JP2006504291A - Method and apparatus for efficient selection and acquisition of a wireless communication system - Google Patents

Abstract

The mobile station includes a processing circuit and a memory. A group of wireless communication systems is selected according to a predetermined system acquisition procedure. The received signal corresponding to each selected system is analyzed to determine the likelihood that the selected system will be acquired by the mobile station. The selected group of systems is re-prioritized based on the results of the analysis to produce a more efficient system acquisition procedure. Next, the mobile station attempts to acquire the selected wireless communication system according to the system acquisition procedure.

Description

RELATED APPLICATION This application claims priority to US Provisional Patent Application No. 60 / 355,742, filed Feb. 5, 2002.
The present invention relates generally to wireless communications. More particularly, it relates to a method and apparatus for efficient selection and acquisition of a wireless communication system.

  Mobile devices often have connection means with more than one wireless communication system in the area. Mobile equipment for each system, depending on the equipment used by each system, the characteristics of the mobile equipment, the distance between the mobile equipment and the local base station, physical obstacles such as buildings and hills, and the amount of communication traffic on each system The available wireless service quality may vary. Wireless communication systems also include code division multiple access (CDMA), wideband CDMA (WCDMA), advanced mobile telephone service (AMPS), GSM, general packet radio service (GPRS) or high data signal rate (HDR) technology (eg, 1xEV technology). May support different multiple access wireless communication protocols. In addition, the charge charged to the user of the mobile device may vary depending on the time of day, the connection time with the wireless communication system, and whether the mobile device is listed as a subscriber to the wireless communication system.

  In order to help select the desired wireless communication system, conventional mobile devices store data describing known systems in a preferred roaming list (PRL). The PRL typically has a system table that stores a system identifier (SID) and a network identifier (NID) for each known wireless communication system, and an acquisition table that stores acquisition parameters including bandwidth, frequency, and mode for known wireless communication systems. Including. Within the system table, wireless communication systems are often grouped by region and sorted from the most desirable system to the least desirable system in each region. Also, the most desirable system in a particular region is usually a subscriber system, but may be a roaming system that provides mobile devices with a favorable combination of low cost and high service quality. A roaming system provides wireless services to unsubscribed mobile stations at a much higher rate than normal subscription services. Also, when a mobile device enters an area outside the area covered by the subscription service, when the subscription service is interrupted or otherwise cannot be obtained, or when the subscription service is only available at an unacceptably low quality level, A roaming system may be desirable.

  While the mobile device is starting up, an attempt is made to obtain the most desirable wireless communication system that can be used by the mobile device in the region where it is currently located and to register with that system. In one method, the mobile device identifies the region in which it is currently located, and then acquires and transfers the system from the most desirable system in the identified region to the least desirable system in the identified region. Each entry in the system table is tried one by one until the registration attempt is successful. The mobile device may also attempt to acquire and register a new wireless communication system during operation. For example, the mobile device may request acquisition of a new system, and the connection between the mobile device and the connected wireless communication system may be disconnected. Further, the wireless communication system that can be used by the mobile device may change depending on the position of the mobile device and changes in the surrounding environment. In order to provide mobile device users with the best combination of high quality and low price, many mobile devices regularly acquire and register a wireless communication system that is more desirable than the wireless communication system that the mobile device is using. Try. The mobile device searches the system table for a wireless communication system that is preferable to the current system used by the mobile device in the region, and if a more desirable system is found in the system table, the mobile device is in use. Disconnect the communication channel and try to acquire and register one more desirable system.

  System acquisition procedures, such as the system acquisition procedure described above, often attempt to acquire signals and register with the corresponding wireless communication system, followed by a single successful system acquisition and registration after subsequent failures. Would include. The preferred roaming list typically includes more than 50 systems, and under certain conditions, the mobile device may spend more than 60 seconds to examine each system in the preferred roaming list one by one before a successful acquisition attempt. Absent. These acquisition attempt failures are common and can be caused by various factors. For example, if the pilot signal is obstructed or weakened by a physical obstacle, or if the mobile device is outside the coverage area of the base station, the mobile device may not be able to detect the pilot signal transmitted from the system base station. unknown. Registration to the system may fail if the mobile device and system use incompatible protocol revisions and hardware, or otherwise the system will reject the mobile device registration attempt.

  Accordingly, there is a need in the art for methods and apparatus for efficient selection and acquisition of wireless communication systems.

  The present invention is a method and apparatus for efficient selection and acquisition of a wireless communication system. In the preferred embodiment, the mobile station selects a group of wireless communication systems according to a predetermined system acquisition procedure. The selected group of systems has a selection order, such as a selection order defined by the wireless service provider, which can be used by the mobile station during system acquisition and registration attempts. Next, the received signal corresponding to each selected system is analyzed to determine the likelihood that each corresponding system is acquired at the mobile station. Furthermore, the wireless communication system group is re-prioritized to create a more efficient system acquisition order based on the results of the analysis. The mobile station attempts to acquire and register one of the systems in the group of the re-assigned wireless communication system according to the acquisition order specified by the group.

Preferably, the mobile station includes a processing circuit, a memory, a communication transceiver, and an antenna. The processing circuit includes a control processor, signal processor, searcher, and system determination unit for controlling the operation of the mobile station. In the preferred embodiment, the mobile station is a multi-mode device and the processing circuitry is adapted to operate in either CDMA or AMPS mode. The memory preferably includes at least one lookup table, such as a system table, an acquisition table, and a candidate list, and includes volatile and non-volatile random access memory that stores a preferred roaming list. The system determination unit is adapted to select at least one wireless communication system from the system table according to a system acquisition procedure. In a preferred embodiment, the system determination unit stores the plurality of systems selected in the candidate list and instructs the searcher to analyze the received signal corresponding to each system in the candidate list. For each listed system, the searcher instructs the transceiver to switch to the corresponding channel of the system and the received signal is analyzed. The analysis of the received signal should be less than the time required to measure the received signal strength (Rx) of each system, measure the signal-to-noise ratio E _C / I ₀ , or test the complete system acquisition and registration. May include other tests. Other tests are tests that help determine whether a candidate system is likely to be acquired.

  After each system is analyzed, the selected group of systems is re-prioritized based on the results of the analysis. In the preferred embodiment, all of the systems are reordered so that the system with the highest acquisition likelihood is selected first. In a first alternative embodiment, the order of desirability is preserved, and at each level of desirability, the system selected using the analysis results is reordered. In a second alternative embodiment, desirability information for each selected system is adjusted based on the analysis results, and then the selected group of systems is reordered using this adjusted desirability information. It is done. In a third alternative embodiment, systems whose analysis results corresponding to each system are lower than the threshold are excluded from the selected group of systems.

  Next, the mobile station tries to acquire and register the wireless communication system. First, the system with the highest priority is selected from the re-prioritized candidate list, and an attempt is made to acquire and register the selected system. Any system acquisition method may be used, including conventional system acquisition methods well known in the art. If the acquisition / registration attempt is not successful, the wireless communication system having the next highest priority is selected from the candidate list and the next acquisition / registration is attempted. This process continues until the system acquisition / registration attempt succeeds or there are no additional candidate systems. In the preferred embodiment, if the acquisition / registration attempt is successful, the wireless communication system is used for subsequent wireless communication services. In an alternative embodiment, the acquired wireless communication system has a known region and attempts to acquire and register a more preferred wireless communication system within that region.

  In the first alternative system acquisition procedure, the first system is selected according to the system acquisition procedure. Any system acquisition procedure may be used including selecting the system most recently used by the mobile station. The signal quality of the selected system is measured and if the system is not expected to be acquired, the next system is selected according to the system acquisition procedure. If the selected system is expected to be acquired, attempt to acquire and register the selected system. If the acquisition / registration attempt is successful, the wireless communication system is used for subsequent wireless communication services. Otherwise, the next system is selected according to the system acquisition procedure.

  Those of ordinary skill in the art will have a more complete understanding of the method and apparatus for efficient selection and acquisition of wireless communication systems and the realization of additional effects and objectives therefrom by considering the following detailed description of the preferred embodiments. And would be able to get Reference will be made to the appended drawings, which will first be described briefly. The features, objects, and advantages of the present invention will become more apparent from the detailed description set forth below when taken in conjunction with the drawings in which like reference characters generally refer to the same.

  A preferred embodiment of the present invention will be described with reference to FIG. The mobile station 2 operates in an area 4 served by at least one base station 6. Each base station 6 is connected to a network 8. This network is part of a larger wireless communication system that supports at least one multiple access wireless communication protocol. This wireless communication system may be, for example, code division multiple access (CDMA), wideband CDMA (WCDMA), advanced mobile telephone service (AMPS), GSM, general packet radio service (GPRS) or high data rate (HDR) technology (eg, 1xEV technology). ). The mobile station 2 is adapted to communicate with at least one base station 6 whether stationary or moving, such as a mobile phone, a pager, a personal digital assistant (PDA), a vehicle navigation system or a portable computer. Any arbitrary wireless device may be used. In the preferred embodiment, the mobile station is a multi-mode device adapted to operate in both CDMA and AMPS modes.

  Mobile station 2 includes a list of known wireless communication systems such as preferred roaming list (PRL) 10. The PRL 10 is stored in the non-volatile memory of the mobile station 2 and includes a list of radio communication systems and corresponding acquisition parameters, which are used by the mobile station 2 while attempting acquisition and registration of the radio communication system. Is. In the preferred embodiment, the wireless communication systems listed in PRL 10 are grouped by region and sorted from the most desirable system to the least desirable system in each region. As is known in the art, the PRL 10 is maintained by the mobile station's wireless service provider and through the wireless service provider or other wireless service provider that has agreed to provide roaming service to the mobile station 2. 2 may include a list of wireless communication systems that can be used.

  During operation, the mobile station 2 attempts to acquire and register an available wireless communication system that provides wireless services to the mobile station 2. Initially, 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 that may be used by the mobile station 2 during system acquisition and registration attempts. For example, in the preferred embodiment, a plurality of wireless communication systems within the mobile station region 4 are selected and sorted from the most desirable system to the least desirable system in each region. Next, the received signal corresponding to each selected system is analyzed to determine the relative likelihood that each corresponding system is acquired by the mobile station 2. Furthermore, groups of wireless communication systems are re-prioritized to create a more efficient system acquisition order based on the results of the analysis. The mobile station 2 selects a system having the highest relative priority from the re-prioritized group, and tries to acquire and register the selected system. If the acquisition / registration attempt is successful, the selected system is used by the mobile station 2 for wireless communication. Otherwise, it tries to acquire / register the system from the group with the next highest priority.

  A preferred embodiment of the mobile station 2 will be described with reference to FIG. The mobile station 2 includes a processing circuit 80, a memory 24, a communication transceiver 84 and an antenna 86. Preferably, the processing circuit 80 includes a control processor 90, a signal processor 92, a searcher 94 and a system determination unit 96 for controlling the operation of the mobile station 2. Preferably, memory 24 includes system table 100 and acquisition table 102 and includes volatile and non-volatile random access memory that stores preferred roaming lists. Memory 24 may include at least one lookup table, such as a list of the most recently used systems 106, and program instructions for execution by processing circuitry 80.

  Searcher 94 is adapted to identify valid signals, such as pilot signals, synchronization channels and paging channels received by transceiver 84 through antenna 86. The design and implementation of searcher hardware for CDMA acquisition is described in US Pat. No. 5,109,390 “Diversity Receiver for CDMA Cellular Phone System”. This invention is assigned to the assignee of the present invention and incorporated herein by reference. Searcher 94 is further adapted to perform a preliminary acquisition analysis of at least one candidate communication system.

  The system determination unit 96 is adapted to select at least one wireless communication system 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 transfer the acquired parameters to the searcher 94. This searcher attempts to acquire one of the selected systems. In an alternative embodiment, the system determination unit 96 determines whether the wireless communication system in use is the most desirable system in the area, and the more desirable system is available by the mobile station 2 when a more desirable system is available. Start an acquisition attempt. A method and apparatus for performing preferred system selection in a mobile station operable in multiple regions is disclosed in US Pat. No. 6,085,085, “Method and apparatus for preferred system selection”. This invention is assigned to the assignee and incorporated herein by reference.

It should be understood that the mobile station 2 shown in FIG. 2 is merely exemplary, 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 may be implemented in various hardware configurations using normal circuit elements such as at least one processor, memory, and ASIC. In addition, voice communications, high-speed data communications, video communications, Internet applications such as e-mail and WWW connections, positioning (eg, gpsOne ^™ developed by the assignee), personal navigation, voice recognition, integrated removable storage devices, and local The mobile station 2 may be adapted for short-range wireless connections with peripheral devices and devices. In the preferred embodiment, processing circuit 80 includes a mobile station modem chipset that integrates GPS-based positioning and digital and analog functions. This chipset was developed by the assignee.

  A preferred embodiment of the system table 100 will be described with reference to FIGS. 2 and 3a. The system table 100 includes a list of wireless communication systems that the mobile station 2 uses during acquisition and registration attempts of the wireless communication system. As illustrated, each record in the system table 100 includes a system identifier (SID) 100a, a network identifier (NID) 100b, an indication of whether the system is favorable or negative (P / N) 100c, and the region covered by the system. An identifier (region) 100d, desirability information 100e, and a pointer (AT pointer) 100f to a record in the acquisition table 102 are preferably included. Is each wireless communication system listed in the system table 100 identified by a unique set of SIDs 100a, NID 100b and designated by the P / N 100c as a preferred system that may be used by the mobile station 2 during roaming? Or as a negative system that should not be used by the mobile station 2 during roaming. In an alternative embodiment, the wireless communication system listed in the system table 100 may include other system identifiers, such as unique bandwidth, mode and frequency, and Internet Protocol 6th Edition (IPv6) address or public land mobile network ( PLMN) identifier may be used. The wireless communication systems are preferably grouped by region 100d and stored in the system table 100 in order from the most desirable system to the least desirable system in each region using desirability information 100e.

  A preferred embodiment of the acquisition table 102 will be described with reference to FIG. The acquisition table 102 includes a list of parameters necessary for acquisition of the wireless communication system listed in the system table 100. As shown, each record in the acquisition table 102 preferably includes a mode 102a, a band 102b, and a frequency 102c. System table 100 and acquisition table 102 are preferably stored in non-volatile memory and periodically downloaded by an external information source, such as a mobile station wireless service provider, through a wireless connection or by other data transfer methods. Updated. It will be appreciated that alternative configurations for the PRL, system table 100 and acquisition table 102, and alternative identification and acquisition parameters may be used in accordance with the present invention.

  As shown in FIG. 4, the memory includes at least one lookup table 104. In the preferred embodiment, the lookup table contains a list of the most recently used (MRU) system table 104a that stores a list of the most recently used systems by mobile station 2, a list of systems that have been selected as acquisition candidates. A candidate list 104b including the priority table 104c that holds the local priority setting for the mobile station 2 is included. Information including history information that tracks usage of other systems may also be stored in the lookup table. The look-up table is preferably stored in the volatile portion of the memory 24, although in alternative embodiments at least one look-up table may be stored in the non-volatile portion of the memory 24.

  A preferred system acquisition procedure for the mobile station 2 will be described with reference to the flowcharts of FIGS. The system acquisition procedure is preferably performed by the system determination unit 96. In step 200, a group of wireless communication systems is selected from a list of stored systems according to a predetermined system acquisition procedure. In the preferred embodiment, a plurality of wireless communication systems in region 4 of the mobile station are selected from system table 100 and the corresponding system identifiers are stored in candidate list 104b in memory 24. In an alternative embodiment, candidate list 104b may include other data such as acquisition parameters and desirability information corresponding to selected systems. Candidate list 104b is preferably rearranged in an initial order of priorities (eg, from the most desirable system to the least desirable system) as defined by a predetermined system acquisition procedure. Although system selection using PRL has been shown, it will be understood that other system acquisition procedures may be used in accordance with the preferred embodiment of the present invention. For example, in an alternative embodiment, the system acquisition procedure may include selecting a system group from the MRU 104a or other stored system list.

  As is known in the art, the system table 100 identifies the preferred system acquisition order used by the mobile station 2 during a system acquisition / registration attempt. However, this system acquisition order is not necessarily the most efficient system selection order for acquiring and registering a wireless communication system. The selection order identified by the system table 100 is usually determined by the mobile station's wireless service provider based on factors not related to the likelihood that each listed system is acquired by the mobile station 2. For example, the desirability of each system is the cost of using the system, the quality of communication service provided by the system, the protocol used by the system, support for unique features, and the mobile station 2 is a subscriber to the wireless communication system. May be determined using criteria such as whether it is listed as.

  In order to increase the efficiency of the system acquisition / registration process, the mobile station 2 analyzes the received signal corresponding to each system in the candidate list 104b (step 202), and adjusts the system acquisition order based on the result of the analysis (step 202). Step 204). In a first preferred embodiment, the analysis of the received signal includes a measurement of the received signal strength (Rx) of each system. In operation, the searcher 94 searches the identified systems one by one in the candidate list 104b stored in the memory 24. In an alternative embodiment, the candidate list may be transmitted from the system determination unit 96 to the searcher 94. For each system listed, the searcher 94 instructs the transceiver 84 to switch to the corresponding channel of the system. The received signal strength is then measured and stored in the candidate list 104b. If the received signal strength measurement is relatively low, the probability that the candidate system is available for acquisition will be low. If the received signal strength measurement is relatively high, the probability that a candidate system will be obtained will be high. It will be appreciated that signal strength measurements for a system group can usually be completed in a time sufficiently shorter than acquisition and registration attempts of each system in the group. In alternative embodiments, other tests may be performed on the received signal to help determine whether a candidate system is likely to be acquired.

In a first alternative embodiment, analyzing the received signal includes determining whether the received signal is likely a CDMA signal. In this embodiment, system determination unit 96 commands searcher 94 to measure the signal to noise ratio E _C / I ₀ . Here, E _C is the received signal strength, and I ₀ is the total received thermal noise on the channel. In a CDMA system, this measurement gives an indication of the portion of the received signal that is available. If E _C / I ₀ is relatively large, there is a high probability that the system will be acquired. E _C / I ₀ gives a more reliable indication of whether the signal is likely to be acquired than the raw measured signal strength.

  In a second alternative embodiment, the system determination unit 96 and searcher 94 support multiple test modes and acquisition methods, and may be adapted to use at least one analysis method alone or in combination. The test mode may be determined by user selection, mobile station configuration, the current operating state of the mobile station or other criteria. The searcher 94 preferably operates according to instructions received from the system determination unit 96, which is adapted to send candidate system test instructions and system acquisition instructions. The candidate system test instructions include parameters for identifying the candidate list, an identifier for the test to be performed for each system, and a minimum threshold that each candidate system should satisfy. The searcher 94 executes the received command and returns a plurality of candidate systems that meet the test requirements. In the preferred embodiment, searcher 94 modifies the candidate list stored in memory. The system determination unit 96 is further adapted to analyze the test results and send a search system 94 with system acquisition instructions including parameters identifying a candidate list.

  In step 204, the selected group of systems is re-prioritized based on the analysis to form a more efficient system acquisition order. In the preferred embodiment, all systems are reordered so that the system with the highest likelihood of acquisition is selected first. In a first alternative embodiment, multiple selected systems have the same level of desirability. At each level of desirability, the selected system is reordered using the measured signal strength from the most probable system to the least probable system. In a second alternative embodiment, desirability information for each selected system is adjusted based on test measurements. For example, the relative desirability of a system whose signal strength measurement is greater than a first threshold may be adjusted upward. On the other hand, the relative desirability of a system whose signal strength measurement is less than the second threshold may be adjusted downward. The selected group of systems is then rearranged using the adjusted desirability information. In a third alternative embodiment, systems with test signal quality below the threshold are excluded from the selected group of systems. For example, candidate systems that correspond to measurement signal strengths lower than -90 dB may be excluded from the candidate list. Other criteria may also be used to eliminate and reorder candidate systems. For example, a weighting factor may be used that takes into account measured signal strength, whether the system has been used recently, desirability ranking, and other information.

  After the group of selected systems has been re-prioritized, the mobile station 2 tries to acquire and register one of the wireless communication systems in the group. In step 206, the system with the highest level of priority is selected from the candidate list 104b. In the preferred embodiment, the system has a relatively high desirability level and high likelihood that acquisition / registration attempts based on measured signal quality, such as signal strength measurements, will be successful. Step 208 attempts to acquire and register the selected system. Any system acquisition method may be used, including normal system acquisition methods well known in the art. In the preferred embodiment, mobile station 2 is adapted to acquire a CDMA system. To obtain a CDMA system, the searcher 94 instructs the transceiver 84 to switch to the communication channel of the selected CDMA system and attempts to receive a pilot signal. Searcher 94 attempts to match the received pilot signal by testing various pseudo-random noise (PN) offsets in the received signal until a match is obtained. Once the pilot signal is acquired, the processing circuit 80 receives information for the CDMA forward channel and a phase reference for signal demodulation. Next, the processing circuit 80 attempts to acquire a synchronization channel associated with the identified pilot channel. This synchronization channel transmits basic system information such as the transmitting wireless communication system and the unique SID / NID of the network, and synchronization information. The processing circuit 80 adjusts the timing according to the received information, and then switches to the paging channel of the base station. When the mobile station 2 is not assigned to a traffic channel, the paging channel is used by the local base station of the current communication system that communicates with the mobile station 2. Through the paging channel, the base station notifies the mobile station 2 of input messages, such as incoming telephone calls or notification of incoming voice mail messages.

  If the acquisition / registration attempt is successful (step 210), the selected system is used by the mobile station 2 for wireless communication. If the acquisition / registration attempt is unsuccessful, the next priority wireless communication system is selected from the candidate list at step 212 and control returns to step 208 for the next acquisition / registration attempt. If the searcher 94 cannot acquire the selected system (step 210), the searcher 94 acquires each remaining system according to the selection order until a wireless communication system is acquired or there are no candidate systems. Would try. In an alternative embodiment, if the acquisition / registration attempt is successful at step 210, the process returns to step 200 for group selection of systems that are preferred over the selected systems in the current region.

  An alternative system acquisition procedure is shown in the flowchart of FIG. In step 250, a first system is selected according to a system acquisition procedure. Any system acquisition procedure may be used including selecting the system most recently used by the mobile station 2. The signal quality of the selected system is measured at step 252. If the system is likely to be acquired (step 254), an attempt is made to acquire and register the system selected in step 256. In the preferred embodiment, the system is likely to be acquired if the measured signal quality exceeds a predetermined threshold. If no system is expected to be acquired, the next system is selected in step 260 according to the system acquisition procedure. If the acquisition / registration attempt is successful (step 258), the mobile station 2 uses the system selected for the subsequent wireless communication service. If the acquisition / registration attempt is unsuccessful, the next wireless communication system is selected at step 260 and control returns to step 252.

  As described above, having described a preferred embodiment of a method and apparatus for efficient selection and acquisition of a wireless communication system, the certain advantages of the system described herein have been achieved. It will be obvious to those skilled in the art. In addition, it should be understood that various changes, adaptations, and alternative embodiments may be made within the scope and spirit of the invention.

Preferred embodiment of the invention. A mobile station according to a preferred embodiment of the present invention. Fig. 4 is a system table according to a preferred embodiment of the present invention. The acquisition table according to a preferred embodiment of the present invention. A preferred lookup table used by a mobile station according to a preferred embodiment of the present invention. The flowchart which shows a preferable system selection and acquisition procedure. The flowchart which shows an alternative system selection and acquisition procedure.

Claims (23)

In a mobile station storing a list of wireless communication systems, the system acquisition procedure is:
Selecting a group of radio communication systems from the list according to a predetermined system acquisition procedure, wherein the groups of the radio communication system have a first system acquisition order;
Measuring signal quality for each selected system;
Re-prioritizing groups of wireless communication systems according to measured signal quality, wherein the re-prioritized groups of wireless communication systems have a second system acquisition order;
Attempting to acquire a wireless communication system having the highest priority according to the second system acquisition order. The list of wireless communication systems is a preferred roaming list that includes region identifiers, and selecting a group of wireless communication systems includes determining a current region of the mobile station and determining a region identifier corresponding to the current region of the mobile station. Selecting a listed wireless communication system having
The method of claim 1, wherein the first system acquisition order is based on a relative order of wireless communication systems selected in a preferred roaming list. Each wireless communication system identified in the preferred roaming list has a corresponding desirability level and at least two selected systems sharing the same level of desirability.
The method of claim 2, wherein re-prioritizing includes searching for selected systems that share the same desirability level and reordering of systems searched by measured signal strength. Each wireless communication system identified in the preferred roaming list has a corresponding desirability level, and re-prioritizing comprises:
For each selected system, adjusting a corresponding desirability level based on the measured signal strength, the adjusted desirability criteria being stored in a group of wireless communication systems;
Reordering groups of wireless communication systems according to adjusted desirability levels.   The method of claim 1, wherein the re-prioritizing step includes excluding the selected system from the group if the corresponding measured signal quality of the selected system fails to meet a minimum threshold. The method of claim 1, wherein measuring the signal quality includes calculating an E _C / I ₀ ratio of the received signal. A preferred roaming list comprising a first plurality of system identifiers and corresponding acquisition parameters;
A processing circuit adapted to select a plurality of wireless communication systems from a preferred roaming list according to a predetermined system acquisition procedure, wherein the selected wireless system has a corresponding system acquisition order;
The processing circuit is further adapted to measure the signal quality of each selected system and to change the system acquisition order based on the measured signal quality, the changed system acquisition order being a system A mobile station including a processing circuit that increases the efficiency of the acquisition process. The selected wireless communication system includes a corresponding desirability criterion,
The processing circuit is further adapted to adjust the corresponding desirability criterion of the selected system if the corresponding signal strength measurement exceeds the first threshold and is selected using the adjusted desirability criterion. 8. A mobile station according to claim 7, adapted to reorder different wireless communication systems.   8. The mobile station according to claim 7, wherein the measured signal quality for each system includes a signal-to-noise ratio of the received signal, wherein the signal-to-noise ratio corresponds to a likelihood that a corresponding system is obtained. A method for obtaining a wireless communication system in a multi-mode mobile station adapted to operate in CDMA and AMPS modes comprises:
Analyzing a signal received on a channel associated with a candidate communication system;
Determining whether the candidate communication system is likely to be obtainable by a mobile station based on the analysis of the received signal;
Attempting to obtain a candidate communication system only if the candidate communication system is likely to be obtainable.   11. The method of claim 10, wherein the analyzing step includes switching to a channel associated with a candidate communication system and testing the signal quality of the received signal.   The mobile station includes a table of known communication systems, each known communication system has a relative desirability, and candidate communication systems are selected according to a predetermined system acquisition procedure from the table of known communication systems. The method of claim 11.   The method of claim 11, wherein the tested signal quality is a received signal strength measurement.   The method of claim 11, wherein the tested signal quality is a signal to noise ratio of the received signal.   The method of claim 11, wherein the candidate communication system is likely to be available if the measured signal quality exceeds a predetermined threshold.   12. The method of claim 11, further comprising selecting a set of candidate communication systems, wherein the analyzing and determining steps are repeated in the set for each candidate communication system, and the trial step is most acquired. A method performed for a candidate communication system that is likely to   The method of claim 16, further comprising rearranging candidate communication systems in order of measurement signal quality, wherein the rearrangement order defines an acquisition order for the set of candidate communication systems. In wireless equipment,
A system determination unit adapted to identify a plurality of candidate communication systems within the current region of the wireless device;
A searcher coupled with a system determination unit, the searcher adapted to analyze the signal quality of at least one identified wireless communication system to determine the likelihood that the wireless communication system is acquired; Integrated circuit including   The integrated circuit of claim 18, wherein the searcher measures received signal strength corresponding to each identified wireless communication system. 19. The integrated circuit of claim 18, wherein the searcher calculates a signal to noise ratio E _C / I ₀ of the received signal for each identified wireless communication system. The integrated circuit further includes a memory coupled to the system determination unit, the memory storing a list of known communication systems, each known communication system having an associated region and relative desirability;
19. The integrated circuit of claim 18, wherein the plurality of systems analyzed by the searcher are selected from a system table by a system determination unit. The system determination unit is adapted to transmit instructions to the searcher, the instructions including a test identifier;
19. The integrated circuit according to claim 18, wherein in response to the receiving command, the searcher analyzes the signal quality of the at least one specified wireless communication system using a test method specified by the test identifier.   23. The integrated circuit of claim 22, wherein the communicated instructions further include a threshold, and the searcher sends a notification message to the system determination unit when at least one analyzed signal quality exceeds the threshold.

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