KR200391701Y1 - A wireless communication apparatus for implementing a media independent handover - Google Patents

Abstract

A wireless communication apparatus for implementing medium independent handover in a wireless communication system includes a station and an access point. The station includes a physical layer management entity, a media access control layer management entity, and a first medium independent handover layer. A first media independent handover layer is in communication with the physical layer management entity and the media access control layer management entity. The access point includes a second medium independent handover layer and a handover policy function. The second media independent handover layer is in communication with the first media independent handover layer and the handover policy function. The handover policy function determines whether the station executes handover.

Description

A WIRELESS COMMUNICATION APPARATUS FOR IMPLEMENTING A MEDIA INDEPENDENT HANDOVER}

The present invention generally relates to a wireless communication system, and more particularly to a wireless communication device for implementing media independent handover between different wireless network types.

A typical mobile system has two modes of operation, an idle mode and a connected mode. In idle mode, the station (STA) characteristic is: no user service (ie, no ongoing calls or transactions); Monitoring of paging channels; Available service request channels; 100% of the receiver is available for downlink measurements in a wireless environment; Background adjustment; And unscheduled access point (AP) and / or technology reselection. In the connected mode, the STA characteristics may include active user service (eg, call in progress); Handover possible; Limited receiver availability for measurements (because user service has priority); And fully coordinated and scheduled AP and / or technology handover.

Prior to entering idle mode (eg, upon power up), the STA must make a selection to determine the best AP and available technology for the requested user service. While in the idle mode, the STA constantly checks for adjacent APs and APs with different technologies. Upon determining a "better" AP, the STA will transition to the new AP (ie, perform a "reselection").

While in the connected mode, handover occurs on a transition from one AP to another that provides a "better" service, including the transition to an AP using a different technology. Ideally, handovers occur without noticeable interrupts to active user services.

One goal is to achieve seamless handover (ie, to allow STA mobility) between different wireless local area network (WLAN) types or between different wireless network types, such as between WLAN and cellular systems. . Current technology does not provide this type of handover.

1 is a diagram of an existing cellular mobility model 100, illustrating a central radio resource management (RRM) approach to mobility issues. The cellular STA 102 (eg, 2G mobile station or 3G user equipment) moves freely between the plurality of APs 104. The APs 104 may include a GSM based station and an FDD / CDMA Node Bs, but are not limited thereto. The APs 104 are connected to each other via the wireless network 106. The Handover Policy Function (HPF) 108 is used to handover the handover of the STA 102 between the APs 104 as the STA 102 moves around. The HPF 108 is centrally located (eg, in a 2G based station controller (BSC) or 3G radio network controller (RNC)) and connected to the network 110 (eg a switch or server).

The HPF 108 provides coordination as the STA 102 moves around different APs 104. The STA 102 sends a measurement to the HPF 108, which makes a final decision as to which handover and to which AP 104 the STA 102 will be placed.

In model 100, semi-static frequency allocation is made for each AP 104 and some radio planning is required. In idle mode, intra-technology (eg GSM vs GSM) and inter-technology (eg GSM vs FDD / WCDMA) AP selection / reselection decisions are performed by the STA 102. And is supported by system information (from network 110) broadcast by HPF 108. In connected mode, AP handover decisions are made at the HPF 108 and supported by measurements made at the STA 102 sent to the HPF 108 via L3 signaling.

2 is a diagram of an existing WLAN mobility model 200, illustrating a distributed RRM approach to the mobility problem. The 802 × STA 202 is free to move between the plurality of APs 204, including but not limited to 802.11a and 802.16 APs. The APs 204 communicate with the network 208 (eg, gateway or router) via the wireless network 206.

In model 200, dynamic frequency allocation is made for each AP 204 and no radio planning is required. The only handover type supported in the mobility model 200 is intra-tech (eg 802.11a vs. 802.11a) idle mode handover. Here, the AP selection / reselection decision is made autonomously at the STA 202. Other handover types (intra-tech idle mode and connected mode) are not supported in the mobile model 200.

In this distributed RRM approach, APs 204 can be deployed anywhere and they manage themselves dynamically. There is no central point where RRM is performed. Thus, no element in the architecture performs a handover.

3 is a diagram of an existing mobile system architecture for cellular and WLAN network types. GPRS (2G) STA 300 includes a physical layer 302, a data link layer 304, and a network layer 306. The data link layer 304 includes a medium access control (MAC) sublayer 310 and a radio link control (RLC) sublayer 312. Network layer 306 includes GSM radio resource (RR) manager 314, mobility management (MM) protocol manager 316, and internet protocol (IP) / convergence manager 318.

The 3GPP (3G) STA 320 includes a physical layer 322, a data link layer 324, and a network layer 326. The data link layer 324 includes a MAC sublayer 350 and a logical link (LLC) sublayer 352. Network layer 346 includes mobile IP manager 354 and IP / convergence manager 356.

The RR managers / controllers 314 and 334 manage the instantaneous radio link and process all of the information about the radio link. The MM protocol 316, 336, 354 handles network-wide issues such as registration and location updates as the STA moves around the system, ie external issues of the call itself.

Current WLAN systems provide only limited mobility capabilities. Intra-tech (e.g., 802.11 vs. 802.11) and inter-tech (e.g., 802.11 vs. 802.16) user transitions, unlike handover operation in a typical full mobility system (e.g. GSM), Supported using "break before make" which can be characterized as a selection operation. This problem limits the growth of WLAN technologies because this approach is not satisfactory for supporting real-time services such as voice and video streaming.

The present invention is a solution for implementing a full mobility solution for both intra-tech and inter-tech transition scenarios, and meets the requirements of both real-time and non-real-time. The present invention is a device-agnostic handover policy function that places little limitation on the physical implementation. The present invention supports WLAN to WLAN transition as well as WLAN to wired LAN transition and can be integrated into a typical mobile cellular system (eg GSM), allowing implementation of a full mobility WLAN / cellular solution.

A system for implementing media independent handover at one station of a wireless communication system includes a physical layer management entity, a media access control sublayer management entity, a management information base, and a handover policy function. The handover policy function may receive measurement and system information from a physical layer management entity, a media access control layer management entity, and a management information base. The handover policy function may autonomously determine whether to perform handover.

The system implements medium independent handover in a wireless communication system having a station and an access point. The station includes a physical layer management entity, a media access control layer management entity, and a media independent handover (MIH) layer. The MIH layer is in communication with the physical layer management entity and the media access control layer management entity. The access point includes a handover policy function that communicates with the MIH layer and determines whether the station should perform a handover.

One method for implementing media independent handover at a station of a wireless communication system begins by providing a handover policy function. System measurements and information are provided to the handover policy function from the station. The decision as to whether or not to perform handover is based on the system measurements and information.

One method for implementing medium independent handover in a wireless communication system begins by providing a medium independent handover (MIH) layer to a station and providing a handover policy function to an access point. Station measurements are sent from the station to the access point via the MIH layer. The handover policy function determines whether the station executes handover. Handover is controlled through the information sent from the MIH layer.

A station for implementing medium independent handover in a wireless communication system includes a physical layer management entity, a media access control layer management entity, a management information base, and a handover policy function. The handover policy function may receive measurement and system information from a physical layer management entity, a media access control layer management entity, and a management information base. The handover policy function may autonomously determine whether to perform handover.

An integrated circuit for implementing medium independent handover at one station of a wireless communication system includes a physical layer management entity, a media access control layer management entity, a management information base, and a handover policy function. The handover policy function may receive measurement and system information from a physical layer management entity, a media access control layer management entity, and a management information base. The handover policy function may autonomously determine whether to perform handover.

A system for implementing medium independent handover in a wireless communication system includes a station and an access point. The station includes a physical layer management entity, a media access control layer management entity, and a first media independent handover layer. A first media independent handover layer is in communication with the physical layer management entity and the media access control sublayer management entity. The access point includes a second medium independent handover layer and a handover policy function. The second media independent handover layer is in communication with the first media independent handover layer and the handover policy function. The handover policy function determines whether the station should execute a handover.

A more detailed understanding of the present invention is possible from the following description of the preferred embodiment given by way of example, in conjunction with the accompanying drawings.

Hereinafter, the term "station" (STA) includes, but is not limited to, a wireless transmit / receive unit, a user equipment, a fixed or mobile user unit, a pager, or any other device type operating in a wireless environment. The term "access point" (AP) hereinafter includes, but is not limited to, a base station, a Node B, a site controller, or any other type of interfacing device operating in a wireless environment.

4 shows a comparison with cellular network types as a diagram of a mobility architecture in a WLAN. GPRS STA 300 and 3GPP STA 320 are the same as the STAs described above in connection with FIG. The 802.xx STA 400 includes a physical layer 402, a data link layer 404, and a network layer 406. The data link layer 404 includes a MAC sublayer 410 and an LLC sublayer 412. The network layer 406 includes a media independent handover layer 414, a mobile IP manager 416, and an IP / convergence manager 418. The remainder of the discussion will focus on the Media Independent Handover (MIH) layer 414 and how it works in the mobility model. The MIH layer 414 performs similar functions as the GSM RR 314 and the 3G RRC 334.

5 is a diagram of a WLAN mobility model 500 in accordance with the present invention, showing two basic HPF options, distributed and centralized. These options relate to situations not described above by the mobility models, i.e., idle mode of inter-tech handover, and connected mode handover.

The 802.x STA 502 moves freely between the plurality of APs 504, including but not limited to 802.11a and 802.16 APs. These APs 504 communicate with a network 508 (eg, a gateway or router) via the wireless network 506.

Model 500 may implement distributed HPF 510 in STA 502 and central HPF 520 in network 508.

In a distributed HPF setup, the STA autonomously makes selection, reselection, and handover decisions. This includes idle mode, inter-tech select / reselect and both connected mode handover types.

In a central HPF setup, the HPF placed on the system side assists the selection and reselection processes and makes handover decisions supported by the information collected by the STA. This information is conveyed from the STA to the HPF via the signaling mechanism of the present invention (ie, MIH layer). This includes both idle mode, inter-tech select / reselect and connected mode handover types.

6 is a block diagram of a functional architecture for a STA 600 using distributed HPF of the present invention. The STA 600 includes a physical layer management entity (ME) 602 and a MAC sublayer (ME) 604. The HPF 606 communicates with a physical layer management entity (ME) 602 and a MAC sublayer (ME) 604. The local management information base 608 stores the information accessed by the HPF 606 upon making a handover decision. Physical sublayer (ME) 602 includes a physical layer convergence procedure (PLCP) sublayer 610 and a physical medium dependent (PMD) sublayer 612. MAC sublayer (ME) 604 includes MAC sublayer 614.

Reselection and handover decisions are made autonomously by the STA 600. The HPF 606 receives measurements from the MAC sublayer (ME) 604 and the physical sublayer (ME) 602 and other events (typically information used in handover decisions). The HPF 606 processes this information and makes an autonomous decision as to whether to perform a handover.

This is a limited handover solution, an extension of the reselection procedure, and is characterized in such cases as in a typical mobile system. Primarily due to the use of a "break then make" strategy, this is sufficient, but the next best thing. In addition to this strategy, when the STA finds that the radio link is deteriorating, the STA breaks the current link or fails the link before a new link is established. Resource availability to complete the handover is not guaranteed, and the new AP may lack resources to accommodate the handover and lead to dropped calls. The possibility of call truncation is an appropriate solution for non-real-time services, but an unacceptable solution for real-time services such as voice communications. Furthermore, this is a poorly scalable solution. For the same reason, that is, as more STAs are added to the system, performance will degrade.

7 is a diagram of a functional architecture for a STA 700 using a central HPF. The STA 700 includes a physical layer (ME) 702 and a MAC sublayer (ME) 704. The medium independent handover (MIH) layer 706 communicates with both the physical layer (ME) 702 and the MAC sublayer (ME) 704. The MIH layer 706 is in communication with the MIH layer 708 on the system side. The MIH layer 708 is in communication with the system HPF 710. Physical sublayer (ME) 702 includes a PLCP sublayer 712 and a PMD sublayer 714. MAC sublayer (ME) 704 includes MAC sublayer 716.

MIH layer 706 and system HPF 710 communicate via MIH layer 708. MIH layer 706 sends measurements to HPF 710 and HPF 710 sends system information to MIH layer 706. Reselection and handover decisions are coordinated between the MIH layer 706 and the HPF 710 based on this exchange of information. This use of both the MIH layer 706, the MIH layer 708, and the HPF 710 is similar to a cellular system type handover.

Reselection and handover decisions are coordinated by the HPF 710 and supported by system signaling and specific reporting received via the MIH layers 706, 708. This is a fast and optimal handover solution due to the centralized decision using a make then break strategy that ensures resource availability to complete the handover. This is a sufficient solution for non-real-time services, an acceptable but solution for real-time services, and easily scalable, thus providing a full mobility solution.

To support a full mobility solution, both a mobile protocol (eg MM Mobile IP and SIP, etc.) and a resource control protocol (eg RRC or MIH layer) are needed. The mobile protocol supports functions such as discovery, registration, tunneling, termination (or paging), handover at the network level (between two switches), and security. The resource control protocol supports functions such as system information, termination (or paging), cell selection / reselection, setup, release, measurement reporting, power control, and radio level (between two radios) handover. There is a need for handover support provided at both levels to support the full mobility solution.

On the network side, the MIH layer 708 and HPF 710 may be located in any centralized entity such as an AP, server, database, or router. In a preferred embodiment, the MIH layer 708 and HPF 710 are located in an AP or AP controller. MIH layer 708 and HPF 710 are separate logical entities. The MIH layer 708 acts as a state machine, collects the necessary information and passes it to the HPF 710. The HPF 710 makes a handover decision based on the received information.

Although the present invention has been described in terms of WLAN, the principles of the present embodiments are applicable to any type of wireless communication system. The central HPF architecture can be extended to support wireless-to-wired networking scenarios, such as handover policies when connecting wireless devices to wired systems. This example would be to use a handover to dock an laptop using an 802.11-capable laptop and take advantage of an Ethernet connection to a laptop docking station.

Although the elements shown in FIGS. 6 and 7 are shown as separate elements, these elements may be combined with one integrated circuit (IC), multiple ICs, abnormal components, or discrete elements, such as an application specific integrated circuit (ASCI). It may be implemented as a combination of IC (s). In some implementations, the functionality of the embodiments and the features of the subject innovation may appear as anomalous component (s) / IC (s) and may be partially or wholly disabled or inactive.

Although features and elements of the present invention are described in the preferred embodiments in specific combinations, each feature and element may be used alone or in various combinations without other features and elements of the present invention.

It satisfies the requirements of both real-time and non-real-time, and provides a solution for implementing a full mobility solution for both intra-tech and inter-tech transition scenarios. In addition, the present invention is a device-agnostic handover policy function that imposes almost no limitations on physical implementation, and supports WLAN to WLAN transitions as well as WLAN to wired LAN transitions. , GSM), allowing implementation of a full mobility WLAN / cellular solution.

1 is a diagram of an existing cellular mobility model.

2 is a diagram of an existing WLAN mobility model.

3 is a diagram of an existing mobile system architecture for cellular and WLAM network types.

4 illustrates a comparison with cellular network type as a diagram of a mobility architecture in a WLAN according to the present invention.

5 is a diagram of a WLAN mobility model according to the present invention.

6 is a diagram illustrating a configuration of an STA architecture for implementing the distributed handover policy function of the present invention.

7 is a diagram illustrating a configuration of an STA architecture for implementing the central handover policy function of the present invention.

Claims (4)

An integrated circuit for implementing medium independent handover at a station of a wireless communication system, Physical layer management entity; A media access control sublayer management entity; Management information base; And A handover policy function, wherein the handover policy function may receive measurement and system information from the physical layer management entity, the media access control sublayer management entity, and the management information base; And the function is capable of autonomously determining whether or not to execute a handover. A wireless communication apparatus for implementing medium independent handover in a wireless communication system, A station including a physical layer management entity, a medium access control layer management entity, and a first medium independent handover layer in communication with the physical layer management entity and the medium access control layer management entity; A second medium independent handover layer in communication with the first medium independent handover layer, and a handover policy function in communication with the second medium independent handover layer and determining whether the station performs a handover. Access point Wireless communication device comprising a. 3. The method of claim 2, wherein the first medium independent handover layer sends a station measurement to the second medium independent handover layer, and the handover policy function uses the station measurement in making a handover decision. , Wireless communication device. 3. The wireless communication of claim 2, wherein the second medium independent handover layer sends system information to the first medium independent handover layer, wherein the system information assists the station in executing handover. Device.