Apparatus and method for selectably operating radio device in alternate operating mode

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DESCRIPTION

Apparatus and method for selectively operating a radio device in alternate operating mode.

The present invention generally relates to communications in a radio communication system, such as a WLAN (wireless local area network). More particularly, the present invention relates to an apparatus, and an associated method by means of which to identify whether proprietary WLAN radio functions are available for a mobile terminal-access point pair and to activate proprietary WLAN radio functions if such availability is identified. The operation of proprietary WLAN radio functions enables improved communication quality, such as improved handover operation, relative to conventional WLAN operation conforming, for example, to the IEEE 802.11 standard.

Background of the invention

A communication system is made up of at least one transmitting station and one receiving station interconnected by means of a communications channel. The communications signals generated by the transmitting station are transmitted over the communications channel to be received by the receiving station.

A radio communication system is a communication system in which at least a part of the communication channel is made up of a part of the electromagnetic spectrum. Increased mobility of communications is allowed as it is not required to form a fixed or wired connection between the transmitting and receiving stations.

A cellular communication system is an exemplary radio communication system. A subscriber to a cellular communication system, when located at almost any location in an entire area encompassed by the network infrastructure of the cellular communication system, is capable of communicating via the system with a mobile terminal.

The network infrastructure of an exemplary cellular communication system includes base stations spaced at fixed locations that include transceivers. In such an example system, each base station at a fixed site defines a cell. As the mobile terminal used by the subscriber to communicate with another communication station travels between cells in the system, seamless communication is possible by handover of communications from one base station to another.

Various analogous types of wireless communication systems have been implemented, and others have been proposed, to encompass limited areas, such as the area encompassed by a building structure or work offices. Wireless communication systems sometimes referred to as microcellular networks, private networks, and WLANs (wireless local area networks) are an example of such systems.

Wireless communication systems are typically built to standards promulgated by a regulatory or quasi-regulatory body. For example, the IEEE 802.11 standard promulgated by the IEEE (Institute of Electrical and Electronics Engineering) is a wireless LAN standard that generally belongs to the commercial 2.4 GHz wireless LAN (Local Area Network). The 802.11 standard specifies a radio interface between a wireless client, for example a mobile terminal, and a base station or access point, as well as between wireless clients. The standards that belong to a physical layer and a MAC (media access control) layer are declared in this standard. The standard allows automatic media sharing between different devices which includes compatible physical layers. Asynchronous data transfer is provided in the standard, usually as the MAC layer using a CSMA / CA (Collision Avoidance Carrier Multiple Access) communication scheme.

While the IEEE 802.11 standard provides wireless communications through the use of mobile terminals built to operate in accordance with that standard, the standard does not adequately provide real-time wireless services. For example, in the current implementation of the standard, a significant loss of quality is sometimes experienced during the handover of communications from one access point to another. The excessive number of data frames are susceptible to being lost or delayed, resulting in the loss of the quality of the communication or even the termination of the communications.

Therefore, operational modes different from those declared in the IEEE 802.11 standard are required, in particular for real-time wireless services. Proprietary functions have been proposed that allow for improved quality of communications compared to operation in accordance with the existing IEEE 802.11 standard. Access points and mobile terminals that can be operated to perform such proprietary functions are referred to as proprietary mode capable.

However, both ends of the communication pair, that is, the mobile terminal and the access point through which the mobile terminal communicates, must be capable of operating in the proprietary mode. If both ends of the communication pair are not jointly operable under proprietary mode, conventional IEEE 802.11 standard operation is required.

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Therefore, before allowing the operation of both ends of the communication pair in the proprietary mode, a determination must be made of the ability of both ends of the communication pair together to be able to operate in accordance with the proprietary mode.

A way is required by which to identify whether both ends of the communications pair can work together in the proprietary mode, to activate both ends of the communications pair to operate in the proprietary mode, and to maintain operation in the proprietary mode. owner during handover procedures from one access point to another. Furthermore, US-A-5 077 732 describes a selection of modes of operation by covering the information associated with the node identifiers. It is in light of this background information relating to wireless communications that significant improvements of the present invention have been developed.

Summary of the invention

The present invention accordingly advantageously provides an associated apparatus and method for identifying whether proprietary WLAN radio functions are available for a communication pair consisting of a mobile terminal and an access point.

The present invention further advantageously provides an apparatus and an associated method, to initiate the activation of the proprietary WLAN radio functions after identifying that both the mobile terminal and the access point of the communication pair can work together in accordance with the proprietary WLAN radio function.

The present invention advantageously further provides an apparatus and associated method by which to maintain a proprietary communication mode during handover of communications from one access point to another.

In one aspect of the present invention, a way is provided to identify whether devices built to operate on a WLAN, such as those defined in the IEEE 802.11 standard, can also operate together under the proprietary mode of operation to perform proprietary WLAN radio functions. Such proprietary WLAN radio functions are intended to improve the quality of communications relative to the quality of communications provided during operation in accordance with a conventional IEEE 802.11 mode of operation.

In a further aspect of the present invention, in response to the identification that both ends of a communication pair consisting of a mobile terminal and a WLAN access point can work together under the proprietary mode, the mobile terminal is enabled to operate in proprietary mode instead of the conventional IEEE 802.11 mode of operation. Improved communication quality relative to that allowed mode under conventional IEEE 802.11 standard operation is possible after this.

In a further aspect of the present invention, a way is provided to ensure that better communication than ongoing communications by a peer will continue to perform in proprietary mode after handover of communications from one access point to another access point. of communications that works according to the proprietary operation mode In one implementation, the mobile terminal of the communication pair is provided with a list of access points that are capable of operating in proprietary mode. The list, a list of neighboring APs (Access Points), is used by the mobile terminal or by the network, in determining which access point this handover of communications is allowed to. Since handovers are only allowed between proprietary mode capable access points if the handover is performed to only one access point in the list, it is further ensured that communications will continue to be performed in accordance with the proprietary mode of operation and therefore provided. In one implementation , the list is provided to the mobile terminal at selected intervals. In another implementation, the list is provided to the mobile terminal when the mobile terminal is initially activated to be able to operate according to the proprietary mode. Also, in another implementation, a network prefix or list of network prefixes is provided for the same purpose.

In one implementation, an EUI-64 type of MAC (media access control) layer address is provided to each of the devices that can operate on the WLAN. The EUI-64 type address consists of two fields, a company id field and a CDPD M-ES (cellular digital packet data - mobile end system number) field. This address is globally unique. Before conducting communications, the EUI-64 MAC addresses of a communications pair consisting of a mobile terminal and an access point are compared to identify whether both devices are proprietary mode capable. If both devices are determined to be proprietary mode capable in response to the comparison, communications are allowed under the proprietary mode. The mobile terminal is activated after this so that it can operate according to the proprietary mode, and an improved communication quality of subsequent communications is possible. Also, when the handover of communications is to be carried out, the handover is effected, if possible, only to a subsequent access point that is also proprietary mode capable. Continued communications of improved quality levels relative to conventional communications conforming to the IEEE 802.11 standard are therefore possible.

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In these and other aspects, therefore, an apparatus and associated method are provided for a radio communication system having a mobile terminal and at least one access point to allow access to the communication of the mobile terminal with the network infrastructure. The mobile terminal and the access point together may operate in a first mode and potentially together they may operate in a second mode. The mobile terminal and the at least one access point are each identified by unique identifiers. The identification is made if the mobile terminal and the access point can work together according to the second mode. A comparator is coupled to receive indications of the identifier that identifies the mobile terminal. The comparator is also coupled to receive indications of the identifier that identifies the access point. The comparer compares values ​​of the identifiers. The comparator indicates the mobile terminal and the access points together so that they can operate according to the second mode if the values ​​of the identifiers indicate that both the mobile terminal and the access point are capable of operating according to the second mode. And, the comparator indicates the mobile terminal and the access point together so that they can function only according to the first mode if the identifier values ​​fail to indicate both that the mobile terminal and the access point can function according to the second mode.

A more complete appreciation of the present invention and the scope thereof can be obtained from the accompanying drawings which are briefly summarized below. The following detailed description of the presently preferred embodiments of the invention and the appended claims.

Brief description of the drawings

Figure 1 illustrates a functional block diagram of a communication system in which an embodiment of the present invention can operate.

Figure 2 illustrates a representation of a MAC (media access control) layer address used to identify devices that may operate in the communication system shown in Figure 1 in accordance with one embodiment of the present invention.

Figure 3 illustrates a sequence diagram illustrating signal sequencing between a mobile terminal and an access point during operation of an embodiment of the present invention.

Figure 4 illustrates a procedure flow diagram listing a procedure of operation of an embodiment of the present invention.

Detailed description of the preferred embodiment

Referring first to Figure 1, a communication system, shown generally at 10, provides radio communications with mobile terminals, of which mobile terminal 12 is an example. In the exemplary implementation, the communication system 10 forms a WLAN (wireless local area network) that provides radio communications with the mobile terminal as stated in the IEEE 802.11 standard also, potentially, conforming to a proprietary mode of operation. Other communication systems may be represented analogously, and the operation of an embodiment of the present invention is analogously operable in other such communication systems as well.

In a conventional manner, the WLAN includes a plurality of spaced access points (AP) 14 positioned at spaced locations. Two access points are shown in the figure. In a real WLAN, typically, larger numbers of access points 14 are used. Access points 14 are sometimes referred to as base stations or RADs (remote antenna devices). The term "access point" will generally be used in this document to identify such devices as the devices that form the access points to the network infrastructure of the communication system.

The access points 14 include radio transceiver circuitry 16 capable of transmitting / receiving radio communication signals with mobile terminals when the mobile terminals are positioned within a communication range of the access points. Generally, a mobile terminal communicates with an access point 14 when the mobile terminal is positioned within an area, referred to as a cell 18, close to and defined by the access point. The figure illustrates a cell 18 associated with each of the illustrated access points.

Access points 14 are shown in this document to be coupled to a central control unit (CCU) 22. CCU 22 provides functions to control various aspects of WLAN operation. And, as shown, the CCU 22 provides connections to a trunk of an external communication network 24. Although not shown separately, other communication devices, such as other communication stations and other communication networks are typically coupled to the trunk line of the communication network 24. Therefore, a path of communications to provide communications between the mobile terminal 12 and the coupled communication stations, or directly or indirectly to the trunk line of the communication network. Also, local communications between mobile terminals 12 are allowed. In communications between pairs of mobile terminals, the communication path formed between them includes two independent radio links.

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In the example implementation, the access points 14 include control elements 28. The control elements 28 perform various control functions related to the operation of the respective access points. Here, the control elements are each shown to include a comparator 32, a mode selector 34, and a handover availability determiner 36. Such elements are functional and implemented in a desired manner, such as, for example, algorithms executable by means of processing circuitry of which the control element is formed in the example implementation. In another implementation, the functions performed by said elements are located somewhere else, such as in the mobile terminal, indicated by block 28 'or in the CCU 22, indicated by block 28 ", also shown in dotted line. And, the functions performed by the elements can also be distributed among several different devices.

As noted above, due to the various shortcomings of the IEEE 802.11 standard, the quality of communication between the mobile terminal and an access point during the operation of, for example, real-time wireless services, the mode proprietary operation, if available, is preferred for IEEE 802.11 conventional standard operation. However, the communication operation between a mobile terminal and an access point according to the proprietary mode of operation requires that both the access point and the mobile terminal can be operated according to the proprietary mode. The operation of an embodiment of the present invention identifies whether both elements of the communication pair, that is, the access point and the mobile terminal, can work together according to the proprietary mode. When both elements of the communication pair are identified as capable of proprietary mode, operation of the communication in accordance with proprietary mode is permitted.

The comparator 32 can be operated here to receive indications of identifiers that identify both the mobile terminal and the access point forming the communication pair. Sensitive to comparisons made by the comparator, the communications pair is identified as capable of proprietary mode or merely conventional, capable of IEEE 802.11 mode.

Sensitive to the identification made by the comparator, the mode selector 34 may function to select the mode of operation by which to carry out communications between the mobile terminal and the access point. If the communication pair is determined to be proprietary mode capable, then it is generally preferred that the communications be conducted in proprietary mode. In the example implementation, once the selection is made by means of the mode selector, a command signal is broadcast to the mobile terminal to command the mobile terminal to become activated in the proprietary mode. And, the mobile terminal returns an acknowledgment once the mobile terminal has become active in the proprietary mode.

As the position of the mobile terminal changes, the mobile terminal could leave a cell and enter another cell, handover of communications from the access point associated with the first cell to the access point associated with the cell. The cell you have just entered is generally performed to allow continued communication with the mobile terminal. The handover availability determiner may operate in accordance with an embodiment of the present invention to provide indications to the mobile terminal of available access points to which handover of communications is possible. In the exemplary implementation, when the mobile terminal and the access point communication pair can operate according to the proprietary mode of operation, the determiner 36 generates a list of available access points 38 containing the identities of the access points that They are capable of proprietary mode and available for the handover of communications to them. When the available access points to which handover is allowed consist only of access points capable of the proprietary mode, the handover of communications to an access point compliant with the proprietary mode is therefore ensured. The access point list 38, in one implementation, communicates to the mobile terminal at selected intervals. In another implementation, the list of access points is provided to the mobile terminal when the mobile terminal is initially activated within the proprietary mode. And, in another implementation, a network prefix, or list of network prefixes, is used to accomplish the same goal.

Returning now to FIG. 2, a MAC (media access control) layer address 42 used during operation of one embodiment of the present invention is shown. The MAC layer address is of type EUI-64. The address consists of two fields, a company id field 44, and a CDPD M-ES (cellular digital packet data - mobile end system number) field 46. Each of the fields 44 and 46 is of a length twenty-four bits. The fields are defined in an existing cellular digital packet data systems specification.

The twenty-four most significant bits that make up the company id field 44 are assigned by an IEEE registration authority (IEEE RAC) to a specific manufacturer. Therefore, company id 44 uniquely identifies the manufacturer of a device. And, a CDPD M-ES field is a number assigned by the manufacturer to a particular device to identify the device. Due to the length of field 46, approximately sixteen million unique values ​​of address 42 are possible by varying the final twenty-four bits of the address, that is, the content of field 46. Conventionally, an id of additional company for a manufacturer when approximately ninety percent of the address values ​​of the sixteen million available addresses have been used with a single company. As a result of this, each address 42, made up of the company id and CDPD M-ES fields 44 and 46, is globally unique.

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Values ​​of the addresses that identify the access point and the mobile terminal that form a communication pair are provided to the comparator 28 and the comparator can function responsively thereto to identify whether the mobile terminal and the access point that form the communication pair. communications are jointly compliant with the proprietary mode. When the comparator is positioned on the access point, it is already known that the access point is or is not capable of proprietary mode. An independent analysis of the address of the company id can be omitted in such an embodiment.

Only parts of the address may need to be compared. For example, if all products made by a manufacturer are capable of proprietary mode, the mode can be identified based only on the analysis of the company id fields of the addresses. If, however, only some devices made by a manufacturer are capable of proprietary mode, the fields 46 must be analyzed to determine if the particular device is capable of proprietary mode.

In one implementation, the mobile terminal enters the proprietary mode of operation upon selection by the mode selector of the access point and communication with the mobile terminal of the selection by means of a MAC layer message. During mobile registration, the access point inspects the mobile terminal's MAC layer address, along with the access point's layer address to determine if the communication peer supports proprietary mode operation. After the determination, the access point instructs the mobile terminal to enter the proprietary mode by means of a proprietary MAC message or proprietary encoding in a standard message. In alternative implementations, the message is implemented at the network level and the signaling is appropriately altered. Also, in an implementation where comparisons are made at the mobile terminal, the signal link is again appropriately altered.

Figure 3 illustrates a sequence diagram, shown generally at 52, representative of signaling between a mobile terminal 12 and an access point 14 that together form a communication pair. First, and as indicated by segment 56, the mobile terminal sends a standard IEEE 802.11 association message to the access point. The association message includes the MAC layer address 42, unique to the mobile terminal. The access point may function, as noted above, to analyze the value of the MAC layer address of the mobile terminal to identify whether the access point and the mobile terminal together can operate under the proprietary mode. In one implementation, since the comparisons are made at the access point, the ability of the access point to operate in accordance with proprietary mode is biased, that is, already known.

Here, the mobile terminal and the access point can work together according to the proprietary mode and the access point generates a command, indicated by segment 58, to instruct the mobile terminal to self-activate in order to operate according to the proprietary mode . And, as indicated by segment 62, the mobile terminal confirms activation and indicates the exact nature of the proprietary mode, eg, mode B, phase 4.

The sequence diagram further illustrates the transmission, indicated by segment 66, of the AP list 38 to the mobile terminal. When the mobile terminal leaves a cell and enters another cell, a handover request is generated, indicated by segment 68, and, if appropriate, the handover request is guaranteed, which is indicated by segment 72.

Figure 4 illustrates a procedure, generally shown at 82, that lists the procedure steps of the procedure of operation of an embodiment of the present invention. The method identifies whether a mobile terminal and an access point, together forming a communication pair, can operate together in a proprietary mode.

First, and as indicated by means of block 84, the values ​​of the identifier identifying the access point and the identifier identifying the mobile terminal are compared.

Sensitive to this, and as indicated by block 86, the mobile terminal and the access point are identified together as being able to operate under the proprietary mode if the identifiers indicate that the mobile terminal and the access point together can operate under the proprietary mode. to owner mode. Otherwise, and as indicated by block 88, the mobile terminal and the access point are identified together as being capable of operating in a conventional IEEe 802.11 mode.

Therefore, through the operation of an embodiment of the present invention, a way is provided to identify whether a communication pair consisting of a mobile terminal and an access point is capable of operating in the proprietary mode, a way is provided by means of which to activate the mobile terminal so that it can operate according to the proprietary mode, and a way is provided by which to better ensure that the mobile terminal will continue to communicate in accordance with the proprietary mode during and after the handover of communications.

The above descriptions are of preferred examples for implementing the invention, and the scope of the invention should not be necessarily limited by this description. The scope of the present invention is defined by the following claims.