indicating preferred embodiments and numerous specific details thereof, are given by way of illustration and not of limitation. Many changes and modifications may be made within the scope of the embodiments herein without departing from the spirit thereof, and the embodiments herein include all such modifications. BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS The embodiments herein will be better understood from the following detailed description with reference to the drawings, in which: FIG. 1, 1A and 1B shows an example cellular network structure; FIG. 2 illustrates an example mobile station in accordance with various embodiments as described herein; and FIG. 3 is a method in accordance with various embodiments as described herein. DETAILED DESCRIPTION OF THE INVENTION The embodiments herein and the various features and advantageous details thereof are explained more fully with reference to the non-limiting embodiments that are illustrated in the accompanying drawings and detailed in the following description. Descriptions of well-known components and processing techniques are omitted so as to not unnecessarily obscure the embodiments herein. The examples used herein are intended merely to facilitate an understanding of ways in which the embodiments herein may be practiced and to further enable those of skill in the art to practice the embodiments herein. Accordingly, the examples should not be construed as limiting the scope of the embodiments herein. As mentioned, there remains a need for a method to identify whether a MS is in a stationary condition that is non-mechanical and that does not consume much of battery power. The embodiments herein achieve this by providing a mechanism to determine location condition using RSSI values of serving cell and at least one neighboring cell. Referring now to the drawings, and more particularly to FIGS. 1 through 3, where similar reference characters denote corresponding features consistently throughout the figures, there are shown preferred embodiments. Now referring to FIGS. 1, 1A and 1B, the figure shows an example cellular network structure. Coverage area (commonly known as location area (LA)) of communications is divided into cells. Each cell has a base station (BS) to provide coverage for the cell in which it is located. A serving cell (SC) provides coverage for a mobile station (MS) within the cell and each of the adjacent one or more cells is referred to as a neighboring cell (NC). For example, a MS may be a mobile phone, a PDA, a communicator, or a portable computer that is capable of performing functions as described herein. A public land mobile network (PLMN) is a network that is established and operated by an operating agency like a telecommunications service provider for the specific purpose of providing land mobile telecommunications services to public. Typically, a PLMN consists of multiple location areas (LAs) as shown in FIG. 1A. Also, there could be multiple PLMNs operated by multiple agencies (like multiple telecommunications service providers) that overlap with each other as shown in FIG. 1B. The MS as per the invention may be implemented as shown in Fig 2. Here the transmitter/receiver module (204) is used to monitor the signal levels of all RF channels within its bands of operation. These signal levels are used in determining that the MS is camped for a limited service. The method of determining that the MS is camped for limited service based on the signal levels is well known. 3GPP TS 03.22 gives an example method for idle mode operation. Section 6.8 of 3GPP TS 05.08 gives an example to determine that the MS is camped for limited service. When in limited service state, the MS shall monitor the received signal level of all the RF channels within its band of operations and search for a BCCH carrier with a positive path loss criterion. When such a cell is found, the MS camps on that cell. When an MS is camped for limited service, then the MS determines the RSSI values for the serving cell and neighboring cells. The RSSI value for a cell is determined by taking an average of the signal levels for each of the channels over a period of time. The process for doing this is also well known. For example 3GPP TS 05.08 gives a method for determining the RSSI values. Here RSSI values are given as a running average of received signal level (RLA_C) in the preceding 5 to Max {5 , ((5 * N + 6) DIV 7) * BS_PA_MFRMS / 4} seconds. N is the number of non-serving cell BCCH carriers in BA and the parameter BS_PA_MFRMS is defined in 3GPP TS 05.02. The same number of measurement samples shall be taken for all non-serving cell BCCH carriers of the BA list, and the samples allocated to each carrier shall as far as possible be uniformly distributed over each evaluation period. At least 5 received signal level measurement samples are required per RLA_C value. New sets of RLA_C values shall be calculated as often as possible. However, there remains a need for a method to identify whether a MS is in a stationary condition that is non-mechanical and that does not consume much of battery power. The embodiments herein achieve this by providing a mechanism to determine location condition using RSSI values of serving cell and at least one neighboring cell that are calculated by the known methods as referred to herein above. Location Information gathering module (206) gathers and stores global cell identities of the serving cell and the neighboring cells that are within the access of the MS. Memory (208) is used to store the the gathered RSSI values & the global cell identities of the serving cells and at least one neighboring cell. For example, memory could be any suitable volatile or non-volatile memory component. The Timer module (202) periodically checks for changes in the RSSI values. The Comparator module (210) is used to check the difference between the new RSSI values and the stored RSSI values. When at least one of new RSSI values of identified cells is greater than corresponding stored RSSI value by a pre-determined offset value 'd', network scan is resumed. In some embodiments, network scan is resumed when at least one new RSSI value is greater than corresponding stored RSSI value by the pre-determined offset value 'd'. In other embodiments, network scan is resumed when all new RSSI values are greater than corresponding stored RSSI values by the pre-determined offset value 'd'. The embodiments herein can take the form of an entirely hardware embodiment including hardware components but not limited to processors, micro controllers, digital signal processors (DSP) and any combination of these components, an entirely software embodiment or an embodiment including both hardware and software elements. The embodiments that are implemented in software include but are not limited to, firmware, resident software, microcode, etc. The method of enhancing the battery life in a MS telecommunication system, when a MS is camped for limited service can be implemented as shown in Fig 3 in accordance with various embodiments as described herein. We first determine that a MS is camped for limited service based on known methods using the monitored signal levels of the serving cell and the neighboring cells or any other suitable method. Once we determine that a MS is camped for limited service it is in the state represented by 302. Further, RSSI values for the serving cell and the neighboring cells are gathered. These are store in memory, the memory being either a volatile or a non-volatile memory in accordance with various embodiments as described herein. Furthermore, the global cell identities of the serving cell and the neighboring cells are gathered. These identities are also stored in said memory. Together the RSSI values & the global cell identities determine the location information for a MS as shown in 304. Then MS goes into drx mode where the MS measures the serving cell and the neighboring cells periodically. When the limited service timer expires at 308, it is checked if there is a change in location at 310. Change in location is determined by checking the RSSI values for the serving cell and the neighboring cells. In some embodiments, when at least one of new RSSI values of identified cells is greater than corresponding stored RSSI value by a pre-determined offset value 'd', there is a change in location. In some other embodiments, when all new RSSI values of identified cells are greater than corresponding stored RSSI values by a predetermined offset value 'd', there is a change in location. If the location is stationary the system goes back to drx mode at 306 and waits for the limited service timer at 308. If the location has changed then a rescan of networks for normal service is initiated at 314. If MS does not find normal service and is still camped in limited service, MS goes back to the initial state at 302 and the method is repeated. The foregoing description of the specific embodiments will so fully reveal the general nature of the embodiments herein that others can, by applying current knowledge, readily modify and/or adapt for various applications such specific embodiments without departing from the generic concept, and, therefore, such adaptations and modifications should and are intended to be comprehended within the meaning and range of equivalents of the disclosed embodiments. It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation. Therefore, while the embodiments herein have been described in terms of preferred embodiments, those skilled in the art will recognize that the embodiments herein can be practiced with modification within the spirit and scope of the appended claims. We Claim 1. A method of enhancing battery life in a MS in a telecommunication system, when a MS is camped for a limited service, the method comprising the steps of: a) identifying that MS is camped for a limited service; b) measuring RSSI values for serving cell and at least one neighboring cell; c) storing location information of said MS by storing global cell identities of said serving cell and said at least one neighboring cell and corresponding RSSI values of said cells; d) identifying new location information; e) comparing stored location information with new location information at periodic intervals; and f) resuming scan for available PLMNs for normal service only when at least one of new RSSI values of identified cells is greater than corresponding stored RSSI value by a pre-determined offset value 'd2. 2. A method as in claim 1, the method further comprising the step of updating stored location information with new location information when all new RSSI values are greater than corresponding stored RSSI values by said pre-determined offset value 'd'. 3. A MS in a telecommunication system, adapted to enhance battery life when the MS is camped for a limited service, the MS comprising of: a) a location information gathering module to obtain RSSI and global cell identity values of said serving cell and said at least one neighboring cell; b) a memory to store said location information; c) a timer module to time location information gathering interval; and d) a comparator module to compare stored location information with new location information at periodic intervals. 4. A MS as in claim 3, where memory is a non-volatile memory. 5. A MS as in claim 3, where memory is a volatile memory.

Documents:

2751-CHE-2007 EXAMINATION REPORT REPLY RECEIVED 09-07-2014.pdf

2751-CHE-2007 FORM-1 09-07-2014.pdf

2751-CHE-2007 OTHER PATENT DOCUMENT 09-07-2014.pdf

2751-CHE-2007 POWER OF ATTORNEY 09-07-2014.pdf

2751-CHE-2007 ABSTRACT.pdf

2751-CHE-2007 AMENDED PAGES OF SPECIFICATION 09-07-2014.pdf

2751-CHE-2007 AMENDED CLAIMS 09-07-2014.pdf

2751-CHE-2007 CLAIMS.pdf

2751-CHE-2007 CORRESPONDENCE OTHERS.pdf

2751-CHE-2007 DESCRIPTION (COMPLETE).pdf

2751-CHE-2007 DRAWINGS.pdf

2751-CHE-2007 FORM-1.pdf

2751-CHE-2007 FORM-13 13-12-2013.pdf

2751-CHE-2007 FORM-18.pdf

2751-CHE-2007 FORM-13 16-12-2013.pdf