Wireless communication access point configured to implement handoff in a wireless local area network

A wireless communication access point configured in a wireless local area network to implement handover

This creation is related to a wireless local area network (WLANs), and related to methods and devices for facilitating the "roaming" of a wireless transmit/receive unit (WTRU) by converting communication via one communication station to another. In particular, the advantageous implementation of this creation is through wireless transmit/receive units (WTRUs) configured to operate in wireless local area networks (WLANs) operating in accordance with the IEEE802 standard, and the wireless transmit/receive units (WTRUs) can conduct and Wireless communication with access points (APs) of wireless local area networks (WLANs), and continue when the wireless link of one access point (AP) is switched to the wireless link with another access point (AP) One wireless communication.

Wireless communication systems are widely known in the art. Generally speaking, such systems include communication stations that transmit and receive wireless signals between each other. Depending on different system types, communication stations are typically one of the following two types of wireless transmit/receive units (WTRUs): one type is a base station, and the other type is a subscriber unit, which can be mobile.

The term "base station" used here includes a base station, an access point, Node B, a base station controller, or other interface devices in a wireless environment or a wireless transmit/receive unit (WTRU), but is not Limited to this. The term "base station" used here provides other wireless transmit/receive units (WTRUs) with wireless access to a network that incorporates an access point (AP).

The term "wireless transmit/receive unit (WTRU)" used here includes a user equipment, mobile station, fixed or mobile subscriber unit, or other types of devices that can operate in a wireless environment, but it is not Limited to this. Such wireless transmitting/receiving units (WTRU) include personal communication devices, such as telephones, video phones, and Internet phones with network connections. In addition, the network incorporates an access point (AP). The wireless transmit/receive unit (WTRU) includes portable personal computing devices, such as personal digital assistants (PDAs) and notebook computers with similar network possibilities and wireless data devices. A wireless transmit/receive unit (WTRU) that is portable or can be changed in other ways is classified as a mobile unit.

Typically, a base station network is provided like multiple appropriately configured base stations, where each base station can conduct simultaneous wireless communication with appropriately configured wireless transmit/receive units (WTRUs). Certain wireless transmit/receive units (WTRUs) can also be configured to directly conduct magnetic wire communication between each other. In other words, there is no need to rely on a network via a base station. This is usually called point-to-point wireless communication. Where a wireless transmit/receive unit (WTRU) is configured to directly communicate with other wireless transmit/receive units (WTRUs), its own configuration and function may also be the same as a base station. Wireless transmit/receive units (WTRUs) can be set up to be used in multiple networks with both network and peer-to-peer communication possibilities.

A type of wireless system called "a wireless local area network (WLAN)", which can be set up to conduct wireless communication with wireless transmit/receive units (WTRUs) with wireless local area network (WLAN) data devices. Conduct point-to-point communication with similarly configured wireless transmit/receive units (WTRUs). Currently, wireless local area network (WLAN) modems are integrated into many traditional communication and computing devices through manufacturing. For example, cellular mobile phones, personal digital assistants, and desktop computers have built-in one or more wireless local area network (WLAN) data machines.

Common wireless local area network (WLAN) environments with one or more wireless local area network (WLAN) base stations, including those based on one or more standard IEEE 802 family builders, generally called access points (APs) . Access to these networks usually requires user authentication procedures. Recently, in the field of wireless local area network (WLAN) technology, the protocol of such a system has been standardized. Such a frame of agreement is represented by the standard IEEE 802 family.

The Basic Service Set (BSS) is a basic building block of IEEE 802.1.1 Wireless Local Area Network (WLAN), which includes wireless transmit/receive units (WTRU) which are also called base stations (STAs). A set of working base stations (STAs) that can talk to each other can form a basic service set (BSS). Through an artificial component called Distributed System (DS), multiple basic service sets (BSSs) are interconnected to form an extended service set (ESS). An access point (AP) is a wireless transmit/receive unit (WTRU) that provides access to a distributed system (DS) by providing a distributed system (DS) service, and it usually passes through multiple working base stations (STAs) to allow Simultaneous access to the distributed system (DS).

A network of wireless transmit/receive units (WTRUs) operating point-to-point communication in an IEEE802.1.1 environment is typically called an "ad hoc" mode, which is also called an "Independent Basic Service Set (IBSS)" . In an independent basic service set (IBSS), two or more wireless transmit/receive units (WTRUs) establish communication between them without the need for peer-to-peer network components. However, an access point (AP) can be set up to use the ad hoc protocol and play the role of a wireless transmit/receive unit (WTRU) in peer-to-peer communication. In this case, an access point (AP) can act as a bridge or router to another network or sub-Internet.

Activate a wireless transmit/receive unit (WTRU) of an ad hoc network to select the operating parameters of the ad hoc network, such as: service identification code (SSID), signal arrival, and beacon time, and they are in the communication frame Transmit this information, for example in a beacon frame. When other wireless transmit/receive units (WTRUs) join the ad hoc network, they detect and use the operating parameters of the ad hoc network.

Where a network infrastructure is used and wireless communication is controlled through access points (APs), its parameters, such as service identification code (SSID), are usually clearly specified by a network controller accompanying the access point (AP) . This access point (AP) periodically broadcasts for the wireless transmit/receive unit (WTRU) to recognize the access point (AP) and try to establish communication with them.

The service identification code (SSID) in an IEEE 802-based system can be a 32-character special identification code transmitted in the header of the packet received in a wireless local area network (WLAN). Next, when a wireless transmit/receive unit (WTRU) tries to connect to a basic service set (BSS) or an independent basic service set (IBSS), this service identification code (SSID) is used as a password. The service identification number (SSID) distinguishes a wireless transmit/receive unit (WTRU) from others, so all base stations and all other devices connected to or attempting to connect to a specific wireless local area network (WLAN) The same service identification number (SSID) is usually used. Generally, a device will not be allowed to join a basic service set (BSS) unless the device provides the correct service identification code (SSID).

In an access point-based wireless local area network (WLAN), when located in the geographic service range of a specific access point (AP), a mobile wireless transmit/receive unit (WTRU) and the specific access point ( AP) Wireless communication. The wireless transmit/receive unit (WTRU) is connected to the access point (AP), through which it conducts wireless communication. Sometimes for a wireless transmit/receive unit (WTRU), it is necessary or desirable to change the access point (AP) connected to it. For example, a wireless transmit/receive unit (WTRU) may experience a weak signal condition because it moves beyond the service geographic area of the access point (AP) to which it is connected. The need to connect to other access points (AP) can also be caused by the increase in congestion in the basic service set (BSS) served by the access point (AP). Reconnection is usually called roaming, especially when the wireless transmit/receive unit (WTRU) has an assigned "home" access point (AP) (or network access point (APs)), when the wireless transmit/receive unit (WTRU) communicate through a different access point (AP) (or different network access points (APs)), and then "roam".

In wireless local area networks (WLANs) in accordance with the current IEEE802 standard, the start of a wireless transmit/receive unit (WTRU) reconnecting to a new access point (AP) is entirely through the wireless transmit/receive unit (WTRU). ). In order to accomplish this, a wireless transmit/receive unit (WTRU) must first identify the access points (APs) in its vicinity that may provide network services to the wireless transmit/receive unit (WTRU). This is usually achieved through a scanning process, which can be active or passive.

During active scanning, the wireless transmit/receive unit (WTRU) transmits probe requests on one or more frequency channels that the wireless transmit/receive unit (WTRU) is set to communicate with. The wireless transmit/receive unit (WTRU) selects a new access point (AP) from the access points (APs) requested by the receiving probe. During passive scanning, the wireless transmit/receive unit (WTRU) stops on its available channels in an attempt to receive beacon packets transmitted by access points (APs), which serve the next The location of the wireless transmit/receive unit (WTRU). Then the wireless transmit/receive unit (WTRU) selects a new access point (AP) from the access points (APs) to which it receives the beacon packet. Under the condition that an ongoing communication can be maintained, either active or passive scanning may take a considerable amount of time, especially when the wireless transmit/receive unit (WTRU) is moving.

The author admits that sometimes it is desirable to initiate a re-association of a WTRU with an AP. For example, Aps (or some other node controlling the behavior of a WTRU) may determine a current "load" based on the amount of wireless communication data collected based on the number of WTRUs associated with the AP and/or the form of conducted communication. condition. In addition, it is also possible to place a WTRU in a location served by several neighboring APs, where each of the Aps may use channels different from those in which the WTRU may communicate. Among them, the collected data traffic is relatively high for an AP (heavy load), and the data traffic of one or more neighboring Aps is relatively low (light load). One or more WTRUs that the load AP first associates are re-associated with a nearby lightly loaded AP.

In WLANs compliant with the current 802.11 standard, these re-associations will only occur when those WTRUs associated with heavily loaded APs have a highly developed algorithm that allows them to automatically decide that they want to re-associate with other valid APs. , And its basis is the estimated value of the data stream on the channel. It is difficult to determine that all WTRUs have this kind of algorithm, and the design and implementation of this kind of algorithm is very difficult. Even if all WTRUs in a particular geographic area have this kind of algorithm, it is difficult to guarantee that WTRUs will not re-associate with other Aps in a chaotic manner, which may cause forward or backward operations between the same Aps. Reverse multiple re-association.

In order to avoid these problems, the creators have discovered potential solutions. For example, a heavily loaded AP can be strongly separated from some selected WTRUs in the hope that these WTRUs can later find other APs with which they can re-associate. It is also possible to indirectly induce separation by reducing the transmit power level of a specific key packet transmitted, such as the transmit power level of a beacon or probe response packet. The problem with these separation technologies is that they may cause some WTRU users to be unable to accept service splitting, for example, users of real-time audio or video services. These splits are caused by the WTRU taking a certain amount of time after the separation to be able to scan for a new AP. Looking at all the issues, the creators believe that a device and method that allows an AP to initiate a WTRU from one AP to another AP without compromising performance will be expected.

This case provides a communication method, system, and components, which include a hand-shaking procedure for allowing the WTRU to communicate with a network base station through a first communication parameter set, and the hand-shaking procedure is through a second communication parameter set. Group and communicate with another network base station by handoff. Preferably, the access point (AP) of the original wireless local area network (WLAN) requests or instructs the WTRU to handover a target access point AP. In addition, the target access point AP of the WTRU may request or command the WTRU to handover the target access point AP from the original access point AP with which the WTRU communicates.

Preferably, in an IEEE 802-type WLAN specification, this document provides four specific solutions for individual or combined implementation of a specific WLAN, that is: 1. An original access point AP requests a WTRU to check a specific WLAN. The target access point AP performs a handover, and the WTRU then decides whether to handover and whether to communicate with the original access point AP. In the case that the WTRU decides to perform the handover, the WTRU then reconfigures its channel, BSSID, etc., for the target access point AP, and sends a confirmation message indicating that it has completed the re-association to the target storage device. Take some AP.

2. An original access point AP orders a WTRU to handover a target access point AP, the WTRU then reconfigures its channel, BSSID, etc. for the target access point AP, and sends an indication that it has been completed The re-association confirmation message is given to the target access point AP.

3. A target access point AP orders a WTRU to handover the target access point AP, the WTRU then informs an original access point AP with which it has immediate handover communication, and gives the target access point AP Reconfigure its channel, BSSID, etc., and send a confirmation message indicating that it has completed re-association to the target access point AP.

4. A target access point AP requests a WTRU to handover the target access point AP, and the WTRU decides whether to handover and whether to communicate with the target access point AP. In the case that the WTRU decides to perform handover in advance, the WTRU notifies an original access point AP with which it has immediate handover communication, and reconfigures its channel, BSSID, etc., for the target access point AP, and Send a confirmation message indicating that it has completed re-association to the target access point AP.

More detailed understanding of this case can be obtained from the following description of the preferred embodiment through examples, and can be understood in conjunction with accompanying drawings, in which similar components will be described with similar numbers.

The terms used in the following text: access point (AP), original access point AP, target access point AP, and wireless transmit/receive unit (WTRU) have the same meaning as described in the foregoing content. This creation proposes a wireless radio access network, the wireless radio access network has multiple network APs, and through those network APs, wireless network services can be provided to one or more WTRUs. This case is particularly useful when it is used in conjunction with a mobile WTRU and the mobile WTRUs pass through the geographic area covered by each service provided by individual Aps. These WTRUs may be integrated or configured wireless WLAN devices, such as 802.11(a), 802.11(b), 802.11(g) or 802.11(n) compliant devices, to facilitate communication. However, this case is suitable for use in various wireless systems.

The term guided reassociation request (DRRq) refers to a signal that is directed to a WTRU request that requires the WTRU to reassemble itself to communicate with a different network station, such as a target access point AP. . In a WLAN IEEE 802.11 background, DRRq may be sent by the original AP or the target AP.

The information contained in DRRq preferably includes data sufficient to identify a target AP and sufficient to enable the WTRU to communicate with the target AP. The information preferably includes the channel of the target access point AP, the identification of the target access point AP (MAC address, IP address, etc.), the target BSSID, the capacity of the target access point AP, and so on. The DRRq preferably also includes time information about when the handoffs are sorted. A flag or a special value in a time field can be used to indicate that the handover takes place immediately. DRRq also includes specific signal information, such as which signal steps need to be exchanged. For example, DRRq also indicates whether the target AP intends to receive a guided reassociation confirmation, or whether the original AP wants to receive a guided reassociation indication.

In a case where a DRRq is sent by a target AP, the target AP preferably uses the same channel to send DRRq to the WTRU and the original AP that is communicating with the WTRU, and the The WTRU is using this channel. In a preferred embodiment, DRRq is used as a unicast frame. More precisely, it can be a control frame, a management frame, or the layout of a data frame. In another embodiment, signal delivery can be implemented by using multicast or broadcast messages.

The term guided re-association response (DRRsp) refers to a signal from a WTRU that directly leads to the network station that sent the DRRq, where the DRRq is even sent to the WTRU. DRRsp preferably indicates whether the WTRU accepts or rejects the request to re-equip itself to communicate with a different network station, such as a target access point AP.

The term guided re-association command (DRCm) refers to a signal from a network station that directly leads to a WTRU, instructing the WTRU to re-equip itself to access a different network station, such as a target. Tap the AP to communicate. In a WLAN IEEE 802.11 background, DRCm may be sent by the original AP or the target AP. The WTRU is expected to follow DRCm and therefore does not need to issue a DRRsp to the network station that issued the DRCm. DRCm preferably contains the same target access point AP information as the aforementioned DRRq.

In the case where the target access point AP sends the DRCm, the target access point AP preferably uses the same channel to send the DRCm to the WTRU and the original access point AP that is communicating with the WTRU, and the WTRU is The channel is being used. In a preferred embodiment, DRCm is used as a unicast frame. More precisely, it is a control frame, manages the frame or is regarded as the layout of a data frame. In another embodiment, signal delivery can be implemented by using multicast or broadcast messages.

The term guided reassociation confirmation (DRCf) refers to a signal sent to the network after a WTRU has re-equipped itself to communicate with a network station, such as a target access point AP. Road station, such as a target access point AP. The DRCf confirms that the WTRU has re-equipped itself. The DRCf is used to avoid sending an unwanted communication definition table to the WTRU before the WTRU has successfully re-associated to the target access point AP, where a target access point AP of the unwanted communication definition table has been Start sending packets. This may result in the target AP not needing to transmit or re-transmit frames to a WTRU that expects to re-equip itself to the target AP but does not do so. In this case, because the back window related to those multiple retransmissions is increased exponentially, the number of frames buffered in the target access point AP may be very large, and it may lead to the efficiency of the wireless media. decline. In addition, if a target AP cannot receive a DRFc indicating that re-association has been successfully performed in a desired period of time, the target AP will eventually release any radio resources that may be reversed for the WTRU. .

The information contained in the DRCf preferably includes data sufficient to identify an original access point AP, the WTRU communicating with the original access point AP, the target access point AP, and the WTRU. In an IEEE802.11 background, the DRCf preferably includes an indication of a communication channel, an identifier (MAC address, IP address, etc.), the target BSSIDs used, and the capacity of the target and the original access point AP. DRCf may also contain time information about when the handover occurred. In a preferred embodiment, DRCf is used as a unicast frame. More precisely, it can be a control frame, a management frame, or the layout of a data frame. In another embodiment, signal delivery can be implemented by using multicast or broadcast messages.

This guided re-association indication (DRI) term means that the signal from a WTRU to a network base station has communicated with the WTRU (for example, an original access point AP), and this is in the WTRU It has been requested or ordered to reconfigure itself by another base station (such as a target access point AP) and the WTRU is doing so afterwards. The DRI is preferably used to indicate to an original AP so that the WTRU will reconfigure itself to a target AP. The DRI allows an original AP to stop sending packets to the WTRU (which will lead to inefficient use of the wireless medium), and to forward any buffered packets to the target AP. The DRI also allows an original access point AP to release all the radio resources reserved for the WTRU.

The information including the DRI in the IEEE 802.11 specification is the channel with the target access point AP, the identifier of the access point AP (MAC address, IP address, etc.), the target BSSID, the Target access point AP performance and so on. The DRI also includes timing information about when the handover is scheduled, and a flag or specific value in the timing field can be used to indicate that the handover means immediate. In a preferred embodiment, the DRI can be implemented as a unicast frame, more particularly as a control frame, a management frame, or as a payload of a data frame. In another embodiment, this signal can also be implemented using multicast or broadcast messages.

Please refer to Figure 1, which illustrates a WLAN in which the WTRU transmits wireless communication through a network base station, in this example an access point AP. The access point AP is connected to a DS, and the access point AP is shown to communicate with five WTRUs. Such a configuration may also be referred to as a basic service set (BSS) in the WLAN specification herein. Generally speaking, the system supports WTRUs with different data rates. In some examples, APs are configured to support multiple types of WTRUs, such as WTRUs that comply with 802.11(b) and 802.11(g).

Please refer to Fig. 2, which reveals that a WLAN has two APs representing the original AP and the target AP. Its WTRU appears to transmit wireless communication through the original access point AP, and the WTRU is configured in an area that provides both the original access point AP and the target access point AP. Therefore, the WTRU may The communication from the original access point AP to the target access point AP is "handed over".

When, for example, the WTRU starts to move further away from the original access point AP and move to the target access point AP, according to the conventional IEEE 802.11 WLAN specifications, the WTRU will The handover operation from the access point AP to the target access point AP is initiated. For such an initial exchange of the WTRU, the handover operation must be completed before the WTRU leaves the range of the original access point AP, so as to avoid interruption of the uninterrupted wireless communication transmitted by the WTRU.

According to the content of this case, the WTRU is used to provide further functions to allow the access point AP to also decide whether or when a handover should occur. This function allows the WTRU to cope with the congestion problem caused by the individual cell of each access point AP or different traffic in the service area. In this way, the load balancing and congestion control algorithms can be activated without jeopardizing user experience to effectively improve the health of the network, and more effective international roaming can also be activated. According to the implementation of the content of this case, the original access point AP and/or the target access point AP may request and/or command the WTRU to handover the target access point AP. Preferably, in the IEEE Type 802 WLAN specification, this article provides four specific solutions to implement a specific WLAN individually or in combination.

Please refer to Figure 3, the first solution is to describe that the original access point AP requests the WTRU to handover the target access point AP. The WTRU then decides whether to handover and whether to communicate its decision to the original access point AP. In the case that the WTRU decides to perform the handover, the WTRU then reconfigures its channel, BSSID, etc., for the target access point AP, and sends a confirmation message indicating that it has completed the re-association to the target storage device. Take some AP. Such a reconfiguration procedure itself is preferably substantially the same as the steps of the conventional WTRU initialization and handover, but one of the access points AP preferably provides reconfiguration related to the target access point AP in DRRq The information of the message.

As in the first step, the original AP decides that the WTRU should be redirected to a target AP. Such a decision may be based on the type and degree of communication traffic guided by the original access point AP compared to the target access point AP. The original access point AP then transmits a DRRq to the WTRU to request the WTRU to hand over to the target access point AP. The WTRU decides whether it receives the redirect request, and transmits its decision to the original access point AP through a DRRsp. Such selection allows, for example, the WTRU to determine whether a desired quality of service can be obtained from the target AP. In the case that the WTRU receives a handover request with the target access point AP, the WTRU reconfigures itself to the target access point AP, and a DRCf is stored for the target access point AP. Take the AP to confirm that the handover has been carried out.

Please refer to FIG. 4, a second solution is illustrated by the diagram, in which the original access point AP commands a WTRU to handover with a target access point AP. According to such instructions, the WTRU reconfigures the channel and BSSID provided to the target access point AP, and transmits a confirmation message to the target access point AP to indicate that it has completed re-association .

In this solution, when the original access point AP decides that the WTRU should be redirected to a target access point AP, the original access point AP transmits a DRCm to the WTRU, so The DRCm is used to order the handover with the access point AP. The WTRU reconfigures itself to the target access point AP, and transmits a DRCf to the target access point AP. Where DRCm is used, it is better for the WLAN to make a judgment before issuing such a command to ensure the quality of service obtained from the target access point AP. Such determination may be based on the geographic location information of the WTRU, and the geographic location information may be obtained from the WTRU through signal transmission, or the WLAN may be based on the signal received from the WTRU Or measurement report to calculate.

Referring to FIG. 5, a third solution is illustrated by the drawing, in which the target access point AP commands a WTRU to handover with the target access point AP. The WTRU then informs an original access point AP that it is facing an approaching handover, reconfigures its signal, BSSID, etc. for the target access point AP, and transmits a confirmation message to the target Access point AP, where the confirmation message indicates that it has completed re-association.

In this solution, the target AP preferably decides that the WTRU should be redirected to the target AP. The target access point AP may, for example, be reconfigured to be based on an interrupt signal from the WTRU redirected to the original access point AP or based on the target access point AP before issuing an instruction. It is determined from the measurement report obtained from the target access point AP by relaying the signal of the access point AP that a desired service quality can be provided from the target access point AP. If the WTRU uses a directional antenna as its signal transmission device to the original access point AP, the interrupt signal from the WTRU may be ineffective. The target access point AP transmits a DRCm to the WTRU to order the WTRU to handover with the target access point AP. Preferably, the target access point AP uses the channel currently used by the WTRU to communicate with the original access point AP to transmit the DRCm. After transmitting the DRCm, other communications between the target AP and the WTRU are better to use the operating channel of the subsequent target AP. The WTRU transmits a DRI communication to the original access point AP, and the DRI communication will reconfigure the target access point AP. The WTRU then reconfigures itself to the target access point AP, and then transmits a DRCf to the target access point AP to confirm that it has completed the handover.

Referring to FIG. 6, a fourth solution is illustrated by the drawing, in which the target access point AP requests the WTRU to handover with the target access point AP. The WTRU decides whether to handover, and transfers the decision to the target AP. In the case that the WTRU decides to perform a handover further, the WTRU informs the original access point AP that it is about to face an approaching handover communication, and configures itself to provide to the target access point AP. The used channel, BSSID, etc., and a confirmation message is sent to the target AP, and the confirmation message indicates that it has completed re-association.

In this fourth solution, the target access point AP decides that the WTRU should be redirected to the target access point AP. Preferably, the target access point AP uses the frequency channels used by these WTRUs to communicate with the original access point AP to transmit a DRRq to the WTRU to request the WTRU and the The target access point AP is handed over. The target access point AP then communicates with the WTRU on the preferred operating channel of the target access point AP. The WTRU in question decides whether it receives a redirection request. It communicates its decision to the target access point AP through a DRRsp, and preferably it communicates through the operation signal of the target access point AP. In the case that the WTRU accepts a communication request with the target access point AP, the WTRU transmits a DRI to the original access point AP to communicate its decision. Preferably, it is used to It is transmitted through the communication channel with the original access point AP. The WTRU then reconfigures itself to the target access point AP and transmits a DRCf to the target access point AP to confirm that it has completed the handover.

An alternative embodiment of the fourth solution is to integrate the DRRsp and the DRCf (or use DRRsp to spoof the DRCf), wherein the WTRU decides to receive the AP from the target access point 'S redirect request. This alternative embodiment eliminates the need for the WTRU to switch communication parameters multiple times during the handover. This alternative embodiment also implies that both the original access point AP or the target access point AP use the same channel, or after the DRRq is transmitted, the target access point AP is still Maintain the original AP channel until the DRCf is received.

The described method of using the access point AP to drive the handover process to determine which access point AP is appropriate or the desired target access point AP candidate may include, for example, the The WTRU reports a series of AP candidate lists, relays AP signalling, centralized decision making in the central controller, or any other appropriate method. In terms of implementation, a preferred WTRU includes a transmitter and receiver and a processor configured to perform wireless communication handover, where the wireless communication handover refers to the use of a wireless communication switch based on the initial information of the access point AP. A first access point (AP) of the first set of communication parameters to a second access point that uses a second set of communication parameters. The transmitter and receiver are preferably configured to use the first set of communication parameters to receive a re-association message. The first set of communication parameters identify the second access point AP and the The second set of communication parameters. The processor is operatively associated with the transmitter and receiver, and it is preferably configured to selectively reconfigure the transmitter and receiver in response to the received re-association message through all The second set of communication parameters are communicated, so that the transmitter and receiver can send a reconfiguration confirmation message to the second access point AP that uses the second set of communication parameters. Preferably, the WTRU is configured with an IEEE The 802.11 system operates so that the transmitter and receiver can be configured to communicate in a predetermined frame format. The re-association message from the first access point AP is then preferably received in a guided re-association command, and the reconfiguration confirmation message of the second access point AP is transmitted to the guided re-association message Re-association confirmation dialog box.

In the WTRU, the processor may be configured to direct the transceiver to transmit a re-association instruction message to the first access point AP, and the re-association instruction message and processing A received re-association message, wherein the received re-association message refers to the second access before the reconfiguration of the transmitter and receiver to communicate through the second set of communication parameters A re-association command transmitted by a point AP; wherein the WTRU is configured to use a predetermined frame format, such as a system conforming to IEEE 802.11, and the processor is preferably configured to guide the The transmitter-receiver receives a re-association message in a guided re-association instruction frame from the second access point AP, and sends the re-association instruction to the first access point AP. A guide re-association instruction frame, and a guide re-association confirmation frame transmits the reconfiguration confirmation message.

The WTRU processor may be configured to make a decision regarding the reconfiguration of communication through the second set of communication parameters in response to a received re-association request. In this case, the processor is preferably configured to direct the transceiver to transmit the access point AP that determines the decision, wherein the re-association request is a guided Being received in the re-association response message has caused the processor to guide the transmitter and receiver to configure to communicate through the second set of communication parameters, wherein the decision is processed together with the re-association. In the WTRU configured to use a predetermined frame format in accordance with the IEEE 802.11 system, the processor is preferably configured to direct the transmitter and receiver to a system from the first The access point APs guided re-association request (DRRq) frame receives a re-association request to transmit information related to the re-association in a guided re-association response (DRRsp) frame using the first communication parameter Determine, and transmit the reconfiguration confirmation in a guided reassociation confirmation (DRCf) frame using the second set of communication parameters.

The WTRU processor may be further configured to direct the transceiver to use the second set of communication parameters to transmit a guided reconfiguration response related to processing an association request received from a second access point AP message. The processor may also be configured to direct the transmitter and receiver to send a re-association instruction using the first set of communication parameters to the first access point AP, wherein the re-association instruction The association instruction is related to processing an association request received from the second access point AP, wherein the decision is processed together with the re-association. In the WTRU configured to use a predetermined frame format in accordance with the IEEE 802.11 system, the processor is preferably configured to direct the transmitter and receiver to a guided re-association request (DRRq) To receive a re-association request in the frame, transmit the re-association instruction from a guided re-association indication (DRI) frame, and transmit the re-configuration in a re-directed re-association confirmation (DRCf) frame confirm. The WTRU processor may then be configured to direct the transmitter and receiver to transmit a decision related to reassociation in a guided reassociation response (DEEsp) frame located in front of the DRI frame.

The preferred implementation on the network side is to provide WLAN APs and the WTRUs through specific APs, where each WLAN APs includes a transceiver and a processor that are selectively used to support a wireless communication handover. Preferably, the AP transceiver uses a set of defined communication parameters to provide wireless network access for wireless transmit/receive units (WTRUs). Preferably, the AP processor uses a pre-handover parameter set to make a decision regarding a wireless communication handover handled by a WTRU, the handover is from the access point AP or transmitted to the access point. Click AP. The processor uses the pre-handover communication parameter group to guide the transceiver to transmit a re-association message that can identify a handover AP and a post-handover communication parameter group when a handover decision is generated. Preferably, the transceiver of the access point AP is used to receive a reconfiguration confirmation from a WTRU, where the WTRU has received a reassociation message and handed over, and where the access point AP is received by the WTRU The access point AP identified by the handover in the re-association message.

In order to implement the above second solution, preferably, the access point AP is used to operate in an IEEE 802.11 compliant system, in which the transceiver uses a preset frame format to transmit the re-association message to guide the re-association Command the WTRUs in the frame and receive the reconfiguration confirmation from the WTRUs in the guided reassociation confirmation frame.

The transceiver may receive a re-association instruction message from a WTRU, where the WTRU processes a wireless communication through the access point AP, and the re-association instruction message indicates a communication handover through another access point AP , To implement the third program. Preferably, the processor is used to release resources allocated for communication regarding receiving the re-association instruction message. In addition, in order to implement the third solution, preferably, the access point AP is operated in an IEEE 802.11 system, wherein the transceiver communicates in a preset frame format, and the processor is used to guide the transceiver The device transmits a re-association message in the guided re-association instruction frame, and receives a re-association instruction in the guided re-association instruction frame, and also receives a reconfiguration confirmation in the guided re-association confirmation frame.

In order to implement the first solution, preferably, the AP processor guides the transceiver to transmit a re-association message in the form of receiving a re-association request when a handover decision is generated, and the transceiver is used In order to receive a guided re-association response message from WTRUs that have received a re-association request from the AP, the guided re-association response message responds to a responding WTRU decision regarding re-association. Preferably, the access point AP is operated in an IEEE 802.11 compliant system, wherein the transceiver uses a default frame format, and the processor is used to direct the transceiver to initiate a re-association request (DRRq) ) The re-association request is transmitted in the frame, and the decision about re-association is received in the guided re-association response (DRRsp) frame, and the reconfiguration confirmation is also received in the guided re-association confirmation (DRCf) frame.

For the fourth solution, preferably, the access point AP transceiver uses the post-handover communication parameter set to receive a guide reconfiguration response message, wherein the access point AP processor has used a pre-handover communication parameter set To guide the transceiver to transmit a re-association message to a WTRU, the WTRU recognizes the handover access point AP as the access point AP itself, and recognizes the post-handover communication parameter set as the first communication parameter set. The access point AP transceiver can also receive a re-association instruction message from a WTRU, where the WTRU handles a wireless communication through the access point AP, and the re-association instruction message is sent through another access point AP. Instructs a communication handover, and the processor is used to release the resources allocated to the communication about receiving the re-association instruction message.

For the first and fourth schemes, preferably, the access point AP operates in a system compliant with IEEE 802.11, in which the transceiver uses a default frame format. Then preferably, the processor is used to guide the transceiver to transmit a re-association request in a guided re-association request (DRRq) frame, and receive a re-association instruction in a guided re-association instruction (DRI) frame, and also in The guided reassociation confirmation (DRCf) frame receives the reconfiguration confirmation, and the guided reassociation response (DRRsp) frame receives the decision about reassociation.

Even though the features and elements of this case have been recorded in the preferred embodiment by specific combinations, each feature or element can be used alone (without other features and elements of the preferred embodiment), or with or without other features of the case Used in various combinations with components.

<p>AP. . . Access point</p><p>DRI. . . Guided re-association instructions</p><p>DRCf. . . Re-association confirmed by guidance</p><p>DRCm. . . Guided re-association instructions</p><p>DRRq. . . Guided reassociation request</p><p>DRRsp. . . Guided re-association response</p><p>DS. . . Distribution system</p><p>WTRU. . . Wireless transmitting/receiving unit</p>

Figure 1 is a schematic diagram illustrating a system outline for WLAN communication.

Figure 2 is a schematic diagram showing the system according to this case, in which a mobile WTRU is leaving the service area of the original access point AP and is entering the service area of a target access point AP.

Figure 3 shows a schematic diagram of the handshake of the first scheme, in which an original AP requests the WTRU to handover to the target AP.

Figure 4 shows a schematic diagram of the handshake of the second scheme, in which an original AP instructs the WTRU to handover to the target AP.

Figure 5 shows a schematic diagram of the handshake of the third scheme, in which a target access point AP commands the WTRU to handover to a target access point AP.

Figure 6 shows a schematic diagram of the handshake of the fourth scheme, in which a target access point AP requests the WTRU to handover to a target access point AP.