Wireless access network and method for handover of mobile terminals in idle mode

Embodiments of a wireless access network and methods for maintaining current location information for mobile terminals in idle mode are generally described herein. Other embodiments may be described and claimed.

TECHNICAL FIELD

Some embodiments of the present invention pertain to wireless communications. Some embodiments of the present invention pertain to wireless access networks. Some embodiments of the present invention pertain to idle mode and paging operations of mobile terminals.

BACKGROUND

Wireless access networks can be used to communication voice data, such as voice over internet protocol (VoIP), as well other time-sensitive traffic flows, with mobile terminals. These wireless access networks need to quickly determine the current location of a mobile terminal to meet the requirements of the traffic flow. During active mode, the locations of mobile terminals are updated and maintained by a home agent in the network. However when mobile terminals are in idle mode, their locations are not continually updated. For some time-sensitive applications, the delay associated with locating a mobile terminal in idle mode may be excessive.

Thus, there are general needs for wireless access networks and methods for handover that allow a mobile station in idle mode to be located easier. There are also general needs for wireless access networks that can page a mobile terminal for time-sensitive applications, such as VoIP and push-to-talk (PTT) applications, without excessive delay when the mobile terminal is in idle mode.

DETAILED DESCRIPTION

The following description and the drawings sufficiently illustrate specific embodiments of the invention to enable those skilled in the art to practice them. Other embodiments may incorporate structural, logical, electrical, process, and other changes. Examples merely typify possible variations. Individual components and functions are optional unless explicitly required, and the sequence of operations may vary. Portions and features of some embodiments may be included in, or substituted for, those of other embodiments. Embodiments of the invention set forth in the claims encompass all available equivalents of those claims. Embodiments of the invention may be referred to herein, individually or collectively, by the term “invention” merely for convenience and without intending to limit the scope of this application to any single invention or inventive concept if more than one is in fact disclosed.

FIG. 1illustrates a wireless communication network in accordance with some embodiments of the present invention. Wireless communication network100may include core service network102and a plurality of access service networks104, shown as access service network104A, access service network104B, access service network104C and access service network104D. Access service networks104route communications between core service network102and mobile stations, such as mobile station112, allowing mobile stations, such as mobile station112, to receive communications from external networks106and to send communications to external networks106.

Each access service network104may include foreign agent114and paging controller116for communicating with other access service networks and/or communicating with core service network102. Access service networks104may also include base stations for communicating radio-frequency signals with the mobile stations, such as mobile station112. Each of the base stations may be associated with one of paging groups (PGs)110. Paging groups110may comprise a cluster of base stations and may be administered by an associated one of paging controllers116.

In some embodiments, some access service networks104, such as access service network104A, may include proxy mobile client120. Proxy mobile client120may serve as a proxy for mobile station112and may perform certain network operations on behalf of mobile station112. These embodiments are discussed in more detail below. Although proxy mobile client120is illustrated in access service network104A, any of access service networks104may include one or more proxy mobile clients for mobile stations serviced by access service networks104.

In some embodiments, access service networks104may include an access service network gateway (not separately illustrated) for communicating with core service network102. Each access service network gateway may include a foreign agent, such as one of foreign agents114, a paging controller, such as one of paging controllers116and/or a proxy mobile client, such as proxy mobile client120. In some embodiments, one or more of the functional elements of an access service network gateway may be distributed among the various physical entities, although the scope of the invention is not limited in this respect.

Core service network102may include home agent118and authentication, accounting, and administration (AAA) server122. Home agent118may store an internet protocol (IP) address of foreign agent114of access service network104where mobile station112is currently located. In this way, data101destined for mobile station112that is received at core service network102may be routed to the proper one of access service networks104based on the information in home agent118.

In accordance with some embodiments, mobile station112may operate in either active mode or idle mode. During active mode, mobile station112may be actively communicating within one of access service networks104. During idle mode, mobile station112may be in a lower-power state and may be listening for pages and/or broadcast channels within one of access service networks104. During active mode, the IP address of mobile station112with respect to each of access service networks104may be updated and maintained by home agent118. In active mode, the location of mobile station112with respect to a particular base station within one of paging groups110may also be known because mobile station112may be actively engaging in communications through the base station. However in conventional networks, the location of mobile station112with respect to access service networks104may not be known when mobile station112is in idle mode because mobile station112may not be actively engaging in communications. When mobile station112changes access service networks104, the IP address of mobile station112may need to be changed or updated.

During idle mode, mobile station112may receive an incoming message, such as a page, to indicate to mobile station112that there is data for mobile station112or that there is an incoming call for mobile station112. In response to the page, mobile station112may transition from idle mode to active mode to receive and to process the data. The use of an updated IP address for mobile station112while in idle mode may allow paging and connection establishment latency to be reduced, although the scope of the invention is not limited in this respect. This may help support the requirements for time-sensitive applications such as VoIP and PTT.

In accordance with some embodiments, mobile station112may not necessarily have the capability to perform certain network operations, such as mobile internet protocol (MIP) registration request and MIP registration response operations, for updating its IP address as it changes between paging groups110of different access service networks104. In these embodiments, proxy mobile client120may serve as a proxy for mobile station112and may perform certain network operations, such as MIP registration request and MIP registration response operations, on behalf of mobile station112. In these embodiments, the infrastructure of network100may be proxy mobile IP (PMIP) based and proxy mobile client120may be a PMIP client for mobile station112, although the scope of the invention is not limited in this respect.

In some embodiments, the infrastructure of network100may also support client mobile IP (CMIP) operations, although the scope of the invention is not limited in this respect. In these embodiments that support CMIP operations, some mobile stations may have capability to perform MIP registration request and MIP registration response operations, although the scope of the invention is not limited in this respect.

In accordance with some embodiments, a handover for mobile station112may occur when mobile station112reaches a new paging group110while mobile station112is in idle mode. In the examples discussed herein, an anchor paging controller, illustrated as anchor paging controller116B, may refer to the paging controller116of the access service network104where mobile station112was last registered, and a relay paging controller, illustrated as relay paging controller116D, may refer to a paging controller116of an access service network104where mobile station112may have relocated. In these embodiments, a location update message may be sent to relay paging controller116D within access service network104D where mobile station112now resides. In these embodiments, the location update message may include the network address of anchor paging controller116B. Relay paging controller116D may contact anchor paging controller116B to inform anchor paging controller116D that mobile station112has changed locations while in idle mode. In these embodiments, anchor paging controller116B may maintain the latest location information for mobile station112(e.g., in terms of one of paging groups110) while mobile station112is in idle mode.

When anchor paging controller116B receives a location update request message from relay paging controller116D, it may compare the address of relay paging controller116D it received in the message with the address of the last paging controller116that it had stored in its location register for mobile station112. If the two addresses match, then mobile station112has switched paging groups110within the same access service network104. In this situation, no action is needed to update the location information for mobile station112. In this situation anchor paging controller116B and relay paging controller116D may be the same paging controller within the same access service network.

When the addresses are different, then anchor paging controller116B determines that mobile station112has switched to a new paging group, such as paging group110D in access service network104D. In this situation, a handover procedure may be performed without the knowledge of the mobile station112, to update its foreign to foreign agent114D of the access service network104D where mobile station112is now located. An example of a handover procedure for a mobile station operating in idle mode is described below.

In accordance with some embodiments, paging and data path establishment for mobile station112may occur quicker when mobile station112exits idle mode. As a result, the overall paging and network re-entry latency may be reduced. Furthermore, the network resources used to perform data path setup when mobile station112is to exit idle mode may be reduced and a shorter data path may be maintained between mobile station112and home agent118during idle mode.

FIG. 2illustrates an idle mode handover procedure in accordance with some embodiments of the present invention. Idle mode handover procedure200may be performed to maintain a current IP address of a mobile station, such as mobile station112(FIG. 1), that is in idle mode as the mobile station changes its location between paging groups110(FIG. 1) of different access service network104(FIG. 1). InFIG. 2, home agent118may correspond to home agent118(FIG. 1), relay paging controller (PC)116D may correspond to relay paging controller116D (FIG. 1), target foreign agent114D may correspond to foreign agent114D (FIG. 1), anchor paging controller116B may correspond to anchor paging controller116B (FIG. 1) and proxy mobile client120may correspond to proxy mobile client120(FIG. 1).

Referring toFIGS. 1 and 2, after mobile station112changes location between paging groups110, location update request message201may be received from relay paging controller116D at anchor paging controller116B. Anchor paging controller116B may determine whether mobile station112has switched access service networks104based on a network address of relay paging controller116D. When mobile station112has switched between access service networks104, handover request message203may be sent to proxy mobile client120of mobile station112to indicate a network address of target foreign agent114D for use when routing subsequent communications to mobile station112.

In some embodiments, the network address of relay paging controller116D may be received by anchor paging controller116B in location update request message201. In some embodiments, location update request message201may be sent from relay paging controller116D when mobile station112has changed its location from prior paging group110B to new paging group110D, although the scope of the invention is not limited in this respect.

In some embodiments, anchor paging controller116B may determine whether mobile station112has either switched paging groups110within current access service network104B or switched paging groups110to a new access service network, such as access service network104C or access service network104D, by comparing the network address of the relay paging controller received in location update request message201with a network address of a paging controller stored in a location register of anchor paging controller116B, although the scope of the invention is not limited in this respect.

In some embodiments, handover request message203may be sent if the network address of relay paging controller116D received in location update request message201is different from the network address of the paging controller stored in the location register of anchor paging controller116B. In some embodiments, handover request message203may be sent from anchor paging controller116B to proxy mobile client120of mobile station112. In some embodiments, handover request message203may include a network address of target foreign agent114D. In some embodiments, target foreign agent114D and relay paging controller116D may be associated with access service network104D, although the scope of the invention is not limited in this respect.

In some embodiments, anchor paging controller116B may refrain from sending handover request message203to proxy mobile client120if the network address of relay paging controller116D received in location update request message201matches the network address of the paging controller stored in the location register of anchor paging controller116B. In these embodiments, the matching addresses may indicate that mobile station112has changed paging groups110of paging controller116B of current access service network104B, although the scope of the invention is not limited in this respect.

In some embodiments, proxy mobile client120may send handover response message205in response to handover request message203. In these embodiments, handover response message205may indicate that the handover request message203was successfully received, although the scope of the invention is not limited in this respect. In some embodiments, proxy mobile client120may send registration request message207in response to receipt of handover request message203to target foreign agent114D. Registration request message207may instruct target foreign agent114D to register the mobile station112as being associated with home agent118and anchor paging controller116B, although the scope of the invention is not limited in this respect.

In some embodiments, in response to receiving registration request message207from proxy mobile client120, target foreign agent114D may send registration request message209to home agent118. In these embodiments, registration request message209may include an IP address of target foreign agent114D. Home agent118may store the IP address of target foreign agent114D for mobile station112for use in routing the subsequent communications to mobile station112, although the scope of the invention is not limited in this respect.

In some embodiments, home agent118may send registration response message211to target foreign agent114D in response to receipt of the registration request message209. Target foreign agent114D may send registration response message213to proxy mobile client120to indicate that home agent118has been updated with the IP address of target foreign agent114D, although the scope of the invention is not limited in this respect.

In some embodiments, proxy mobile client120may send handover confirmation message215to anchor paging controller116B to indicate that handover of mobile station112in idle mode has been successfully completed and that a prior foreign agent, such as foreign agent114B, is no longer a current foreign agent for mobile station112, although the scope of the invention is not limited in this respect.

In some embodiments, the network address of relay paging controller116D may be in either in a header (e.g., the source IP address) or a body of location update request message201, although the scope of the invention is not limited in this respect.

In some embodiments, mobile station112may be a mobile IP terminal associated with proxy mobile client120and proxy mobile client120may send mobile internet-protocol (MIP) registration request (RRQ) and MIP registration response (RRP) messages on behalf of mobile station112(i.e., for re-anchoring) when mobile station112changes paging groups110. In these embodiments, proxy mobile client120may perform at least some network operations (e.g., sending the MIP RRP and RRQ messages) on behalf of mobile station112, although the scope of the invention is not limited in this respect.

The use of proxy mobile client120does not involve a change in the point of attachment address when a mobile station moves allowing mobile station112to operate without an MIP stack. In these embodiments, mobile station112may be a mobile internet protocol IP terminal without capability to send the MIP RRP and RRQ messages when it changes location. In these embodiments, mobile station112may rely on proxy mobile client120to perform these network operations, although the scope of the invention is not limited in this respect.

In some embodiments, when mobile station112changes locations between paging groups110when in idle mode, mobile station112may send a ranging request (RNG-REQ) message to relay paging gateway116B through a base station of the new paging group110. Mobile station112may identify the new paging group110based on a paging group identifier (PG-ID) that may be broadcasted by the base stations of the new paging group110. In response to the ranging request message, relay paging gateway116D may send location update request message201to anchor paging controller116B as previously discussed. After registration response message213is sent to proxy mobile client120, a ranging response (RNG-RESP) message may be sent to mobile station112, although the scope of the invention is not limited in this respect. The ranging response message may indicate that the location update was successfully registered at the location register of paging controller116D.

In active mode, on the other hand, mobile station112ranging request messages are not sent by mobile station112when it crosses a paging group boundary because mobile station112may be tracked at the base-station level of granularity.

In some embodiments, proxy mobile client120for mobile station112may be located within first access service network104A, and anchor paging controller116B may be located within a second access service network104B. Relay paging controllers, such as relay paging controller110C or relay paging controller116D, may be located within either third or fourth access service network104C or104D respectively. In these embodiments, second access service network104B may be a prior access service network, and either a third access service network104C or fourth access service network104D may be a new access service network for mobile station112, although the scope of the invention is not limited in this respect.

In some embodiments, at least some of access service networks104may comprise broadband wireless access (BWA) networks, such as WiMax networks, that communicate with a plurality of mobile stations using a multiple-access technique, such as orthogonal frequency division multiple access (OFDMA). In some embodiments, mobile station112may be a broadband wireless access network mobile terminal, although the scope of the invention is not limited in this respect.

In some embodiments, data101destined for the mobile station112may be received at core service network102and may be routed to one of the access service networks104based on the IP address stored in home agent118for mobile station112. In some embodiments, at least some of data101may comprise voice-over IP data. In some embodiments, mobile station112may be operable in a push-to-talk mode, although the scope of the invention is not limited in this respect. In some embodiments, data101may comprise a paging or data-path establishment message directed to mobile station112, although the scope of the invention is not limited in this respect.

FIG. 3illustrates a block diagram of a paging controller in accordance with some embodiments of the present invention. Paging controller300may be suitable for use as any one of paging controllers116(FIG. 1). In some embodiments, paging controller300may be suitable for anchor paging controller116B (FIG. 1), although the scope of the invention is not limited in this respect. Paging controller300may include network interface circuitry302, processing circuitry304and location register306. Paging controller300may also include other functional elements not illustrated.

In accordance with some embodiments, network interface circuitry302may receive a location update request message, such as location update request message201(FIG. 2) from a relay paging controller, such as relay paging controller116D (FIG. 1) when a mobile station, such as mobile station112(FIG. 1) has changed paging groups110(FIG. 1). Location register306may store a network address of paging controller300. Processing circuitry304may determine whether mobile station112(FIG. 1) has switched access service networks104(FIG. 1) by comparing a network address of a relay paging controller received in location update request message201(FIG. 2) with a network address of paging controller300stored in location register306.

In some embodiments, when processing circuitry304determines that mobile station112(FIG. 1) has switched between access service networks104(FIG. 1), network interface circuitry302may send handover request message203(FIG. 2) to proxy mobile client120(FIG. 1) to indicate the address of the target foreign agent, such as foreign agent114D (FIG. 1), for use when routing subsequent communications to mobile station112(FIG. 1). In these embodiments, paging controller300may be operating as anchor paging controller116B.

In some embodiments, the handover request message203may be sent by network interface circuitry302if the network address of the relay paging controller received in location update request message201is different from the network address of the anchor paging controller stored in location register306. In some embodiments, network interface circuitry302may refrain from sending handover request message203(FIG. 2) to proxy mobile client120if the network address of the relay paging controller received in location update request message201(FIG. 2) matches the network address of the anchor paging controller stored in location register306.

In some embodiments, mobile station112(FIG. 1) may communicate orthogonal frequency division multiplexed (OFDM) communication signals over a multicarrier communication channel. The multicarrier communication channel may be within a predetermined frequency spectrum and may comprise a plurality of orthogonal subcarriers. In some embodiments, the multicarrier signals may be defined by closely spaced OFDM subcarriers. In some of these embodiments, mobile station112(FIG. 1) may communicate in accordance with a multiple access technique, such as orthogonal frequency division multiple access (OFDMA), although the scope of the invention is not limited in this respect. In some embodiments, mobile station112may be part of a wireless communication device that may communicate using spread-spectrum signals, although the scope of the invention is not limited in this respect.

In some embodiments, mobile station112(FIG. 1) may be a broadband wireless access (BWA) network communication station, such as a Worldwide Interoperability for Microwave Access (WiMax) communication station, although the scope of the invention is not limited in this respect. In some embodiments, mobile station112(FIG. 1) may be a portable wireless communication device, such as a personal digital assistant (PDA), a laptop or portable computer with wireless communication capability, a web tablet, a wireless telephone, a wireless headset, a pager, an instant messaging device, a digital camera, an access point, a television, a medical device (e.g., a heart rate monitor, a blood pressure monitor, etc.), or other device that may receive and/or transmit information wirelessly. In some BWA network embodiments, the frequency spectrum for the signals communicated by mobile station112(FIG. 1) may comprise frequencies between 2 and 11 gigahertz (GHz), although the scope of the invention is not limited in this respect.

In some embodiments, mobile station112(FIG. 1) may communicate in accordance with specific communication standards, such as the Institute of Electrical and Electronics Engineers (IEEE) standards including the IEEE 802.16-2004 and the IEEE 802.16(e) standards for wireless metropolitan area networks (WMANs) including variations and evolutions thereof, although the scope of the invention is not limited in this respect as they may also be suitable to transmit and/or receive communications in accordance with other techniques and standards. For more information with respect to the IEEE 802.16 standards, please refer to “IEEE Standards for Information Technology—Telecommunications and Information Exchange between Systems” Metropolitan Area Networks—Specific Requirements—Part 16: “Air Interface for Fixed Broadband Wireless Access Systems,” May 2005 and related amendments/versions.

Unless specifically stated otherwise, terms such as processing, computing, calculating, determining, displaying, or the like, may refer to an action and/or process of one or more processing or computing systems or similar devices that may manipulate and transform data represented as physical (e.g., electronic) quantities within a processing system's registers and memory into other data similarly represented as physical quantities within the processing system's registers or memories, or other such information storage, transmission or display devices. Furthermore, as used herein, a computing device includes one or more processing elements coupled with computer-readable memory that may be volatile or non-volatile memory or a combination thereof.

Some embodiments of the invention may be implemented in one or a combination of hardware, firmware and software. Some embodiments of the invention may also be implemented as instructions stored on a machine-readable medium, which may be read and executed by at least one processor to perform the operations described herein. A machine-readable medium may include any mechanism for storing or transmitting information in a form readable by a machine (e.g., a computer). For example, a machine-readable medium may include read-only memory (ROM), random-access memory (RAM), magnetic disk storage media, optical storage media, flash-memory devices, electrical, optical, acoustical or other form of propagated signals (e.g., carrier waves, infrared signals, digital signals, etc.), and others.