KR20040077931A - Method and apparatus for efficient selection and acquisition of a wireless communications system - Google Patents

Abstract

The present invention relates to a mobile station comprising a processing circuit and a memory. The group of wireless communication systems is selected according to a predetermined system acquisition process. The received signal corresponding to each selected system is analyzed to determine the likelihood that the selected system is likely to be obtained 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 attempts to acquire the selected wireless communication system according to the system acquisition sequence.

Description

METHOD AND APPARATUS FOR EFFICIENT SELECTION AND ACQUISITION OF A WIRELESS COMMUNICATIONS SYSTEM}

The mobile device has access to one or more wireless communication systems in its geographic area. The quality of wireless service available on a mobile device depends 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 obstacles such as buildings and hills, and the volume of communication traffic on each system. It depends on the system. Wireless communication systems may include code division multiple access (CDMA), wideband CDMA (WCDMA), enhanced mobile phone service (AMPS), mobile communications globalization system (GSM), universal packet radio service (GPRS) or high data rate (HDR) technology ( For example, 1xEV technology). In addition, the cost charged to a user of a mobile device depends on the time of day, the duration of the connection with the wireless communication system and whether the mobile device is listed as a subscriber of the wireless communication system.

To assist in the selection of the desired wireless communication system, typical mobile devices store data describing known systems in the preferred roaming list (PRL). The PRL is typically 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 band, frequency and mode for a known wireless communication system. It includes. Within the system tables, wireless communication systems are often grouped by geographic area and stored from the most desirable system to the least desirable system in each area. The most preferred system in a particular geographic area is typically a subscriber system, but may also be a roaming system capable of providing low cost, high quality services to mobile devices. Roaming systems generally provide wireless services to non-subscriber mobile devices at a much higher cost than the service to the subscriber, and the mobile device enters a geographic area that is located outside the coverage area of the service to the subscriber of the mobile device. It is desirable when services for a subscriber are blocked or otherwise unavailable or when services for a subscriber are available with an unacceptable low level of quality.

During the power-up sequence of the mobile device, the mobile device attempts to obtain and register the most desirable wireless communication system available within its current geographic area. In one approach, the mobile device identifies its current geographic area and then obtains the system from the most preferred system in the identified geographic area through entries in the system table to the least desirable system in the identified geographic area. And proceed until the registration attempt is successful. The mobile device attempts to acquire and register a new wireless communication system during operation. For example, when the connection between the mobile device and the current wireless communication system is lost, acquisition of a new system is required by the mobile device. In addition, the wireless communication system available in a mobile device may change as the location of the mobile device and its surrounding environment change. In order to provide the best combination of high quality, low cost to users of mobile devices, many mobile devices periodically attempt to obtain and register a wireless communication system that is more desirable than current wireless communication systems used by mobile devices. The mobile device searches the system table for wireless communication systems in its geographic area that is more desirable than the current system used by the mobile device, and if more preferred systems are found in the system table, the mobile device can We will attempt to obtain and register one of the more desirable systems off the channel.

System acquisition sequences, such as the system acquisition sequences described above, will often result in one successful system acquisition and registration after a series of failed attempts to acquire a signal and register with the wireless communication system. The preferred roaming list typically includes more than 50 systems, and under certain conditions the mobile device consumes at least 60 seconds while stepping through the systems in the desired roaming list before the acquisition attempt is successful. These failed acquisition attempts are common and depend on many factors. For example, the mobile device will not be able to detect the pilot signal transmitted from the system base station if the pilot signal is blocked or weakened by physical obstacles or when the mobile device is located outside the coverage area of the base station. Registration of the system may or may not reject the mobile device's attempt to register if the mobile device and the system use incompatible protocol modifications and hardware.

As mentioned above, there is a need for a method and apparatus for efficiently selecting and obtaining a wireless communication system.

The present invention prioritizes US Patent Application No. 60 / 355,742, filed February 5, 2202.

The present invention relates generally to methods and apparatus for efficiently selecting and obtaining wireless communications, in particular wireless communications systems.

1 illustrates a preferred embodiment of the present invention.

2 is a mobile station according to a preferred embodiment of the present invention.

3A is a system table according to a preferred embodiment of the present invention.

3B is an acquisition table according to a preferred embodiment of the present invention.

4 illustrates preferred lookup tables used in accordance with a preferred embodiment of the present invention.

5 is a flowchart illustrating a preferred system selection and acquisition process.

6 is a flow diagram illustrating an optional system selection and acquisition process.

The present invention relates to a method and apparatus for efficiently selecting and obtaining a wireless communication system. In a preferred embodiment, the mobile station selects a group of wireless communication systems according to a predetermined system acquisition process. The selected groups of systems have an order of priority equal to the order of preference determined by the wireless service provider, which is used by the mobile station during system acquisition and registration attempts. Next, received signals corresponding to each selected system are analyzed to determine whether each corresponding system has been obtained by the mobile station, and so forth. The group of wireless communication systems is then reprioritized based on the results of the analysis to create a more efficient system acquisition order. The mobile station attempts to acquire and register one of the in-group systems to which the wireless communication system has been reprioritized according to the acquisition order specified by the group.

The mobile station preferably comprises processing circuitry, memory, communication transceiver and antenna. The processing circuit includes a control processor, a signal processor, a searcher and a system determination unit for controlling the operation of the mobile station. In a preferred embodiment, the mobile station is a multi-mobile device and the processing circuit is adapted to operate in either CDMA or AMPS mode. The memory preferably includes volatile and nonvolatile random access memories that store a preferred roaming list comprising a system table and one or more lookup tables such as an acquisition table and a candidate list. The system determination unit is adapted to select one or more wireless communication systems from the system table according to the system acquisition process. In a preferred embodiment, the system determination unit stores the selected systems in the candidate list and instructs the searcher to analyze the received signal corresponding to each of the systems 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. Analysis of the received signals requires less time than measuring the received signal strength (Rx) of each system, measuring the signal-to-noise ratio E _c / I _O , or attempting to acquire and register the system in which the test is completed. If so, other tests are included to assist in determining whether the system will be acquired.

After each system is analyzed, the group of selected systems is reprioritized based on the results of the analysis. In a preferred embodiment, all systems are stored such that the systems most likely to be acquired are selected first. In a first alternative embodiment, the order of preference is maintained and at each level of preference, the selected systems are stored using the analysis results. In a second alternative embodiment, the preference information for each selected system is adjusted based on the analysis results and the group of selected systems is stored using the adjusted preference information. In a third alternative embodiment, each system with a corresponding analysis result having a value below the threshold is removed from the group of selected systems.

The mobile station then attempts to acquire and register a wireless communication system. The system with the highest level of priority is selected first from the prioritized candidates and attempts to acquire and register for the selected system. Any system acquisition method is used, including known conventional system acquisition methods. If the acquisition / registration attempt is not successful, then the wireless communication system with the next highest priority is selected from the candidate list and another acquisition / registration is attempted. This process continues until the system acquisition / registration attempt is successful or until no additional candidate system exists. In a preferred embodiment, if the acquisition / registration attempt is successful, the wireless communication system is used for future wireless communication services. In an alternative embodiment, the obtained wireless communication system has a known geographic area and attempts to obtain and register a more desirable wireless communication system in the geographic area.

In a first optional system acquisition sequence, the first system is selected according to the system acquisition process. Any system procedure is used, including selecting the system that was most recently used by the mobile station. The signal quality of the selected system is measured and if it is unlikely to be acquired, the next system is selected according to the system acquisition process. If the selected system is likely to be acquired, an attempt is made to acquire and register the selected system. If the acquisition / registration attempt is successful, the wireless communication system is used for future wireless communication services. Otherwise, the next system is selected according to the system acquisition process.

A more complete understanding of the method and apparatus for efficient selection and acquisition of wireless communication systems is provided to those skilled in the art through the following detailed description of the preferred embodiment along with the realization of further advantages and objects of the present invention. References to the accompanying drawings are described first briefly.

The features, objects, and advantages of the present invention will become apparent from the following detailed description taken in conjunction with the accompanying drawings, in which like reference characters refer to like features.

A preferred embodiment of the present invention will be described with reference to FIG. The mobile station 2 operates in a geographic area 4 serviced by at least one base station 6. Each base station 6 is connected to a network 8, which is code division multiple access (CDMA), wideband CDMA (WCDMA), enhanced mobile phone service (AMPS), mobile communications globalization system (GSM), universal packet radio service Part of many wireless communication systems that support at least one multiple access wireless communication protocols, such as (GPRS) or high data rate (HDR) technology (eg, 1xEV technology). The mobile station 2 is any fixed or mobile device that is adapted to wirelessly communicate with at least one base station 6, such as a cellular telephone, a pager, a personal digital assistant (PDA), a car navigation system or a portable computer. In a preferred embodiment, the mobile station is a multi-mode device adapted to operate in both CDMA and AMPS modes.

The mobile station 2 comprises a list of known wireless communication systems, such as a preferred roaming list (PRL) 10. The PRL 10 is stored in the nonvolatile memory of the mobile station 2 and includes a list of corresponding acquisition parameters used by the mobile station 2 during attempts to acquire and register the wireless communication system and the wireless communication system. In a preferred embodiment, the wireless communication systems listed in the PRL 10 are grouped by geographic area and stored from the most desirable system in each area to the least desirable system. As is known, the PRL 10 is maintained by the wireless service provider of the mobile station and used at the mobile station 2 through its wireless service provider or other wireless service providers agreed to provide roaming services to the mobile station 2. It contains a list of possible wireless communication systems.

In operation, the mobile station 2 attempts to acquire and register an available wireless communication system that provides wireless services to the mobile station 2. First of all, a group of wireless communication systems is selected from the PRL in accordance with the desired system acquisition process. The system groups have an order of priority used by the mobile station 2 during system acquisition and registration attempts. For example, in a preferred embodiment, wireless communication systems in the geographic area 4 of the mobile station are selected and stored as the least desirable system from the most preferred system in each area. The received signal corresponding to each of the selected systems is then analyzed to determine the relative likelihood that each of those systems is likely to be obtained by the mobile station 2. Groups of wireless communication systems are reprioritized based on the results of the analysis to create more efficient system acquisition orders. The mobile station 2 selects a system from the group of re-priorities having the highest relative priority, and attempts 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. If not, it attempts to acquire / register the system from the group with the next highest priority.

2, a preferred embodiment of the mobile station 2 is described. The mobile station 2 includes a processing circuit 80, a memory 24, a communication transceiver 84, and an antenna 86. The processing circuit 80 preferably comprises a control processor, a signal processor 92, a searcher 94 and a system determination unit 96 for controlling the operation of the mobile station 2. The memory 24 preferably includes both volatile and nonvolatile random access memories that store a preferred roaming list that includes the system table 100 and the acquisition table 102. The memory 24 includes one or more lookup tables 104, such as a list most recently used by the system, and program instructions executed by the processing circuit 80.

The searcher 94 is adapted to identify valid channels, such as pilot signals, synchronization channels, and paging channels, received by the transceiver 84 via the antenna 86. The design and implementation of searcher hardware for CDMA acquisition is disclosed in US Pat. No. 5,109,390, entitled "Diversity Receiver in CDMA Cellular Telephone System," which is assigned to the assignee of the present invention and is incorporated by reference. The searcher 94 is further adapted to perform a preliminary acquisition analysis of one or more candidate systems.

The system determination unit 96 selects one or more wireless communication systems from the system table 100 and retrieves corresponding acquisition parameters from the acquisition table 102. System determination unit 96 is adapted to send acquisition parameters to searcher 94, which attempts to acquire one of the selected systems. In an alternative embodiment, the system determination unit 96 determines whether the current wireless communication system is the most preferred system in the current geographic area of the mobile device, and more preferred system by the mobile station 2 when more preferred systems are available. Start attempting to acquire it. A method and apparatus for performing preferred system selection in a mobile station that can operate within a number of geographic areas is disclosed in US Pat. No. 6,085,085 entitled “Method and Apparatus for Performing Preferred System Selection.” It is assigned and is incorporated by reference.

It will be appreciated that the mobile station 2 shown in FIG. 2 is merely illustrative and that alternative configurations and optional features may be considered within the spirit and scope of the present invention. For example, the components of the mobile station 2 are implemented in various hardware configurations using conventional circuit elements such as one or more processors, memories and application specific integrated circuits (ASICs). The mobile station 2 can be used for voice communications, high-speed data communications, video communications, Internet applications such as email and world wide web access, location positioning (e.g. gpsOne ^TM developed by the assignee), personal navigation, voice recognition, integration It is adapted for short-range wireless connection with removable storage devices and local peripherals and devices. In a preferred embodiment, the processing circuit 80 includes a Mobile Station Modern chipset developed by the assignee, which integrates digital and analog functions with GPS-based positioning positioning.

2 and 3A, a preferred embodiment of the system table 100 is described below. System table 100 includes a list of wireless communication systems used by mobile station 2 while attempting to acquire and register a wireless communication system. As shown, each record in the system table 100 is an indicator of a system identifier (SID) 100a, a network identifier (NID) 100b, and whether the system is preferred or negative (P / N). 100c, an indicator for geographic area 100d covered by the system, preference information 100e, and a pointer (AT pointer) 100f to a record in acquisition table 102. Each wireless communication system listed in the system table 100 is identified via a unique SID 100a, NID 100b pair, and identifies the preferred system or P / N 100c used by the mobile station 2 during roaming. It is designated 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 is identified using a unique band, mode and frequency, and other system identifiers such as an Internet Protocol Version (IPV6) address or a Public Land Mobile Network (PLMN) identifier. do. Wireless communication systems are preferably grouped by geographic region 100d and stored in system table 100 in the stored order of least preferred system from least preferred system in each region using affinity information 100e. do.

Referring to FIG. 3B, a preferred embodiment of the acquisition table 102 is described below. The acquisition table 102 includes a parameter list required for acquisition of the wireless communication system listed in the system table 100. As shown, each record in acquisition table 102 preferably includes mode 102a, band 102b and frequency 102c. System table 100 and acquisition table 102 are preferably stored in non-volatile memory and periodically updated by an external source, such as a wireless service provider of a mobile station, via a download connection or other data transfer method of a wireless connection. . It will be appreciated that optional configurations and optional identification and acquisition parameters for the PRL, the systems table 100 and the acquisition table 102 are used in accordance with the present invention.

As shown in FIG. 4, the memory also includes one or more lookup tables 104. In a preferred embodiment, the lookup table includes a most recently used (MRU) system table 104a that stores a list of systems most recently used by the mobile station 2 and a list of systems that were selected as candidates for acquisition. And a preference table 104c that maintains local preference settings for the list 104b and the mobile station 2. Other information is also stored in a lookup table that includes historical information that tracks the use of each system. Lookup tables are preferably stored in a volatile portion of memory 24, although in alternative embodiments one or more lookup tables may be stored in a nonvolatile portion of memory 24.

The preferred system acquisition sequence for the mobile station 2 will be described below with reference to the flowcharts of FIGS. 2 and 5. The system acquisition sequence 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 in accordance with a predetermined system acquisition process. In a preferred embodiment, wireless communication systems in the geographical area 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 an alternative embodiment, candidate list 104b includes other data such as corresponding acquisition parameters and preference information for the selected systems. Candidate list 104b is stored in an initial order of priority (eg, from the most preferred system to the least preferred system) as determined by the preferred system acquisition process. Although system selection using a PRL is shown, It will be appreciated that other system acquisition procedures may be used in accordance with the preferred embodiment. For example, in an alternative embodiment, the system acquisition process includes selecting a system group from the MRU 104a or other stored system lists.

As is known, the system table 100 specifies the preferred system acquisition order used by the mobile station 2 during system acquisition / registration attempts. However, this system acquisition order is not always the most efficient system selection order for acquiring and registering a wireless communication system. The selected order specified by the system table 100 is typically determined by the mobile station's wireless service provider based on factors not related to the likelihood that each listed system will be obtained by the mobile station 2. For example, each system preferably uses the system, the quality of the communication service provided by the system, the protocol used by the system, support for unique features, and the mobile station 2 is a subscriber of the wireless communication system. Are determined using the same criteria as listed as

In order to improve 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 based on the result of the analysis, acquires the system acquisition signal. Adjust (step 204). In the most preferred embodiment, the analysis of the received signal comprises measuring the received signal strength Rx of each system. In operation, searcher 94 steps through the systems identified in candidate list 104b stored in memory 24. In an alternative embodiment, the candidate list is sent from the system determination unit 96 to the searcher 94. For each listed system, the searcher 94 instructs the transceiver 84 to switch to the corresponding channel of the system. The received signal strength is specified and stored in the candidate list 104b. If the received signal strength measurement is relatively low, then it is unlikely that the candidate system will be available for acquisition. If the received signal strength measurement is relatively high, the probability that a candidate system can be obtained increases. It will be appreciated that signal strength measurements for a group of systems can be completed in significantly less time than attempting to acquire and register each system in the group. In an alternative embodiment, other tests are performed on the received signal to assist in determining the likelihood that the candidate system is likely to be obtained.

In a first alternative embodiment, analysis of the received signal includes determining the likelihood that the received signal is a CDMA signal. In this embodiment, the system determination unit 96 directs the searcher 94 to measure the signal to noise ratio E _c / I _o , where E _c is the strength of the received signal and I _o is received on the channel. Total thermal noise. In a CDMA system, this measurement provides an indication of the portion of the received signal that is available. If the ratio E _o / I _C is relatively large, the system is likely to be obtained. The ratio E _o / I _C provides an indication that the signal is more reliable than the measured raw strength of the signal.

In the second selected embodiment, the system determination unit 96 and the searcher 94 support multiple test modes and acquisition methods and are adapted to use one or more forms of analysis or a combination thereof. The test mode is determined by user preference, the configuration of the mobile station, the current operating state of the mobile station or other criteria. The searcher 94 preferably operates in accordance with instructions received from the system determination unit 96, and the system determination unit 96 is adapted to send candidate system test instructions and system acquisition instructions. The candidate system test indication includes a candidate list, an identifier of a test to be performed on each candidate system, and parameters for identifying the minimum threshold met by each system. The searcher 94 performs the received instructions and returns to candidate systems that meet the testing conditions. In the preferred embodiment, the searcher 94 changes the candidate list stored in memory. System determination unit 96 analyzes the test results and sends a system acquisition indication to searcher 94 including parameters identifying candidate lists.

In step 204, the selected system group is reprioritized based on the analysis to provide a more efficient system acquisition order. In a preferred embodiment, all systems are stored such that the systems most likely to be obtained are selected first. In a first alternative embodiment, multiple selected systems have the same level of preference. At each level of preference, the selected systems are stored from the system most likely to be obtained using the specified signal strength to the system most unlikely to be acquired. In a second alternative embodiment, the preference information for each selected system is adjusted based on the test measurement. For example, the relative preference of systems with signal strength measurements above the first threshold is adjusted upward, while the relative preference of systems with signal strength below the second threshold is adjusted downward. The group of selected systems is stored using the adjusted preference information. In a third alternative embodiment, systems with tested signal quality below the threshold are removed from the group of selected systems. For example, candidate systems with corresponding measurement signal strength below −90 db are removed from the candidate list. Another criterion is used to remove or classify candidate systems. For example, the weighting factor is used in consideration of the measured signal strength, whether the system has been used recently and the degree of preference, and other information.

After the group of selected systems has been reprioritized, the mobile station 2 attempts to acquire and register one of the in-group wireless communication systems. In step 206, the system with the highest level of priority is selected from the candidate list 104b. In a preferred embodiment, there is a high likelihood that the acquisition / registration attempt will be successful based on measured signal quality, such as signal strength measurement, with a relatively high level of preference. At step 208, acquisition and registration of the selected system is attempted. Any system acquisition method is used, including known conventional system acquisition methods. In the preferred embodiment, the mobile station 2 is adapted to a CDMA system. To obtain the CDMA system, the searcher 94 causes the transceiver to switch to the communication channel of the selected CDMA system to receive the pilot signal. The searcher 94 attempts to verify the received pilot signal by various pseudo random noise (PN) offsets in the received signal until it matches. Once the pilot signal is obtained, processing circuit 80 receives the information for the forward CDMA channel and the phase reference for signal demodulation. Next, the processing circuit 80 attempts to obtain a sync channel associated with the identified pilot channel. The synchronization channel transmits basic system information such as unique SID / NID and synchronization information of the wireless communication system and network being transmitted. The processing circuit 80 adjusts its timing according to the received information and switches the paging channel of the base station. The paging channel is used by the local base station of the current communication system to communicate with the mobile station when the mobile station 2 is not assigned to a traffic channel. Through the paging channel, the base station notifies the mobile station 2 of input messages, such as notification of an incoming telephone call or a received voicemail message.

If the acquisition / registration attempt is successful, the selected system is used by the mobile station 2 for wireless communication. If the acquisition / registration attempt is unsuccessful, then the wireless communication system with the next highest priority is selected from the candidate list in step 212 and controlled for the next acquisition / registration attempt and returns to step 208. If searcher 94 cannot obtain the selected system (step 210), searcher 94 will attempt to acquire each of the remaining systems in the order of selection until the wireless communication system is acquired or candidate systems are consumed. In an alternative embodiment, if the acquisition / registration attempt is successful at step 210, the process returns to step 200 for selection of a group of systems in the current geographic area that is more desirable than the selected system.

An optional system acquisition sequence is shown in the flowchart of FIG. 6. In step 250, a first system is selected according to the system acquisition process. Any system acquisition procedure is 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 a system is likely to be acquired (step 254), an attempt is made to acquire and register the system selected in step 256. In a preferred embodiment, the system will be obtained if the measured signal quality exceeds a predetermined threshold. If the system is unlikely to be acquired, the next system is selected according to the system acquisition process at step 260. If the acquisition / registration attempt is successful (step 258), the mobile station 2 uses the system selected for future wireless communication services. If the acquisition / registration attempt is not successful, then the next wireless communication system is selected in step 260 and returns to step 252.

Description of the preferred embodiments of the method and apparatus for the efficient selection and acquisition of a wireless communication system will be apparent to those skilled in the art that certain advantages within the described system can be achieved. It will be appreciated that various modifications, adaptations, and alternative embodiments are possible within the scope and spirit of the invention.

The scope of the invention is defined by the following claims.

Claims (23)

A process of acquiring a system in a mobile station for storing a list of wireless communication systems, Selecting a group of wireless communication systems from a list according to a predetermined system acquisition process, wherein the group of wireless communication systems has a first system acquisition order; Measuring signal quality for each of the selected systems; Reprioritizing the group of wireless communication systems in accordance with the measured signal quality, wherein the reprioritized group of wireless communication systems has a second system acquisition order; And Attempting to obtain a wireless communication system with the highest priority according to the second system acquisition order. 2. The method of claim 1, wherein the list of wireless communication systems is a preferred roaming list that includes a geographic area identifier, and wherein selecting a group of wireless communication systems includes determining a current geographic area of the mobile station and the mobile station. Selecting the listed wireless communication systems having a geographic area identifier corresponding to the current geographic area of; Wherein the first system acquisition order is based on a relative order of the selected wireless communication systems in the preferred roaming list. 3. The wireless communication system of claim 2, wherein each wireless communication system identified in the preferred roaming list has a corresponding level of preference, at least two of the selected systems having the same level of preference, The reprioritizing step includes positioning selected systems that share the same level of desirability that has been measured and classifying the located systems by measured signal strength. 4. The method of claim 3, wherein each wireless communication system identified in the preferred roaming list has a corresponding preference level, wherein the re-prioritization step is: For each selected system, adjusting a corresponding preference level based on the corresponding measured signal strength, wherein the adjusted preference criteria is stored within a group of wireless communication systems; And Classifying the group of wireless communication systems by the adjusted preference levels. 2. The method of claim 1, wherein reprioritizing comprises removing the selected system if the selected system from the group does not meet its minimum measured signal quality. The method of claim 1, wherein measuring the signal quality comprises calculating a ratio E _c / I _o of the received signal. As a mobile station, A memory for storing a preferred roaming list comprising a first plurality of system identifiers and corresponding acquisition parameters; And Processing circuitry adapted to select wireless communication systems from the preferred roaming list according to a predetermined system acquisition process, wherein the selected wireless communication systems have a corresponding system acquisition order; The processing circuitry is adapted to specify a signal quality of each selected system and to modulate the system acquisition order based on the measured signal qualities, wherein the modulated system acquisition order increases the efficiency of the system acquisition process. Lee Dong-guk. 8. The system of claim 7, wherein the selected wireless communication systems have corresponding preference criteria, And the processing circuit is adapted to adjust the corresponding preference criteria of the selected system if the corresponding signal strength measurement exceeds the first threshold and classify the selected wireless communication systems using the adjusted preference criteria. 8. The mobile station of claim 7, wherein the measured signal quality for each system comprises a signal-to-noise ratio of the received signal, wherein the signal-to-noise ratio corresponds to the likelihood that the system is obtained. A method for acquiring a wireless communication system in a multi-mode mobile station adapted to operate in a CDMA and AMPS method, the method comprising: Analyzing a signal received on a channel in accordance with a candidate communication system; Determining a possibility that the candidate communication system is available for acquisition by the mobile station based on the analysis of the received signal; And Attempting to obtain the candidate communication system if the candidate communication system is available for acquisition. 12. The method of claim 10, wherein analyzing comprises switching channels associated with the candidate communication system and testing signal quality of the received signal. 12. The communication system of claim 11, wherein the mobile station comprises a table of known communication systems, each known communication system having a relative preference, and wherein the candidate communication system is known in accordance with a predetermined system acquisition process. Method selected from the table of the. The method of claim 11, wherein the tested signal quality is a received signal strength measurement. 12. The method of claim 11, wherein the tested signal quality is a signal to noise ratio of the received signal. 12. The method of claim 11, wherein the candidate communication system is likely to be usable if the measured signal quality exceeds a predetermined threshold. 12. The method of claim 11, wherein the method further comprises selecting a set of candidate communication systems, wherein the analyzing and determining steps are repeated for each candidate communication system in the set, and the attempting step is most likely to be obtained. Method performed in these high candidate communication systems. 17. The method of claim 16, further comprising classifying the candidate communication systems in an order of measured signal quality, the sorted order defining an acquisition order for a set of candidate communication systems. An integrated circuit in a wireless device, A system determination unit adapted to identify candidate communication systems in a current geographic area of the wireless device; And A searcher coupled to the system determination unit and adapted to analyze signal quality of at least one of the identified wireless communication systems to determine a possibility that the wireless communication systems are likely to be obtained. 19. The integrated circuit of claim 18, wherein the searcher measures the strength of a received signal 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 _o of the received signal for each identified wireless communication system. 19. The system of claim 18, wherein the integrated circuit further comprises a memory coupled to the system determination unit, the memory storing a list of known communication systems, each known communication system having associated geographic regions and relative preferences. Has, A system analyzed by the searcher is selected from the system table by the system determining unit. 19. The system of claim 18, wherein the system determination unit is adapted to send an indication to the searcher, the instruction including a test identifier, In response to the received indication, the searcher analyzes the signal quality of at least one of the identified wireless communication systems using the test method identified by the test identifier. 23. The integrated circuit of claim 22, wherein the sent indication further comprises a threshold, wherein the searcher sends a notification message to the system determination unit when at least one analyzed signal quality exceeds the threshold.