Method and system for delivery of assistance data

Method and system for the delivery of help data.

FIELD OF THE INVENTION The present invention relates to wireless communication systems. More particularly, the present invention relates to the delivery of support data to wireless transmission / reception units (WTRU).

BACKGROUND Referring initially to Figure 1, a conventional wireless communication system 100 is shown. System 100 includes at least one wireless transmission / reception unit (WTRU) 102, an access point 104, and at least one system controller 106 for controlling and otherwise managing communications within system 100. Typically, in wireless local area network (WLAN) type systems, the network can be deployed as shown in Figure 2.

In Figure 2, the wireless network 200 comprises a system controller 206, a plurality of access points 214, 216, and a plurality of WTRU 212, 218. The WTRU 212, 218 are grouped with their respective access points 214, 216. These groupings are commonly referred to as basic service sets (BSS) 220, 222. A plurality of BSS 220, 222 are typically connected by means of a distribution system (DS) 224 in which a plurality of BSS is commonly referred to as an Extended Service Set (ESS). Access points 214, 216 are preferably connected to system controller 206 over a network 219.

Generally, the help data is data provided, or if made otherwise accessible at a particular access point, to the WTRUs associated with a particular access point. Typically, the help data may include any type of data that refers to any type of information related to the access points neighboring the specific access point (i.e., access points whose respective coverage areas are adjacent to the area coverage of the specific access point). Providing help data facilitates the issuance of the ringtone / handover of the WTRUs by providing them with essential information regarding finding / identifying neighboring access points.

By way of example, the help data may include information regarding neighboring access points such as the operating frequency of the neighborhood WTRUs and the access points, the access modes (for example,

802.11 Spectrum Spectrum with Frequency Hops (FHSS) / Spectrum Spectrum Direct Sequence (DSSS), 802.11a, 802.11b Spectrum Spectrum Wide Sequence with High Transfer Rate (HR-DSSS) etc.], synchronization information, configuration of the system in relation to neighboring basic sets (BSS) (for example, ready to transmit (RTS) / free to transmit (CTS), Point Coordination Function (PCF), Privacy equivalent to that of Cable Systems (WEP) , etc.].

Currently, help data is transmitted using point-to-point signaling (i.e. unicast). In 802xx type systems, for example, help data is provided in the form of an information element (IE) that contains the neighborhood information. IE is incorporated into the existing Probe Response frame. The Probe Response frame is typically sent by an access point in response to a Probe Request management frame sent by a WTRU when the WTRU attempts to discover the neighboring BSS. This arrangement is ineffective, however, because the transmission of help data using point-to-point signaling results in significant amounts of network traffic, thereby significantly increasing the likelihood of significant delays not only with respect to transmission. / reception of help data, but also with regard to transmissions / receptions in general.

As an example, US 6,246,673 describes a method and system that allows a faster determination of the synchronization of the system of a target base station in a mixed network of synchronous and asynchronous base stations. Particularly, a base station sends a neighborhood list that includes identification characteristics of the forward link of each of the neighborhood base stations to a mobile station. The neighborhood list contains a compensated pilot signal for each base station in the neighborhood list that the mobile station can use to distinguish forward coupling signals emanating from any base station in the neighborhood list. The mobile station receives the information such as the neighborhood list according to a transfer procedure. In this example, the transmission / reception of the neighborhood list may also be subject to significant delays.

Therefore, it would be desirable to provide a method and system to provide WTRU with help data without the limitations discussed above.

SUMMARY The present invention, as defined in claims 1 to 21, relates to an access point (AP), a wireless transmission / reception unit (WTRU), and a method and system for providing help data to wireless transmission / reception units (WTRU). The help data includes information regarding the neighboring access points of an access point. Help data is transmitted to WTRUs

using the type of multicast and / or broadcast signaling and facilitate the sending of the ringtone and transfer of the WTRUs from one access point to another.

In the documentation entitled “3rd Generation Partnership Project: Technical Specification Group Radio Access Network: Radio Resource Control (RRC) protocol specification (Release 1999)” dated June 1, 2003 (3GPPP TS 25.311 V3.15.0) and developed within the framework of the third generation cooperative projects, the dissemination of system information from the UTRAN to user teams is described. The document describes in particular that system information is organized as a tree in which a master information gives references and programming information to a number of blocks of system information in a cell.

In addition, a control channel management scheme that includes a variety of different cells is described in US 5353332. In particular, this document describes that the control channel of each cell can be configured for the dissemination of information about other cells that include the characteristics of the cells such as the cell type.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 is a block diagram of a conventional wireless communication system.

Figure 2 is a block diagram of a conventional wireless communication system that has

a plurality of access points and a plurality of WTRU.

Figure 3 is a block diagram of a wireless communication system according to the

present invention

Figure 4 is a diagram of the neighborhood information that is transmitted by an access point in a

predetermined multiple of the period of time with which the access point transmits its radio signals.

Figure 5 is a diagram of the neighborhood information that is transmitted along with a radio signal under the

form of an extended radio signal in a predetermined multiple of the period of time with which the point

Access transmits its regular radio signals.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Although the features and elements of the present invention are described in the preferred embodiments in concrete combinations, each feature or element may be used alone (without the other features and elements of the preferred embodiments) or in various combinations. with other features and elements of the present invention or without them.

Here, a wireless transmission / reception unit (WTRU) includes, but not limited to, a user equipment, mobile or fixed subscriber station, search engine, or any other type of device capable of operating in a wireless environment. When reference is made here, an access point includes, but is not limited to, a base station, Node-B, site controller, access point or any other type of interconnection device in a wireless environment. Here, the term handover includes changing access points while a WTRU is actively receiving / transmitting data and the term ringtone sending includes changing hotspots while a WTRU is not actively receiving / transmitting data. The present invention also applies to both scenarios and the terms "handover" and "send ringtone" can be used interchangeably here, so that both terms refer generically to situations in which a WTRU affiliated with a first access point or that works otherwise with it becomes adopted by a second access point and its affiliation with the first access point is terminated eventually.

In general, in the present invention, access points obtain help data using OAM, inter-access point signaling, scanning, ordering WTRUs to explore, or a combination of these operations and transmit this information as a just message to a plurality of WTRU. Once it has been obtained, an access point can also share the neighborhood formation with other access points allowing those access points to also transmit the information to the WTRUs.

Referring now to Figure 3, it shows a wireless communication system 300. System 300 includes at least one extended service set (ESS). For the purposes of describing the present invention, however, two ESS 336, 338 are shown in Figure 3. The first ESS 336 is configured in accordance with the present invention and includes a system controller 302, a plurality of access points 304, 306, 308, and a plurality of WTRU 310, 312, 314. Of course, the first ESS 336 could be configured with a single access point, when appropriate, in which case it could be called a BSS. The total coverage area of ​​the first ESS 336 is contoured in thick lines and includes coverage areas 324, 326, 328. The second ESS 338 also includes a system controller 316, a plurality of access points 318, 320, 322, and a plurality of WTRU (not shown). The total coverage area of ​​the second ESS 338 includes coverage areas 330, 332, 334.

In the present invention, access points 304, 306, 308 of the first ESS 336 each include processors 340, 342, 344 to obtain help data and provide them to their respective WTRU. Help data facilitates the delivery and sending of WTRU ringtones. It is observed that only the first ESS 336

It is shown configured in accordance with the present invention for the sake of simplicity in the description of the invention. Of course, any number of access points irrespective of their affiliation with an ESS or a BSS can be configured in accordance with the present invention.

Help data (i.e. neighborhood list or neighborhood information) is preferably obtained by operation and maintenance (OAM), owner signaling between access points (i.e. inter-access point signaling), active scanning / passive channels other than the one being used by the access point of the scan, and / or measurement reports of the WTRU. The method used to obtain the neighborhood information may vary depending on the neighborhood access point for which the information is sought.

For example, in Figure 3, when the access point 304 is seeking information with respect to the access points 306 and 308 within the same ESS 336 of the access point 304, it may be preferable to use the inter-access point signaling and / or it may be preferable to do so because, for example, access points 304, 306, 308 share a common system controller 302 that allows providing neighborhood information in relation to access points 306, 308 to access point 304 through controller 302. Inter-access point signaling may be preferable because, for example, although direct connections are shown between access points 304, 306, 308 for the sake of simplicity, It typically provides a distribution network as shown in Figure 2 between access points 304, 306, 308 that make up an ESS 336. The distribution network provides direct connections established by wires on which the signaling of inter-access points can be performed efficiently. When using inter-access point signaling, the Inter-Access Point Protocol (IAPP) can be used.

As mentioned above, other options are also available for access point 304 to obtain the neighborhood information of neighboring access points 306, 308. For example, access point 304 may order WTRU 310 to scan channels with except for the one being used by access point 304 to obtain the neighborhood information for any channels that are detected and the return information communicated. Access point 304 can also scan for other channels by itself. In cases where access point 304 is scanning, such a scan can be done independently or in conjunction with any scan that is done by WTRU 310. In this embodiment, a quality metric can be used, for example the energy received, to choose between the measurements obtained by the access point 304 against the measurements obtained by the WTRU 310 for the same channel.

In the case where the access point 304 is obtaining the neighborhood information in relation to an access point 318 that may happen to be outside the ESS 336 of the access point 304, it may be preferable to obtain the information by scanning. As discussed above, access point 304 can perform the scan (either passively or actively) by itself or order the WTRU 310 to conduct the scan (either passively or actively) and report back. Of course, access point 304 is not limited to using the scan to obtain neighborhood information with respect to access point 318. Access point 304 can also obtain information in relation to access point 318 using signaling of inter-access point.

The processor 340 of the access point 304 is preferably configured to obtain the neighborhood information as described above. Of course, more than one processor can be used, as desired. The information obtained by processor 340 can be stored in memory 350, as needed. In addition, the processor (s) 340 of access point 304 is also configured to provide the neighborhood information as explained below.

It is noted that the various methods described above may be used in combination in cases where appropriate. For example, when an access point 304 initially comes online, and does not have defined neighborhood information through it, it can itself explore the surroundings and / or order some of its WTRU 310s to explore as well. Once access point 304 has the results of this scan, you can then use this information to inform other access points 306, 308 within your ESS 336 about the findings. This will minimize the amount of scanning (which may cause some small traffic disruption) performed by these access points 306, 308. This arrangement may be particularly useful in the event that point 304 searches for neighborhood information from an access point 318 outside of ESS 324 because the information of access point 304 will probably not include access points 318, 320, 322 outside the ESS 324. It is also noted that in a preferred embodiment, access point 304 should, after startup and discovery of neighborhood information, periodically scan (or ask one of its WTRUs to explore) to see if the status of the information on Neighborhood has changed.

The neighborhood information obtained by access point 304 is preferably or sent by multicast periodically to WTRU 310 operating within coverage area 336 of access point 304. Referring below to Figure 4, using WLANs. As an example, all access points and WTRUs operating within a specific BSS transmit and receive using a single channel (ie frequency). As shown in Figure 4, the access point periodically transmits a radio beacon 402 in its channel

respective. The period of time in which the beacon is transmitted is typically referred to as a beacon frame. Radio beacon 402 is typically transmitted approximately every 1OO ms. Although possible, it is not typically necessary for an access point to transmit the neighborhood information it has obtained to its WTRUs in each beacon. Therefore, in a preferred embodiment, the access points are configured to transmit their neighborhood information in predetermined multiples of the period of time between the transmissions of their radio beacon 402 by the access points. The multiple can be set as desired and is preferably a function of the degree of mobility of the WTRUs affiliated with their respective access point.

By way of example, in Figure 4, the neighborhood information 406 that is transmitted by an access point 4 in a particular multiple of the beacon range is shown. The specific access point that is transmitting neighborhood information 406 shares the channel with the WTRUs with which it is affiliated. Therefore, in a radio beacon interval in which the neighborhood information is being transmitted, once the access point has finished transmitting its beacon 402, it waits for a certain interval of time until it can access the channel again. This time interval is typically called the 404 containment phase because the access point is contending with its respective WTRUs for access to the channel. Once the access point gains access to the channel, it transmits neighborhood information 406 in which information about neighboring access points is provided, as explained above, to the WRLUs affiliated with the access point.

Neighborhood information 406 may be transmitted as a multicast message (s) to a predetermined group of WTRUs affiliated with the access point that is transmitting neighborhood information 406. In another embodiment, neighborhood information 406 may be disseminated to all WTRUs affiliated with the access point it transmits. It is noted that WTRUs, in parallel with the efforts of the access points to provide them with neighborhood information 406, can also use point-to-point probe requests and / or channel scanning. WTRUs can execute such techniques as a backup and / or complement to the reception of such information from the access point.

The neighborhood information 406 is preferably transmitted using a management type frame (ie, during a time interval in which the system management information is transmitted). The management type frame that is used, in one embodiment, is preferably the same as that used in the prior art when WTRUs obtain neighborhood information using point-to-point signaling. In addition, the associated procedures executed in a WTRU after receiving neighborhood information 406 are the same as those of a point-to-point message, except for acceptance by the WTRU.

Referring now to Figure 5, another embodiment of the present invention is shown. In this embodiment, the typical beacon signal is configured with an additional bit in which the additional bit indicates the presence / absence of neighborhood information. Radio beacons 502 normally transmitted within a regular beacon frame are shown with signaling bit 506 appearing empty. Radio beacons 502 are normally transmitted in a regular beacon frame by an access point according to a predetermined program. The periodicity with which neighborhood information is sent is a predetermined multiple of the time interval between transmissions of radio beacons 502, as discussed above. When it is time for the neighborhood information to be transmitted by an access point to their respective WTRUs, the neighborhood information 508 is added to the radio beacon 502 and transmitted along with it in an extended beacon frame

504 In this scenario, the signaling bit 506 of the radio beacon 502 is occupied to reflect the fact that the bit has been set in such a way that it indicates that the neighborhood information 508 is present within the extended beacon frame 504. In a preferred embodiment, the neighborhood information 508 is added to the beacon 502 as an information element (IE). As discussed above, neighborhood information 508 includes information that helps WTRUs efficiently transfer from an access point to a neighboring access point.

It is important to note that the present invention can be executed in any type of wireless communication system. By way of example, the present invention can be executed in wireless local area networks (WLAN), wireless personal area networks (WPAN), wireless metropolitan area networks (WMAN) or any other type of communication systems / wireless networks. In addition, although the features and elements of the present invention are described in preferred embodiments in particular combinations, each feature or element may be used alone or in various combinations with or without other features and elements of the present invention.

DETAILED LIST

Article 1. An access point to provide help data to the wireless transmission / reception units (WTRU), including the access point:

means for obtaining help data from at least one neighboring access point whose respective coverage areas are adjacent to the coverage area of ​​said access point; where said help data includes information to facilitate the transfer of a WTRU from said access point to said neighboring access point from which the help data has been obtained; and

means for said access point to periodically transmit said help data as a single

message to a plurality of WTRUs operating within the coverage area of ​​said access point. Article 2. The access point of article 1, in which the aid data is obtained by operation and maintenance (OAM).

Article 3. The access point of Article 1, in which the aid data is obtained by signaling between said access point and said neighboring access point.

Article 4. The access point of article 3, in which the signage is proprietary. Article 5. The access point of Article 3, in which the signaling is carried out using a protocol of the point of inter-access (IAPP).

Article 6. The access point of Article 1, in which the help data is obtained by exploring the channels with exception of that used by said access point. Article 7. The access point of article 6, in which the exploration is a passive exploration.

Article 8. The access point of article 6, in which the exploration is an active exploration. Article 9. The access point of Article 1, in which the aid data is obtained by making measurements for WTRUs operating within the coverage area of ​​said access point.

Article 10. The access point of Article 1, in which the aid data includes the operational frequency of the

WTRU and neighboring access points for which help data is obtained. Article 11. The access point of Article 1, in which the help data includes the access modes used by a neighboring access point for which help data is obtained.

Article 12. The access point of Article 1, in which the aid data includes information on the

synchronization for a neighboring access point for which help data is obtained. Article 13. The access point of Article 1, in which the help data includes configuration information for a neighboring access point for which help data is obtained.

Article 14. The access point of article 1, in which the aid data is transmitted in a predetermined multiple of a period of time with which a radio beacon is being transmitted by said access point.

Article 15. The access point of Article 14, in which the aid data is transmitted separately from the beacon.

Article 16. The access point of article 14, in which the aid data is transmitted together with the beacon. Article 17. The access point of Article 16, in which the aid data is aggregated in the form of a information element (IE) to the radio beacon in which said help data and the beacon are transmitted together.

Article 18. The access point of Article 1, in which the aid data is used to facilitate the sending of a

WTRU ringtone. Article 19. The access point of Article 1, in which the aid data is transmitted as a message of diffusion.

Article 20. The access point of Article 1, in which the aid data is transmitted as a message of

multicast Article 21. An access point to provide help data to wireless transmission / reception units (WTRU), comprising the access point:

at least one processor configured to obtain help data at at least one neighboring access point

whose respective coverage area is adjacent to the coverage area of ​​said access point; wherein said help data includes information to facilitate the transfer of a WTRU from said access point to said neighboring access point from which the help data was obtained; and

wherein said processor is further configured to transmit said help data as a single message to a plurality of WTRUs operating within the coverage area of ​​said access point.

Article 22. The access point of article 21, in which the aid data is obtained through operation and maintenance (OAM).

Article 23. The access point of Article 21, in which the aid data is obtained by signaling between said access point and said neighboring access point.

Article 24. The access point of article 23, in which the signage is proprietary.

Article 25. The access point of article 23, in which signaling is performed using an inter-access point protocol (IAPP).

Article 26. The access point of Article 21, in which the help data is obtained by exploring the channels with the exception of that used by that access point.

Article 27. The access point of article 26, in which the exploration is a passive exploration.

Article 28. The access point of article 26, in which the exploration is an active exploration.

Article 29. The access point of Article 21, in which the aid data is obtained by making measurements for the WTRUs operating within the coverage area of ​​said access point.

Article 30. The access point of Article 21, in which the aid data includes the operational frequency of the WTRUs and neighboring access points for which the aid data is obtained.

Article 31. The access point of Article 21, in which the aid data includes the access modes used by a neighboring access point for which the aid data is obtained.

Article 32. The access point of Article 21, in which the help data includes information on the synchronization for a neighboring access point for which the help data is obtained.

Article 33. The access point of Article 21, in which the help data includes configuration information for a neighboring access point for which the help data is obtained.

Article 34. The access point of Article 21, in which the aid data is transmitted in a predetermined multiple of a period of time with which a radio beacon is being transmitted by said access point.

Article 35. The access point of Article 34, in which the aid data is transmitted separately from the beacon.

Article 36. The access point of article 34, in which the aid data is transmitted together with the radio beacon.

Article 37. The access point of Article 36, in which the aid data is added in the form of an information element (IE) to the radio beacon in which said aid data and the beacon are transmitted together.

Article 38. The access point of Article 21, in which the help data is used to facilitate the sending of a WTRU ringtone.

Article 39. The access point of article 21, in which the help data is transmitted as a broadcast message.

Article 40. The access point of article 21, in which the help data is transmitted as a multicast message.

Article 41. A method for providing help data to WTRUs in wireless networks, the method comprising the steps of:

obtaining the help data at an access point, said help data being related to neighboring access points that have wireless coverage areas that are adjacent to the wireless coverage area of ​​said access point; and transmitting said help data periodically as a single message from said access point to a plurality of WTRU (310) operating within the wireless coverage area provided by said access point.

Article 42. A wireless communication system comprising:

at least one system controller;

5 a plurality of wireless transmit / receive units (WTRUs), which operate within a coverage area at least one first access point; at least one neighboring access point whose coverage area is adjacent to the coverage area of ​​the first access point;

10 wherein the first access point is configured to obtain the help data related to the neighboring access point to facilitate the transfer of the WTRU from the first access point to the neighboring access point; and wherein the first access point is further configured to transmit said help data as a single message to the plurality of WTRU.