HK1114729A - Method and apparatus for handling roaming lists in a wireless communication system - Google Patents

Description

Method and apparatus for processing roaming list in wireless communication system

Background

FIELD

The present invention relates generally to the processing of roaming lists in wireless communication systems, and more particularly to updating preferred roaming lists and coordinating different protocol versions between a wireless communication network and remote users.

Background

A protocol is a rule governing the transmission and reception of information over a data communication link. Protocols are detailed in a set of standards that ensure that different network products can work together. Any product using a given protocol should work with other products using the same protocol. In a wireless communication system, protocols define various architectural layers of the system. As protocols and standards are revised, system components using older versions of the protocols and standards may become incompatible with system components having newer capabilities. Various approaches are used to address this incompatibility, each of which is specific to a protocol and/or standard.

An incompatible domain often arises when protocols that traditionally govern voice-dominated communications are extended to also govern high data rate transmissions. For example, a remote user of one service provider, the primary provider, may access other service providers, the secondary provider, while outside the service area of the primary provider. This process is called roaming, which is facilitated by the use of a roaming list maintained by the remote user. The roaming list is updated by the service provider when the list changes, e.g., a new relationship with another service provider. The format of the roaming list and the format of the transmission for updating the roaming list may be specified by protocols in the standard. The addition of high data rate services or other new services may require changes in the format of the roaming list and changes in the method of updating the roaming list. Such protocol revisions may result in incompatibility difficulties between the network and the remote user. When the protocol revision of the remote user is different from that of the network, the accuracy of the roaming list and the availability to the remote user are jeopardized.

Accordingly, there is a need in the art for an efficient procedure for configuring, maintaining and updating a preferred roaming list over different transport protocol versions in a wireless communication system.

SUMMARY

The disclosed embodiments address the above stated needs by providing a method and apparatus for updating a roaming list in which a roaming list format identifier is provided to a remote user that identifies a protocol version supported by a network. The roaming list format identifier acts to request an old version of the protocol or to request the format currently stored at the remote user. In one embodiment, the old version is the preferred roaming list and the new version is the extended preferred roaming list. Upon receiving the roaming list format identifier and the configuration request, the remote user receiving the roaming list format identifier sends an error message if the format identifier is not compatible with the protocol version currently used by the remote user. Similarly, if the format identifier is compatible with the protocol version used by the remote user, the remote user sends configuration information. An error handling message is provided when roaming list protocols within various elements in the system are incompatible.

Brief description of the drawings

Fig. 1 is a communication system.

Fig. 2-5 are timing diagrams illustrating a process for updating a preferred roaming list for various configurations of a remote user and network.

Fig. 6 is a flow chart of a method of updating a preferred roaming list.

Fig. 7 is a mobile station.

Detailed Description

The word "exemplary" is used herein to mean "serving as an example, instance, or illustration. Any embodiment described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other embodiments.

Wireless communication systems are widely deployed to provide various types of communication such as voice, data, and so on. These systems may be based on Code Division Multiple Access (CDMA), Time Division Multiple Access (TDMA), and some other modulation techniques. CDMA systems provide certain advantages over other types of systems, including increased system capacity.

The CDMA System may be designed to support one or more CDMA standards, such as (1) "TIA/EIA-95-B mobile Station-Base Station Compatibility Standard for Dual-Mode Wideband spread spectrum Cellular System (TIA/EIA-95-B mobile Station-Base Station Compatibility Standard for Dual-Mode Wideband spread spectrum Cellular System" (IS-95 Standard), (2) the Standard provided by the association named "third generation mobile communication partnership project" (3GPP), and included in a series of documents (WCDMA Standard) including document numbers 3G TS 25.211, 3G TS 25.212, 3G TS 25.213, and 3G TS 25.214, (3) the Standard included in a series of documents provided by the association named "third generation mobile communication partnership project 2" (3GPP2), including "c.2000-System for CDMA spread spectrum systems (Layer 2-Physical Standard for CDMA 2.0002.s.2 for CDMA) CDMA2000 SpreadSpectrum Systems), "C.S0005-A higher Layer (Layer 3) Signaling Standard for CDMA2000 spread spectrum Systems (C.S0005-A Upper Layer (Layer 3)" and "C.S0024 CDMA2000 High Rate Packet Data Air Interface Specification (C.S0024 CDMA2000 High Rate Packet Data Air Interface Specification)" (CDMA2000 Standard), (4) "TIA/EIA-IS-CDMA 2000 High Rate Packet Data Air Interface Specification (TIA/EIA-IS-856 CDMA2000 High Rate Packet Data Air Interface Specification)" (IS-856 Standard), and (IS 5) some other standards.

Cellular communication system users typically have a service agreement with the cellular provider. Systems operated by cellular providers may cover limited geographic areas. When the user travels outside the geographic area, the service may be provided by another service provider under a roaming agreement. There will typically be more than one service provider in a particular area, so the user can choose which service provider to roam with. As the growth of cellular communication systems has proliferated, networks of cellular systems have been organized under public service providers, or with contractual agreements between service providers. Roaming fees are minimized or eliminated when a user transitions between systems that are parties to such agreements. Thus, modem mobile stations typically use a Preferred Roaming List (PRL) that contains information about the preferred system for roaming and various parameters needed to communicate with it. The PRL may be pre-programmed in the mobile station when initiating service. Alternatively, the PRL may be programmed by over-the-air data transfer. This programming is described in "TIA/EIA-683-B broadcast Transmission service Provisioning of Mobile services in Spread Spectrum Systems" (TIA/EIA-683-B Over-the-Air service provisioning of Mobile Stations in Spread Spectrum Systems), which is a standard compatible with the wireless communication Systems described above.

Fig. 1 is a diagram of a wireless communication system 100 in accordance with one embodiment that supports a number of users and is capable of implementing various aspects of the invention. . System 100 may be designed to support one or more CDMA standards and/or designs (e.g., the W-CDMA standard, the IS-95 standard, the CDMA2000 standard, the IS-856 standard). For simplicity, the system 100 is shown to include three base stations 104 in communication with two mobile stations 106. The base stations and their coverage areas are often collectively referred to as a "cell". In an IS-95 system, a cell may include one or more sectors. In the W-CDMA specification, each sector of a base station and the sector's coverage area is referred to as a "cell". As used herein, the term "base station" may be used interchangeably with the term "access point". The term "mobile station" may be used interchangeably with the terms "User Equipment (UE)", "subscriber unit", "subscriber station", "access terminal", "remote terminal" or other corresponding terms known in the art. The term mobile station includes fixed wireless applications.

Depending on the CDMA system implemented, each mobile station 106 may communicate with one (or possibly more) base stations 104 on the forward link at any given moment, and may communicate with one or more base stations on the reverse link depending on whether the mobile station is in soft handoff. The forward link (i.e., downlink) refers to transmission from the base station to the mobile station, and the reverse link (i.e., uplink) refers to transmission from the mobile station to the base station. The word "exemplary" is used exclusively in this disclosure to mean "serving as an example, instance, or illustration. Any embodiment described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other embodiments.

Fig. 2-5 illustrate roaming list updates for various configurations. For these examples, the system supports the protocols detailed in IS-683-B, and may support newer versions of these protocols. For example, as a new version of the PRL, an extended PRL is supported. The extended PRL includes information for high data rate services in addition to information supported by the PRL. The extended PRL is extensible to other communication systems.

Fig. 2 illustrates call processing in which both a remote unit or Mobile Station (MS) and a network identified as a broadcast delivery service provisioning function (OTAF) support an old version Preferred Roaming List (PRL). OTAF is a network infrastructure element such as a Base Station (BS) or Base Station Controller (BSC). For simplicity, the old version is referred to as "PRL" and the new version is referred to as "E-PRL". Note that alternate embodiments may implement any of a variety of naming conventions to identify the previous version from the later version in the roaming list. Similarly, alternate embodiments may implement more than two versions. In the scenario of fig. 2, the OTAF sends a protocol capability request to the MS. The MS response indicates PRL is supported. The OTAF then sends a preferred roaming list System Selection (SSPR) configuration request message. Thus, the SSPR configuration request includes a BLOCK _ ID field. The BLOCK _ ID field is used to identify the parameter BLOCK requested in this message. In this case, the BLOCK _ ID field is set to the hexadecimal value 0x00 (or binary value 0000000), requesting the configuration, i.e., dimension, of the old version PRL. Since the MS supports only the old version PRL, the MS responds with the configuration information of the PRL. The OTAF then determines whether the PRL at the MS needs to be updated. If this is the case, the OTAF downloads the new information for storage in the MS.

Fig. 3 shows a case where OTAF supports E-PRL, and the MS supports PRL only. In this case, the OTAF checks the performance of the MS and in response sends an SSPR configuration request with the BLOCK _ ID field set to 0x00 corresponding to the PRL. Note that OTAF can handle both PRL and E-PRL, and thus can interface with an MS that can handle PRL or E-PRL. In this case, the MS can only support PRL; the OTAF requests a PRL configuration. The MS responds and processing continues as in fig. 2.

Fig. 4 shows a case where OTAF supports PRL, and the MS supports PRL and E-PRL. In this case, when the OTAF requests the capability information, the MS sends a response identifying both PRL and E-PRL support. OTAF cannot process E-PRL information. Note that although the MS can support both PRL and E-PRL, only one can be supported at a time. The OTFA then requests configuration information. The MS sends the configuration information in response. If the SSPR configuration request message contains a request for a preferred roaming list dimension parameter BLOCK (BLOCK _ ID ═ 00000000), and if the mobile station supports SSPR _ P _ REV greater than or equal to "00000011" and stores the preferred roaming list associated with SSPR _ P _ REV greater than or equal to "00000011", then the mobile station should set the RESULT _ CODE in the SSPR configuration response message to "00100011": reject-PRL format mismatch. The mobile station should include a parameter BLOCK whose BLOCK _ LEN field is set to 0. In other words, if the OTAF only supports the old version, while the MS supports the new version, and currently stores a roaming list in a new format, the MS sends an error message to the OTAF. If the current roaming list stored in the MS is in PRL format, the OTAF receives the PRL configuration information and responds accordingly. However, if the current roaming list in the MS is in E-PRL format, the OTAF receives configuration information that it cannot handle. To avoid such problems, in this embodiment, the OTAF sends an SSPR configuration request with a BLOCK _ ID equal to 0x00, indicating that the OTAF wishes to receive PRL configuration information. In this manner, if the MS stores the PRL format, the PRL configuration is sent to the OTAF. Otherwise, if the MS stores the E-PRL format, an SSPR configuration response with an error code is sent to the OTAF. At this point, the OTAF is notified of the compatibility issue and determines a corrective strategy specific to the implementation.

Fig. 5 shows the final scenario where both the OTAF and the MS support a new version of E-PRL. The OTAF determines the capabilities of the MS and identifies the MS as supporting both PRL and E-PRL. At this point, the OTAF does not know the format currently stored in the MS. For example, although the MS supports E-PRL, the MS may be changed from a service provider that supports only PRL. Thus, the current format of the roaming list in the MS may be PRL or E-PRL. OTAF wishes to update to E-PRL if available. The OTAF sets the BLOCK _ ID field in the SSPR configuration request message to 0x 02. This indicates to the MS that the OTAF desires SSPR configuration information regarding the current format of the roaming list. The MS responds with configuration information, PRL dimension or E-PRL dimension, stored in the MS, based on the current format.

According to an exemplary embodiment, an MS supporting both the new and old versions uses an extended memory storage area to store roaming lists. Either format may be stored in the extended memory storage area. Table 1 provides the block of E-PRL dimension parameters as stored in the MS. The PARAM _ DATA field of the extended preferred roaming list dimension parameter block consists of the fields listed in the table.

TABLE 1 extended preferred roaming List dimension parameter Block

Field(s)	Length (position)
		MAX_PR_LIST_SIZE	16

CUR_PR_LIST_SIZE	16
		PR_LIST_ID	16
CUR_SSPR_P_REV	8
		SSPR _ P _ REV specific field	Variable

If the CUR _ SSPR _ P _ REV is "00000001", the SSPR _ P _ REV specific fields also include the following fields:

RESERVED (Retention)	1
		NUM_ACQ_RECS	9
NUM_SYS_RECS	14

If the CUR _ SSPR _ P _ REV is "00000011", the SSPR _ P _ REV specific fields also include the following fields:

NUM_ACQ_RECS	9
		NUM_COMMON_SUBNET_RECS	9
NUM_EXT_SYS_RECS	14

the following definitions explain the various fields listed in table 1.

MAX _ PR _ LIST _ SIZE — maximum preferred roaming LIST SIZE.

The mobile station sets the field to mobile in octet format

Preferred roaming LIST (PR _ LIST) that a station can support_S-P) Is/are as follows

The largest dimension.

CUR _ PR _ LIST _ SIZE — current preferred roaming LIST SIZE.

The mobile station sets this field to current in octet format

The size of the preferred roaming list.

PR _ LIST _ ID — preferred roaming LIST identification.

The mobile station sets this field to be the preferred roaming list by the base station

Table (PR _ LIST)_S-P) Identified by an assigned preferred roaming list

The value is obtained.

CUR _ SSPR _ P _ REV — agreement revision of the mobile station's current preferred roaming list.

The mobile station sets this field to be associated with the current preferred roaming list

The value of the associated SSPR _ P _ REV.

RESERVED-RESERVED bit.

The mobile station sets this field to "0".

NUM _ ACQ _ RECS-number of acquisition records.

The mobile station sets this field to be included in the currently preferred roaming

Number of acquisition records in ACQ _ TABLE field of list

And (4) counting.

NUM _ SYS _ RECS-the number of system records.

The mobile station sets this field to be included in the currently preferred roaming

Number of system records in the SYS _ TABLE field of the list.

NUM _ COMMON _ SUBNET _ RECS-number of records in the COMMON sublist.

This field is set to the number of records contained in the common sublist

And (4) counting.

NUM _ EXT _ SYS _ RECS-number of extended system records

The mobile station sets this field to be included in the currently preferred roaming

Extended systems in EXT _ SYS _ TABLE field of List

And recording the number.

Fig. 6 is a flow diagram illustrating a process of updating a roaming list, according to one embodiment. As shown, the process 400 begins by the MS receiving a capability request message at step 402. The MS responds by sending the capability information at step 404. In step 406, the MS receives a configuration request message from the OTAF. The configuration request message includes a BLOCK _ ID field. Based on the value of the BLOCK _ ID field, the MS determines an appropriate response at decision diamond 408. If the OTAF requests current information about which format the MS is currently using for the roaming list, the process continues to step 410. The MS sends back a configuration message of the stored current roaming list. If the BLOCK _ ID requests a PRL configuration message and the MS does not support E-PRL, the process continues to step 416 to send the PRL configuration information to the OTAF. If the BLOCK _ ID requests PRL configuration information and the MS does support E-PRL, the MS determines in which format (PRL or E-PRL) the roaming list is currently stored. If the list is stored in PRL format, the process continues to step 416. Otherwise, if the list is stored in E-PRL format, the process continues to step 418 to send a response message with an error code to the OTAF.

Fig. 7 illustrates one embodiment of a mobile unit 500. For simplicity, only groupings of components are shown. The signal is received at an antenna 510 and transmitted to a receiver 520 where it is amplified, down-converted, sampled, and demodulated. Various techniques for receiving CDMA signals are known in the art. In addition, the principles of the present invention are also equally applicable to wireless communication systems using air interfaces other than CDMA-based air interfaces. The receiver 520 is in communication with a Central Processing Unit (CPU) 530. The CPU 530 may be a microprocessor or a Digital Signal Processor (DSP), or one of various processors known in the art. The CPU 530 communicates with a memory 540, which is shown as containing a roaming list 560. The roaming list 560 may be programmed by broadcast transmission programming in conjunction with the antenna 510 and receiver 520, or the data for the roaming list may enter the CPU 530 from other inputs (not shown). CPU 530 is also coupled to transmitter 550 to transmit messages, data, voice, etc. using any transmission technique known in the art. Transmitter 550 is connected to antenna 510 for transmission to a base station, such as base station 104. While the mobile station is roaming, the receiver 520 and transmitter 550, in conjunction with the antenna 510, may be used to communicate with one or more systems identified in the roaming list 560. The mobile unit 500 is a hybrid unit that supports both PRL and E-PRL. Memory storage locations in the PRL560 may also be used to store E-PRL information. Roaming list decision unit 570 receives a roaming list format identifier, such as the information contained in the BLOCK _ ID discussed above. Roaming list decision unit 570 then determines the appropriate response as detailed in the process of fig. 6. Roaming list decision unit 570 also controls the storage of roaming lists in roaming list 560. The roaming list decision unit 570 provides the configuration information to be transferred to the CPU 530.

Those of skill in the art would understand that information and signals may be represented using any of a variety of different technologies and techniques. For example, data, instructions, commands, information, signals, bits, symbols, and chips that may be referenced throughout the above description may be represented by voltages, currents, electromagnetic waves, magnetic fields or particles, optical fields or particles, or any combination thereof.

Those of skill would further appreciate that the various illustrative logical blocks, modules, circuits, and algorithm steps described in connection with the embodiments disclosed herein may be implemented as electronic hardware, computer software, or combinations of both. To clearly illustrate this interchangeability of hardware and software, various illustrative components, blocks, modules, circuits, and steps have been described above generally in terms of their functionality. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the overall system. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present invention.

The various illustrative logical blocks, modules, and circuits described in connection with the embodiments disclosed herein may be implemented or performed with a general purpose processor, a Digital Signal Processor (DSP), an Application Specific Integrated Circuit (ASIC), a Field Programmable Gate Array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A general purpose processor may be a microprocessor, but in the alternative, the processor may be any conventional processor, controller, microcontroller, or state machine. A processor may also be implemented as a combination of computing devices, e.g., a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration.

The steps of a method or algorithm described in connection with the embodiments disclosed herein may be embodied directly in hardware, in a software module executed by a processor, or in a combination of the two. A software module may reside in RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art. An exemplary storage medium is coupled to the processor such the processor can read information from, and write information to, the storage medium. In the alternative, the storage medium may be integral to the processor. The processor and the storage medium may reside in an ASIC. The ASIC may reside in a user terminal. In the alternative, the processor and the storage medium may reside as discrete components in a user terminal.

The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims (14)

1. A method of updating a roaming list with a communication entity, comprising:

storing a roaming list in a format;

receiving a configuration request from the communication entity, the configuration request identifying the format of the roaming list;

sending the configuration information of the format to the communication entity;

updating the roaming list if the communication entity supports the format.

2. The method of claim 1, further comprising:

providing the roaming list in the format, the roaming list selected from the group consisting of a Preferred Roaming List (PRL) and an extended preferred roaming list (E-PRL).

3. The method of claim 1, further comprising:

responding to a capability request from the communication entity, the capability request requesting support with respect to the roaming list, prior to the receiving the configuration request.

4. The method of claim 1, further comprising:

if the communication entity does not support the first format, an error message is sent to the communication entity.

5. A method for updating a roaming list of a communication entity, comprising:

receiving configuration information in a format of a roaming list from the communication entity;

updating the roaming list of the communication entity if the format of the roaming list is supported.

6. The method of claim 5, further comprising:

sending a capability request to the communication entity, the capability request requesting support with respect to the roaming list, prior to the receiving the configuration request.

7. The method of claim 5, further comprising:

providing the roaming list in the format, the roaming list selected from the group consisting of a Preferred Roaming List (PRL) and an extended preferred roaming list (E-PRL).

8. A communication device, comprising:

the storage module stores a roaming list adopting one format;

a receiving module that receives a configuration request from the communication entity, the configuration request identifying the format of the roaming list;

the sending module is used for sending the configuration information of the format to the communication entity;

an update module that updates the roaming list if the communication entity supports the format.

9. The communications apparatus of claim 8, further comprising:

a provisioning module that provisions the roaming list in the format, the roaming list being selected from the group consisting of a Preferred Roaming List (PRL) and an extended preferred roaming list (E-PRL).

10. The communications apparatus of claim 8, further comprising:

a response module that responds to a capability request from the communication entity, the capability request requesting support with respect to the roaming list.

11. The communications apparatus of claim 8, further comprising:

an error message sending module that sends an error message to the communication entity if the communication entity does not support the format.

12. An infrastructure apparatus capable of updating a roaming list of a communication entity, comprising:

a receiving module that receives configuration information of a format of a roaming list from the communication entity;

an update module that updates the roaming list of the communication entity if the format of the roaming list is supported.

13. The infrastructure equipment of claim 12 further comprising:

a sending module that sends a capability request to the communication entity, the capability request requesting support with respect to the roaming list.

14. The infrastructure equipment of claim 12 further comprising:

a provisioning module that provisions the roaming list in the format, the roaming list being selected from the group consisting of a Preferred Roaming List (PRL) and an extended preferred roaming list (E-PRL).