MXPA04007544A

MXPA04007544A - Method and apparatus for efficient selection and acquisition of a wireless communications system.

Info

Publication number: MXPA04007544A
Application number: MXPA04007544A
Authority: MX
Inventors: Cooper Rotem
Original assignee: Qualcomm Inc
Priority date: 2002-02-05
Filing date: 2003-02-05
Publication date: 2004-11-10
Also published as: RU2004126674A; WO2003067918A1; EP1472899A1; AU2003219717A1; KR20040077931A; CN1628482A; JP2006504291A; BR0307440A; CA2474506A1

Abstract

A mobile station includes processing circuitry and a memory. A group of wireless communications systems is selected in accordance with a predetermined system acquisition procedure. A received signal corresponding to each selected system is analyzed to determine a likelihood that the selected system would be acquired by the mobile station. The group of selected systems is reprioritized based on the results of the analysis to produce a more efficient system acquisition sequence. The mobile station then attempts to acquire a selected wireless communications system in accordance with the system acquisition sequence.

Description

METHOD AND APPARATUS FOR SELECTION AND EFFICIENT ACQUISITION OF A WIRELESS COMMUNICATIONS SYSTEM Field of the Invention The present invention relates generally to wireless communications, and, in particular, to a method and apparatus for efficiently selecting and acquiring a wireless communication system.

BACKGROUND OF THE INVENTION A mobile device will often have access to more than one wireless communication system in its geographic region. The quality of the wireless services available to the mobile device may vary from system to system depending on the equipment used by each system, the characteristics of the mobile device, the distance between the mobile device and the local base stations, physical obstructions such as buildings and hills. and the volume of communications traffic in each system. Communications systems can also support different protocols for multiple access wireless communications such as code division multiple access (CDMA), broadband CDMA (WCD A), and Advanced Mobile Telephony Service (AMPS), Global Communications System Mobile (GSM), General Package Radio Services (GPRS) or High Data Rate (HDR) technology (for example, lxEV technology). In addition, the fees charged to a user of the mobile device may vary depending on the time of day, the duration of the connection to the wireless communication system and in addition the mobile device is listed as a subscriber of the wireless communication system. To assist with the selection of a desirable wireless communications system, conventional mobile devices store data describing known systems in a preferred roaming list (PRL). The PRL usually includes a table of systems that stores a system identifier (SID) and a network identifier (NID) for each known wireless communications system, and an acquisition table that stores acquisition parameters including band, frequency and mode, for the known wireless communications systems. Within the systems of the table, wireless communication systems are often grouped by geographic region and are classified from the most desirable to the least desirable system in each region. The most desirable system in a particular geographic region is usually a subscriber system, but it can also be a roaming system that offers the mobile device a favorable combination of low cost and high quality of service. Roaming systems offer wireless services to unsubscribed mobile devices, usually at a much higher rate than subscription services, and may be desirable when the mobile device accesses a geographic region that is outside the coverage area of the subscription service of the mobile device, when subscription services are blocked or otherwise unavailable, or when subscription services are only available at an unacceptably low level of quality. During a power-on sequence of the mobile device, attempts are made to acquire and register with the most desirable wireless communication system that is available to the mobile device in its current geographical region. In one approach, the mobile device identifies its current geographic region and then takes a step through the entries in the systems table, from the most desirable system in the geographic region identified in the least desirable system in the identified geographic region, until an attempt to register and acquire the system is successful. The mobile device may also attempt to acquire and register through a new wireless communication system during the operation. For example, The connection between the mobile device and a current wireless communications system may be lost, requiring the acquisition of a new system by the mobile device. In addition, the wireless communication systems that are available to the mobile device may change as the position of the mobile device and its surrounding environmental changes. To provide the user of the mobile device with the best combination of high quality and low cost, many mobile devices periodically attempt to acquire and register with a wireless communication system that is more desirable than the current wireless communication system used by the mobile device. The mobile device investigates the table of systems for wireless communication systems in its geographical region which is more desirable than the current system used by the mobile device and if more desirable systems are found in the system table, the mobile device will be interrupted outside the current communications channel and will try to acquire and register through one of the most desirable systems. A system acquisition sequence, such as the system acquisition sequences described above, will often include a series of failed attempts to acquire a signal and register it with the corresponding wireless communications system, followed by a single successful system of acquisition and registration. . A preferred roaming list usually includes more than 50 systems and under certain conditions the mobile device can spend more than 60 seconds advancing through the systems in the preferred roaming list before an acquisition attempt is successful. These failed acquisition attempts are common and can be triggered by a variety of factors. For example, the mobile device may be unable to detect a pilot signal transmitted from a base station of the system if the pilot signal is blocked or weakened by physical obstructions, or if the mobile device is outside the coverage area of the base station . Registration with the system may fail if the mobile device and the system use incompatible protocol revisions and hardware, or if the system otherwise rejects the registration attempt of the mobile device. In view of the above, there is a need in the art for a method and apparatus for efficiently selecting and acquiring a wireless communication system.

SUMMARY OF THE INVENTION The present invention is a method and apparatus for effectively selecting and acquiring a wireless communication system. In a preferred embodiment, a mobile station selects a group of wireless communication systems according to a predetermined system acquisition procedure. The selected group of systems has a priority order, such as an order of preference determined by a wireless service provider, which can be used by the mobile station during attempts to acquire and register the system. Then, the reception of signals corresponding to each of the selected systems is analyzed to determine the probability that each of the corresponding systems would acquire by the mobile station. The group of wireless communications systems is re-prioritized based on the results of the analysis to produce a more efficient system acquisition order. The mobile station attempts to acquire and register with one of the systems in the re-prioritized group of wireless communication systems according to the order of acquisition specified by the group.

The mobile station preferably includes processing circuitry, a memory, a communication transceiver and an antenna. The processing circuitry includes a control processor for controlling the operation of the mobile station, a signal processor, a searcher and a system determination unit. In a preferred embodiment, the mobile station is a multi-mode device and the processing circuitry is adapted to be operated in any CDMA or AMPS mode. The memory preferably includes both volatile and non-volatile random access memories that store a preferred roaming list, including a system table and an acquisition table, and one or more look-up tables such as a candidate list. The system determination unit is adapted to select one or more wireless communication systems from the system table according to a system acquisition procedure. In a preferred embodiment, the system determination unit stores the selected systems in the candidate list and instructs the search engine to analyze a received signal corresponding to each of the systems in the candidate list. For each listed system, the browser instructs the transceiver to interrupt the corresponding channel of the system and a received signal is analyzed. The analysis of the received signals can include measuring the received signal strength (Rx) of each system, measuring the signal at noise ratio Ec / I0 (or other tests that help determine if the candidate system is likely to be acquired, condition that the test requires less time than an attempt to acquire and record the complete system After each system is analyzed, the group of selected systems is re-prioritized based on the results of the analysis. all systems are classified so that those systems that have the highest probability of being acquired are selected first In a first alternative mode, the order of convenience is maintained and, at each level of convenience, the selected systems are classified using the results of the analysis In a second alternative modality, the information of convenience for each selected system is adjusted based on the The results of the analysis and the group of selected systems are then classified using the adjusted convenience information. In a third alternative mode, each system that has a corresponding analysis result that is lower than a threshold value is removed from the group of selected systems. The mobile station immediately tries to acquire and register with a wireless communication system. The system that has the highest level of priority is first selected from the re-prioritized candidate list and an attempt is made to acquire and register with the selected system. Any system acquisition method can be used including conventional system acquisition methods that are well known in the art. If the acquisition / registration attempt is not successful, then the wireless communication system having the next highest priority is selected from the candidate list and another acquisition / registration is attempted. This process continues until an attempt to acquire / register the system is successful, or until there are no additional candidate systems. In a preferred embodiment, if the acquisition / registration attempt is successful, the wireless communication system is used for future wireless communications services. In an alternative embodiment, the acquired wireless communications system has a known geographical region and an attempt is made to acquire and register with a more preferred wireless communication system in the geographic region. In a first sequence of acquiring the alternative system, a first system is selected according to a system acquisition procedure. Any method of acquiring the system can be used, including the selection of the system that was most recently used by the mobile station. The signal quality of the selected system is measured and if the system is not likely to be acquired, then the following system is selected according to the system acquisition procedure. If a selected system is likely to be acquired then an attempt is made to acquire and register with the selected system. If the acquisition / registration attempt is successful then the wireless communication system is used for future wireless communications services. Otherwise, the following system is selected according to the system acquisition procedure. A more complete understanding of the Method and Apparatus for Efficient Selection and Acquisition of a Wireless Communications System will be produced by those skilled in the art, as well as an embodiment of additional advantages and objects thereof, for a consideration of the following detailed description of modalities. preferred. Reference will be made to the appended sheets of the drawings, which will be briefly described first.

BRIEF DESCRIPTION OF THE DRAWINGS The characteristics, objects and advantages of the present invention will become more apparent from the detailed description set forth later when taken together with the drawings in which similar reference characters are correspondingly identified completely and where : Figure 1 illustrates a preferred embodiment of the present invention; Figure 2 is a mobile station according to a preferred embodiment of the present invention; Figure 3a is a table of systems according to a preferred embodiment of the present invention; Figure 3b is an acquisition table according to a preferred embodiment of the present invention; Figure 4 illustrates preferred look up tables used by the mobile station according to a preferred embodiment of the present invention; Figure 5 is a flow chart illustrating a preferred system selection and acquisition procedure; and Figure 6 is a flowchart illustrating a method of selecting and acquiring the alternative system.

DETAILED DESCRIPTION OF THE INVENTION A preferred embodiment of the present invention will now be described with reference to Figure 1. A mobile station 2 operates in a geographic region 4 serving by at least one base station 6. Each base station 6 is connected to a network 8, which is part of a larger wireless communication system that supports at least one wireless protocol of multiple access, such as code division multiple access (CDMA), CDMA broadband (CDMA), Advanced Mobile Telephony Service (AMPS), Global System for Mobile Communications (GSM), General Packet Radio Services (GPRS), or High Data Rate (HDR) technology (for example, lxEV technology) . The mobile station 2 can be any wireless device, either stationary or mobile, which is adapted for wireless communications with at least one base station 6, such as cellular telephony, paging, personal digital assistance (PDA), vehicular navigation system or computer laptop . In a preferred embodiment, the mobile station is a multi-mode device that is adapted to operate in both CDMA and AMPS modes. The mobile station 2 includes a list of known wireless communications systems, such as a preferred roaming list (PRL). The PRL 10 is stored in a non-volatile memory of the mobile station 2 and includes a list of wireless communication systems and corresponding acquisition parameters that are used by the mobile station 2 during attempts to acquire and register with a wireless communication system. In a preferred embodiment, the wireless communication systems listed in the PRL 10 are grouped by geographic region and classify the most desirable to least desirable system in each region. As is known in the art the PRL 10 can be maintained by the wireless service provider of the mobile station and includes a list of wireless communication systems that are available in the mobile station 2 through its wireless service provider or other wireless providers. wireless service that have agreed to provide roaming services to mobile station 2. In operation, the mobile station 2 attempts to acquire and register with an available wireless communication system that offers wireless services to the mobile station 2. First, a group of wireless communication systems is selected from the PRL 10 according to a predetermined system acquisition procedure. The group of systems has a priority order that can be used by the mobile station 2 during attempts to acquire and register the system. For example, in a preferred embodiment, the wireless communication systems in the geographical region 4 of the mobile station are selected and classified from the most desirable to least desirable system in each region. After, the received signals corresponding to each of the selected systems are analyzed to determine a relative probability that each of the corresponding systems would acquire by the mobile station 2. The group of wireless communication systems is then re-prioritized based on the results of the analysis to produce a more efficient system acquisition order. The mobile station 2 selects the system from the reprioritized group which has the highest relative priority and attempts to acquire and register with the selected system. If the acquisition / registration attempt is successful, the selected system is used by the mobile station 2 for wireless communications. Otherwise, an attempt is made to acquire / register with the system from the group that has the next highest priority. With reference to Figure 2, a preferred embodiment of the mobile station 2 will now be described. The mobile station 2 includes processing circuitry 80, a memory 82, a communication transceiver 84 and an antenna 86. The processing circuitry 80 preferably includes a control processor 90 for controlling the operation of the mobile station 2, a processor 92 of signal, a searcher 94 and a system determination unit 96. The memory 82 preferably includes both volatile and non-volatile random access memories that store a preferred roaming list, including a system table 100 and an acquisition table 102. The memory 82 may also store one or more look-up tables, such as a list of the most recently used systems 106, and program instructions for execution by the processing circuitry 80.

The searcher 94 is adapted to identify valid signals, such as pilot signals, synchronization channels and search channels received by the transceiver 84 through the antenna 86. The design and implementation of the hardware searcher for CDMA acquisition is described in the Patent. No. 5,109,390, entitled "RECEIVING DIVERSITY IN A CDMA CELLULAR TELEPHONE SYSTEM", assigned to the assignee of the present invention, and is incorporated herein by reference. The search engine 94 is adapted to perform a primary acquisition analysis of one or more candidate communication systems. The system determination unit 96 is adapted to select one or more wireless communication systems from the system table 100 and retrieve the corresponding acquisition parameters from the acquisition table 102. The system determination unit 96 is further adapted to send the acquisition parameters to the searcher 94, which attempts to acquire the selected systems. In an alternative embodiment, the system determination unit 96 determines whether the current wireless communication system is the most desirable system in the current geographic region of the mobile device and, when the most desirable systems are available, initiate the attempts by the mobile station 2. mobile to acquire a more desirable system. A method and apparatus for selecting the preferred system in a mobile station that is capable of operating in a plurality of geographic regions is described in US Patent No. 6,085,085, entitled "METHOD AND APPARATUS FOR PERFORMING SELECTION OF THE PREFERRED SYSTEM", assigned to the assignee, and is incorporated herein by reference. It should be appreciated that the mobile station 2 illustrated in Figure 2 is merely illustrative and that alternative configurations and additional features are contemplated within the scope and spirit of the present invention. For example, the components of the mobile station 2 can be implemented in numerous hardware configurations using conventional circuit elements such as one or more processors, memories and application-specific integrated circuits (ASICs). The mobile station 2 can also be adapted for voice communications, high-speed data communications, video communications, internet applications such as e-mail and HTML World Document Network access, location location (for example, gpsOne ™ developed by the transferee), personal navigation, voice recognition, integrated removable storage devices and short-range wireless connectivity with peripheral components and local devices. In one embodiment, the processing circuitry 80 includes a mobile station MODEM chip set, developed by the transferee, which integrates digital and analog functions together with the location location based on GPS. With reference to Figures 2 and 3a, a preferred embodiment of the system table 100 will now be described. The system table 100 includes a list of wireless communication systems that the mobile station 2 used during attempts to acquire and register with a wireless communication system. As illustrated, each record in the system table 100 preferably includes a system identifier 100a (SID), a network identifier 100b (NID), an indication of whether the system is preferred or negative (P / N) 100c, a The geographic region (region) identifier is covered by the system, convenience information, and a lOOf indicator (AT indicator) in a record in an acquisition table 102. Each wireless communication system listed in the system table 100 is identified through a unique SID 100a, NID pair 100b and is designated as any preferred system that can be used for mobile station 2 during roaming or a negative system that does not it must be used by the mobile device 2 during roaming through the P / N 100c. In the alternative modalities, the wireless communication systems listed in table 100 of systems can be identified using other system identifiers, such as a single band, mode and frequency, and Version 6 of the Internet Protocol (IPV6) addressed or an identifier of Land Mobile Network Public (PLMM). The wireless communication systems are preferably grouped by geographical region and are stored in the system table 100 in order from the most desirable system to the least desirable system in each region using the convenience information. With reference to Figure 3b, a preferred embodiment of the acquisition table 102 will now be described. The acquisition table 102 includes a list of parameters that are necessary for the acquisition of wireless communication systems listed in the system table 100. As illustrated, each record in the acquisition table 102 preferably includes a mode 102a, a band 102b and a frequency 102c. The system table 100 and the acquisition table 102 are preferably stored in a non-volatile memory and are periodically updated by an external source, such as the mobile service provider of the mobile station, through downloads over a wireless connection or through another method of data transfer. It will be appreciated that the alternative configurations for the PRL, the system table 100 and the acquisition table 102, and the alternative identification and acquisition parameters can be used in accordance with the present invention. As illustrated in Figure 4, the memory also includes one or more query tables 104. In a preferred embodiment, the lookup tables include a most recently used system table 104a (MRU) that stores a list of most recently used systems by the mobile station 2, a list 104b of candidates that includes a list of systems that have been selected as candidates for acquisition, and a preference table 104c that maintains local preference parameters for mobile station 2. Other information can also be stored in a look-up table including historical information that tracks the use of each system. Query tables are preferably stored in a volatile portion of memory 24, but in alternative embodiments, one or more look-up tables may be stored in a non-volatile portion of memory 24. A preferred system acquisition sequence for the station 2 mobile will now be described with reference to Figure 2 and the flow chart of Figure 5. The acquisition sequence of the system is preferably performed by the system determination unit 96. In Step 200, a group of wireless communication systems is selected from a stored list of systems according to a predetermined system acquisition procedure. In a preferred embodiment, the wireless communication systems in the geographical region 4 of the mobile station are selected from the system table 100, and the corresponding system identifiers are stored in the candidate list 104b in the memory 24. In the modalities alternatives the candidate list 104b may include other data such as the corresponding acquisition parameters and convenience information for the selected systems. The candidate list 104b is preferably classified in an initial order of priority (eg, from the most desirable system to the least desirable system) as determined by the predetermined system acquisition procedure. Although the selection of the system using a PRL is illustrated, it will be appreciated that the other methods of acquiring the system may be used in accordance with the preferred embodiment of the present invention. For example, in alternative embodiments, the method of acquiring the system may include selecting a group of systems from MRU 104a or other lists of stored systems. As is known in the art, system table 100 specifies a preferred system acquisition order for use by mobile station 2 during system acquisition / registration attempts. This system acquisition order, however, is not always the most efficient section order of the system to acquire and register with a wireless communication system. The selection order specified for the system table 100 is normally determined by the wireless service provider of the mobile station based on factors that are not related to the probability that each of the listed systems will be acquired by the mobile station 2. For example, the convenience of each system can be determined using criteria such as the cost to use the system, the quality of the communication service offered by the system, the protocol used by the system, support for unique features, and whether the mobile station 2 list as a subscriber of the wireless communications system. To improve the efficiency of the system acquisition / registration process, the mobile station 2 analyzes a received signal corresponding to each of the systems in candidate list 104b (Stage 202) and adjusts the system acquisition order based on the results of the analysis (Stage 204). In a first embodiment, the analysis of the received signals includes measuring the received signal strength (Rx) of each system. In operation, the browser 94 advances through the systems identified in the candidate list 104b stored in the memory 24. In the alternative mode, the candidate list can be transmitted to the browser 94 from the system determination unit 96. For each listed system, the browser 94 instructs the transceiver 84 to interrupt the corresponding channel of the system. The received signal resistance is then measured and stored in candidate list 104b. If the received signal resistance measurement is relatively low, there would be a low probability that the candidate system would be available for acquisition. If the measurement of received signal strength is relatively high, there would be a greater likelihood that the candidate system could be acquired. It will be appreciated that signal strength measurements for a group of systems can usually be completed significantly in less time than an attempt to acquire and register with each system in the group. In alternative modalities, other tests that help determine if the candidate system is likely to be acquired can be done on the signals received. In a first alternative embodiment, the analysis of the received signals includes determining whether the received signal is likely to be a CDMA signal. In this embodiment, the system determination unit 96 instructs the searcher 94 to measure the signal at the noise ratio Ec / lQ where Eq is the resistance of the received signal and I0 is the total thermal noise received in the channel. In a CDMA system, this measure provides an indication of the portion of the received signal that is usable. If the Ec / I0 ratio is relatively large, then there is a high probability that the system could be acquired. The Ec / lD ratio provides a more reliable indication of whether the signal is more likely to be acquired than the measured natural resistance of the signal. In a second alternative embodiment, the system determination unit 96 and the searcher 94 support the multiple acquisition test modes and methods, and can be adapted to use more than one type of analysis, alone or in combination. The test mode can be determined by the user's preference, configuration of the mobile station, current operating status of the mobile station or other criteria. The searcher 94 preferably operates in accordance with the instructions received from the system determination unit 96 and the system determination unit 96 is adapted to transmit a candidate system test instruction and a system acquisition instruction. The candidate systems test instruction includes parameters to identify the candidate list, an identifier of the test that will be carried out in each candidate system and a minimum threshold value that will be fulfilled for each system. The search engine 94 executes the received instruction and returns to the candidate systems that meet the test requirements. In a preferred embodiment, the browser 94 modifies the list of candidates stored in the memory. The system determination unit 96 is further adapted to analyze the test results and transmit a system acquisition instruction to the searcher 94, including parameters that identify the candidate lists.

In Step 204, the group of selected systems is re-prioritized based on the analysis to produce a more efficient system acquisition order. In a preferred embodiment, all systems are classified so that those systems that have the highest probability of being acquired are selected first. In a first alternative embodiment, a plurality of selected systems has the same level of convenience. At each level of convenience, the selected systems are classified using measured signal strength, from the most likely system to be acquired to the least likely system to be acquired. In a second alternative mode, the convenience information for each selected system is adjusted based on the test measurement. For example, the relative convenience of systems having a signal strength measurement greater than a first threshold value may be adjusted upward, while the relative convenience of systems having a signal strength lower than a second threshold value may be adjusted. adjust down. The group of selected systems is then classified using the adjusted convenience information. In a third alternative mode, systems that have a proven signal quality that is lower than a threshold value are removed from the group of selected systems. For example, candidate systems having a corresponding measured signal strength lower than -90db can be eliminated from the candidate list. Other criteria can also be used to eliminate and classify candidate systems. For example, a load factor can be used which takes into account the measured signal strength, if the system was recently used, the convenience evaluation and other information. After the group of selected systems is re-prioritized, the mobile station 2 attempts to acquire and register with one of the wireless communication systems in the group. In Step 206, the system having the highest level of priority is selected from candidate list 104b. In a preferred embodiment, this system has a relatively high level of convenience and a high probability so that the acquisition / registration attempt will be successful based on the measured signal quality such as a measure of signal strength. An attempt is made to acquire and register with the system selected in Step 208. Any method of acquiring the system can be used including conventional system acquisition methods that are well known in the art. In a preferred embodiment, the mobile station 2 is adapted to acquire a CDMA system. In order to acquire a CDMA system, the browser 94 instructs the transceiver 84 to interrupt the communication channel of the selected CDMA system and listens to a pilot signal. The searcher 94 attempts to verify the received pilot signal by testing several pseudo-random noise (PN) shifts in the received signal until an equivalence is found. When the signal is acquired, the processing circuitry 80 receives information for the forward CDMA channel and a phase reference for the signal demodulation. Then, the processing circuitry 80 attempts to acquire the synchronization channel associated with the identified pilot channel. The synchronization channel transmits basic system information such as the unique SID / NID of the transmission system and wireless communication network, and synchronization information. The processing circuitry 80 adjusts its time according to the received information and then switches the search channel of the base station. The search channel is used by a local base station of the current communication system to communicate with the mobile station 2 when the mobile station 2 is not assigned to the traffic channel. Through the search channel, the base station notifies the mobile station 2 of incoming messages, such as in incoming telephony calls or notification of a received voice mail message. If the acquisition / registration attempt is successful (Step 210) then the selected system is used by the mobile station 2 for wireless communications. If the acquisition / registration attempt is unsuccessful, the wireless communication system having the next highest priority is selected from the list of candidates in Step 212 and the control returns to Step 208 for the acquisition attempt / next record. If the searcher 94 is unable to acquire the selected system (Step 210) the searcher 94 will attempt to acquire each of the remaining systems according to the selection order until a wireless communication system is acquired or the candidate systems are exhausted. In an alternative embodiment, if the acquisition / registration attempt is successful in Step 210, then the process returns to Step 200 for the selection of a group of systems in the current geographic region that are more desirable than the selected system. An alternative system acquisition sequence is illustrated in the flow chart of Figure 6. In Step 250, a first system is selected according to a system acquisition procedure. Any procedure for acquiring the system can be used, including selecting the system that was most recently used by mobile station 2. The signal quality of the selected system is measured in Step 252. If the system is likely to be acquired (Step 254) then an attempt is made to acquire and register with the system selected in Step 256. In a preferred embodiment, the system it is likely to be acquired if the measured signal quality exceeds a predetermined threshold value. If the system is not likely to be acquired, then the following system is selected according to the system acquisition procedure in Step 260. If the acquisition / registration attempt is successful (Step 258) then the mobile station 2 uses the selected system for future wireless communications services. If the acquisition / registration attempt is unsuccessful, then the next wireless communication system is selected in Step 260 and the control returns to Step 252. Having thus described a preferred embodiment of the Method and Apparatus for Efficient Selection and Acquisition of a Wireless communication system, it should be evident by those skilled in the art that certain advantages within the described system have been achieved. It will also be appreciated that various modifications, adaptations and alternative embodiments thereof may be made within the scope and spirit of the present invention. The scope of the present invention is defined by the following claims.

Claims

NOVELTY OF THE INVENTION Having described the present invention, it is considered as a novelty and therefore what is described in the following claims is claimed as property. CLAIMS 1. In a mobile station that stores a list of wireless communication systems, a system acquisition procedure is characterized in that it comprises the steps of: selecting a group of wireless communication systems from the list according to the procedure of acquisition of the default system, the group of wireless communication systems has a first order of system acquisition; measure a signal quality for each of the selected systems; re-prioritize the group of wireless communication systems according to the measured signal quality, the re-prioritized group of wireless communication systems that has a second order of system acquisition; and try to acquire the wireless communication system that has the highest priority according to the second order of acquisition of the system. The method according to claim 1, characterized in that the list of wireless communication systems is a preferred roaming list that includes a geographic region identifier and the step of selecting a group of wireless communication systems that includes determining a region current geographic location of the mobile station and select the wireless communication systems listed having a geographical region identifier corresponding to the current geographical region of the mobile station, and wherein the first order of acquisition of the system is based on the relative order of the wireless communications systems selected in the preferred roaming list. The method according to claim 2, characterized in that each wireless communication system identified in the preferred roaming list has a corresponding level of convenience, at least two of the selected systems share the same level of convenience, and wherein the The re-prioritize stage includes locating selected systems that share the same level of convenience and classify the systems located by the measured signal strength. 4. The method according to claim 3, characterized in that each wireless communication system identified in the preferred roaming list has a corresponding level of convenience and the re-prioritizing step comprises the steps of: for each selected level adjust the level of corresponding convenience based on the corresponding measured signal strength, the convenience criterion adjustment is stored in the group of wireless communication systems; and classify the group of wireless communication systems by adjusting the levels of convenience. The method according to claim 1, characterized in that the re-prioritizing step comprises removing a selected system from the group if its corresponding measured signal quality fails to meet a minimum threshold. 6. The method according to claim 1, characterized in that the step of measuring a signal quality includes calculating an Ec / I0 ratio of the received signal. 7. A mobile station, characterized in that it comprises: a memory that stores a preferred roaming list, the preferred roaming list includes a first plurality of corresponding system identifiers and acquisition parameters; and processing circuitry adapted to select wireless communication systems from the preferred roaming list according to a predetermined system acquisition procedure, the selected wireless communication systems have a corresponding system acquisition order, wherein the circuitry Processing is further adapted to measure a signal quality of each selected system and modifies the order of acquisition of the system based on the measured signal qualities, the order of acquisition of the modified system that increases the efficiency of the system acquisition process. The mobile station according to claim 7, characterized in that the wireless communication systems selected include corresponding convenience criteria, and wherein the processing circuitry is further adapted to adjust the corresponding convenience criteria of a selected system if the measurement of corresponding signal strength exceeds a first threshold, and classifies the selected wireless communications systems using the adjusted convenience criteria. The mobile station according to claim 7, characterized in that the signal quality measured for each system includes a signal to noise ratio of the received signal, the signal to noise ratio corresponding to a probability that the corresponding system be acquired. 10. In a multiple mode mobile station adapted to operate in CDMA and AMPS modes, a method for acquiring a wireless communication system characterized in that it comprises the steps of: analyzing a received signal on a channel associated with a candidate communications system; determining, based on the analysis of the received signal, whether the candidate communications system is likely to be available for acquisition by the mobile station; and attempt to acquire the candidate communications system only if the candidate communications system is likely to be available for acquisition. The method according to claim 10, characterized in that the step of analyzing comprises interrupting a channel associated with the candidate communication system and testing a signal quality of the received signal. The method according to claim 11, characterized in that the mobile station includes a table of known communication systems, each known communication system has a relative convenience, and wherein the candidate communication system is selected from the system table of known communications according to a procedure for acquiring the predetermined system. The method according to claim 11, characterized in that the signal quality tested is a measure of received signal strength. 1 . The method according to claim 11, characterized in that the signal quality tested is a signal-to-noise ratio of the received signal. 15. The method according to claim 11, characterized in that the candidate communications system is likely to be available if the measured signal quality exceeds a predetermined threshold value. The method according to claim 11, further characterized in that it comprises the step of selecting a set of candidate communication systems, wherein the stages of analyzing and determining are repeated for each candidate communications system in the set and the stage of Attempt is made for the candidate communications system that is most likely to be acquired. The method according to claim 16, further characterized in that it comprises the step of classifying the candidate communication systems in order of the measured signal quality, the classified order defining an acquisition order for the set of candidate communication systems . 18. In a wireless device, an integrated circuit is characterized in that it comprises: a system determining unit adapted to identify the candidate communication systems in a current geographic region of the wireless device; and a searcher coupled to the system determination unit, the searcher is adapted to analyze a signal quality of at least one of the wireless communication systems identified to determine a probability of whether the wireless communications system will be acquired. 19. The integrated circuit according to claim 18, characterized in that the finder measures the resistance of a received signal corresponding to each identified wireless communications system. The integrated circuit according to claim 18, characterized in that the searcher calculates the signal to noise ratio Ec / I0 of a received signal for each identified wireless communications system. The integrated circuit according to claim 18, further characterized in that it comprises a memory coupled to the system determination unit, the memory stores a list of known communication systems, each known communication system has an associated geographic region and convenience relative. where the systems analyzed by the search engine are selected from the system table by the system determination unit. 22. The integrated circuit according to claim 18, characterized in that the system determining unit is adapted to transmit an instruction to the searcher, the instruction includes a test identi fi er; and wherein, in response to a received instruction, the browser analyzes the signal quality of at least one of the wireless communication systems identified using a test method identified by the test identifier. The integrated circuit according to claim 22, characterized in that the transmitted instruction further includes a threshold value, and wherein the searcher transmits a notification message to the system determination unit when at least one quality of the analyzed signal exceeds. the threshold value.