GB2484115A

GB2484115A - Selecting an optimum access point based on location

Info

Publication number: GB2484115A
Application number: GB1016415.0A
Authority: GB
Inventors: Santosh Singh; German Jose D Jesus Bencci
Original assignee: Samsung Electronics Co Ltd
Current assignee: Samsung Electronics Co Ltd
Priority date: 2010-09-30
Filing date: 2010-09-30
Publication date: 2012-04-04
Anticipated expiration: 2030-09-30
Also published as: GB201016415D0; GB2484115B

Abstract

Operating a mobile device 1 to selectively connect to a wireless network, comprising the steps of: monitoring the location of the mobile device, e.g. using GPS module 50; determining if the location is a known location; if the location is a known location, determining if there are known wireless network access points 4 associated with the location; and if there are known wireless network access points (hot-spots) associated with the location, selecting the best access point on the basis of a predetermined criterion, and enabling a wireless network transceiver to initiate communication with the selected access point. If no access points are available in a known area the wireless network transceiver is disabled to save power and battery life. Access points in the local vicinity are identified using local database 40 or remote database (45, figure 2). A Quality Indicator for each access point may be calculated based on an average Received Signal Strength Indicator (RSSI) and an average Signal-to-Noise Ratio (SNR) for each access point. The access points may include Wi-Fi, WiMax or EvDo.

Description

Improvements in Network Selection

BACKGROUND

Technical Field

The present invention is concerned with the ability of a mobile wireless device, such as a mobile telephone, PDA or laptop to access a wireless Access Point (AP), providing access to a network, such as the Internet.

Description of Related Art

Many mobile devices are capable of connecting to an Access Point, which may be provided in a public place, such as an airport, coffee shop, shopping mall or other publicly accessible area. Many people are able to access APs in their own homes or places of work also. Typically, over time, a user may access many different APs in different physical locations.

Some APs may be publicly accessible to all and others may be accessible only if a suitable login and/or password is provided.

Prior art mobile devices are typically arranged to connect to one amongst any available APs at a given location. The AP selected is typically the one having the strongest signal strength as measured at the mobile device. Alternatively, the user may be presented with a list of available APs and be asked to select one of them, with no further information typically being available.

The wireless protocol used to access the AP may be any suitable protocol such as, but not limited to, Wi-Fi (IEEE8O2.11), WiMax or EvDo.

SUMMARY OF THE INVENTION

According to a first aspect of the present invention there is provided a method of operating a mobile device, said mobile device being operable to selectively connect to a wireless network, the method comprising the steps of: monitoring the location of the mobile device; determining if the location is a known location; if the location is a known location, determining if there are known wireless network access points associated with the location; and if there are known wireless network access points associated with the location, selecting the best access point on the basis of a predetermined criterion, and enabling a wireless network transceiver to initiate communication with the selected access point.

Preferably, the wireless network can be one of: Wi-Fi; WiMax; 3G; 4G; EvDo; or any suitable wireless data network.

Preferably if the location is a known location and there is no known access point associated with the location, then disabling the wireless network transceiver.

Preferably if the location is an unknown location: enabling the wireless network transceiver to scan for wireless network access points in the vicinity; if wireless access points are detected, storing details relating thereto and initiating communication with the best one of the detected access points on the basis of the predetermined criterion.

Preferably if the location is an unknown location: fetching information from a remote server relating to access points associated with the location; storing fetched information relating to the access points; enabling the wireless network transceiver and initiating communication with the best one of the access points on the basis of the predetermined criterion.

Preferably if no access points are either detected or fetched from the server, then storing information relating to the absence of access points associated with the location and disabling the wireless network transceiver.

Preferably the predetermined criterion for selecting the best access point is evaluated in advance.

Preferably the predetermined criterion evaluates access points at a given location on the basis of one or more of: failed data frames; re-transmitted data frames; successful data frames; average RSSI; SNR; data rate; chipset compatibility; age of stored data relating to a particular access point; and current signal strength.

Preferably the default condition of the wireless transceiver is disabled.

Preferably the location of the mobile device is determined on the basis of GPS data.

Preferably the step of enabling the wireless network transceiver to scan is commenced automatically or as a result of a user instruction.

According to a second aspect of the present invention, there is provided a mobile device comprising a wireless network transceiver for communicating with a wireless network, and further comprising: a location determining unit, arranged to determine a present location of the mobile device; an access point selector unit, arranged to select the best wireless network access point from amongst a list of known access points associated with the present location, according to a predetermined criterion; and a controller, arranged to control the wireless network transceiver such that if there are no wireless network access points associated the present location then the wireless network transceiver is disabled or, alternatively, to initiate communication with the selected best wireless network access point.

Preferably if the location determining unit determines that the present location is a previously unknown location, the access point selector unit is arranged to either scan for wireless network access points in the vicinity or to fetch information from a remote server relating to access points associated with the location.

Preferably the controller is arranged to selectively remove the power supply to the wireless network transceiver to disable it.

Preferably the mobile device comprises a local data store for storing information related to one or more wireless network access points at a plurality of known locations.

According to a third aspect of the present invention, there is provided a tangible computer readable recording medium having recorded thereon instructions which, when executed, cause a computer to perform a method according to the first aspect.

Other features of the invention will be apparent from the dependent claims, and the

description which follows.

BRIEF DESCRIPTION OF THE DRAWINGS

For a better understanding of the invention, and to show how example embodiments may be carried into effect, reference will now be made to the accompanying drawings in which: Figure 1 shows a functional block diagram of a mobile device and network environment according to an embodiment of the present invention; Figure 2 shows a functional block diagram of a mobile device and network environment according to another embodiment of the present invention; Figure 3 shows a flowchart illustrating the operation of an embodiment of the present invention; and Figure 4 shows a schematic representation of a mobile device according to an embodiment of the invention moving between locations.

DETAILED DESCRIPTION OF THE EXAMPLE EMBODIMENTS

Figure 1 shows a block diagram of certain components of a mobile device I according to an embodiment of the present invention. The mobile device I shown in Figure 1 is a mobile telephone, but could be any mobile device having wireless communication capability. Other devices may include, but are not limited to, a laptop computer, a tablet computer or a Personal Digital Assistant (PDA).

The mobile device I is operable to communicate with a cellular network 2 using one or more known protocols, such as GSM, UMTS or 3G. The mobile device 1 is further operable to communicate wirelessly so as to connect with another network 3, such as the Internet, via an Access Point (AP) 4. Wireless access is achieved, in this example, by means of Wi-Fi (IEEE 802.11), but other protocols could be used.

The mobile device comprises a Wi-Fi transceiver module 10, which includes the necessary RF circuitry and antenna to propagate and receive Wi-Fi radio signals. The Wi-Fi transceiver module 10 is operably connected to and controlled by a Wireless LAN Connection Manager (WCM) 20. Some form of WCM is known in prior art devices, but the WCM included in embodiments of the present invention differ as will be described shortly.

The WCM is operably connected to Access Point and Power Management (ACPM) module 30, which is operable to control access to Access Points. This control is achieved by use of a local AP database 40, and in conjunction with location information provided by (Global Positioning by Satellite) GPS module 50.

When the mobile device I attempts to access the Internet 3 using Wi-Fi, the WCM is operable to control the Wi-Fi transceiver module 10. If the access point and power management' function is enabled, either automatically or manually by the user, then the ACPM module 30 is operable to manage which AP is accessed by the mobile device.

As mentioned previously, in prior art systems, the AP at a particular location having the highest signal strength is usually selected for connection. However, for reasons such as faulty devices, incompatibility issues between the AP and the device and the age of the equipment, the AP offering the strongest signal does not always offer the best quality of connection. The quality of connection may be assessed in a number of ways including number of failed frames and re-transmission count. Other measures such as data throughput can be used also.

Measures of AP quality will be described later.

Embodiments of the present invention use the APCM 30 to maintain a database 40 which includes information linking APs at or near a particular location to a quality indicator (01), indicative of the quality of an AP. The 01 represents the ability of an AP to offer a reliable AP, rather than merely a strong signal. The strength of a signal does not, alone, guarantee a good service for the reasons set out before.

Typically, a user may access a relatively small number of different APs in his day to day routine, particularly when located at one of a small number of regularly visited locations. For instance, when at home, he is likely to connect to his home Wi-Fi service. When at the office, there may be a number of different Wi-Fi services available, some of which may be closed proprietary systems and some of which may be publicly accessible ones. Also, when taking a coffee at a favourite coffee shop, a number of different Wi-Fi services may be available from the coffee shop or from other nearby establishments. In each case, the user wishes to make sure that a reliable and high quality connection is made. This is especially true if real-time applications, such as video-streaming or VoIP calls are being made, where a good, fast and reliable connection is essential or, at least, highly desirable.

Embodiments of the present invention control the operation of the Wi-Fi transceiver 10 such that it is not enabled unless there is a known AP in the vicinity which offers an acceptable level of service, Of course, if the user is in an unknown location, then the mobile device is able to select a new AP, as will be described shortly. However, most users tend to predominantly use only a few APs, and by disabling the Wi-Fi transceiver in locations where there is no acceptable level of connection to an AP can offer savings in battery life. In a preferred embodiment, the Wi-Fi transceiver 10 defaults to a disabled or powered-down state unless there is a known acceptable AP in the vicinity.

When a user enables Wi-Fi, perhaps by starting an application which requires a Wi-Fi connection or by manually enabling it, the WCM 20 checks to see if access point management has been enabled. If so, the APCM acts to read a list of known APs in the vicinity of the mobile device from the database 40. If it is determined that there is a known AP in the vicinity, then the Wi-Fi transceiver 10 is switched on, and connection is established with a known acceptable AP. The connection with the known AP is maintained until the user ceases needing it, by stopping the associated application or manually disabling the connection.

When the user attempts a Wi-Fi session in a known location, the APCM acts to get a list of known APs in the vicinity, as stored in the local database 40. If this reveals that there is at least one known AP, then the Wi-Fi transceiver 10 is enabled or powered up. At the same time, a location timer is started and, once connection is made with an AP, an RSSI timer is started. The location timer is provided so that once it expires after a certain time, the device will seek to re-determine its location, to ensure that if the user moves, a new AP may be required. The RSSI timer is provided so that the measured RSSI of the connected AP may be determined periodically.

When the location timer expires, the APCM checks for access points in the vicinity, based on the current location. Having identified those in the vicinity, the AP with the highest 01 is selected according to a predefined algorithm. The AP with the best 01 and a satisfactory signal strength is then selected for connection. If there is no suitable AP in the vicinity, then the Wi-Fi transceiver 10 is disabled to save power.

If the location timer expires whilst connected to an AP, then various link metrics are fetched and stored in the local database 40 to ensure that its records of known APs is maintained and kept current. The link metrics which are fetched may include one or more of MAC address, ssid, successfully transferred frames, failed frames, duration. Also, the average RSSI and SNR may be calculated since the previous timer location expiry, and these can be stored in the database 40 too. In this way, the data in the database regarding known APs can be periodically refreshed to ensure it is still valid and useful.

Once the Wi-Fi connection is terminated, then the location and RSSI timers are stopped and the database may be updated as described.

The local database 40 stores a variety of information concerning known APs. This data may be summarised as shown in Tables 1 and 2, which follow. Table 1 is the list of all APs known to the mobile device. It includes nine different fields with the fields holding data as set

out in the Description, column.

Field Field Name Description

1. macAddress This is MAC address of the Access Point 2. ssid This is SSID broadcasteby the Access Point 3. apLocation This is the approximate location of the Access Point 4. timeStamp Time stamp when device was connected 5. beaconlnterval This is the beacon interval of access point to which device is connected.

6. listenlnterval This is the listen interval of device.

7. txMaxPower This is the maximum transmit power of the Access Point 8. apRankDate This filed stores the access point rank calculation 9. apRank Access point rank

Table I

Field Field Name Description

1. macAddress This is MAC address of the Access Point 2. txSuccessFrameCount This is successfully transmitted frames by AP since last link metrics 3. txFailedFrameCount This is failed frames count by AP since last link metrics 4. txRetryCount This is number of tries for sending a packet whether successful or unsuccessful after one or more retransmission attempts. If for example, if a packet is transmitted once and it is successful, then txRetryCount will be 1. In brief, txRetryCount >=txFragmentCount + txFailedCount 5. txMultipleRetryCount This is number of frames successfully transmitted after more than one retransmission 6. avgRssi This is average rssi since previous link metrics.

7. avgSnr This is average snr since previous link metrics.

8. txRate This is the AP data rate.

9. timeDu ration This is time duration since previous link metrics.

Table 2

Table 2 contains data related to each unique AP known to the mobile device. Specific information related to the quality of the AP is stored, and one or more of these items of data can be used as the 01, or an algorithm may be used to combine these in some way to suit a particular situation. An example of an algorithm combining some of these fields follows later.

The data in the tables is updated periodically to ensure that an accurate and current record is kept for known APs.

The user may move away from the known AP and an attempt is then made to create a new connection to a known AP in the same way as has been described. Handover between the APs may be possible, or the user may have to manually manage the handover.

The mobile device 1 is therefore operable to always connect to a known AP having a known acceptable level of service based on a Quality Indicator (01).

As mentioned, the 01 can be based on one or more of the quantities known to the mobile device. In practice, the use of an algorithm combining more than one measure is found to be more useful, so in order to calculate 01 for the known APs in the vicinity of the mobile device, the APCM executes an algorithm which includes the following steps: 1. Fetch the list of APs in the vicinity of the device This is achieved by the mobile device fetching its current location from the GPS module 50. A local vicinity is then defined by adding a predefined distance, such as 200metres, to each of the x, y and z co-ordinates defining the current location. The x y and z co-ordinates are derived in a known way from the latitude, longitude and altitude co-ordinates provided by the GPS module 50. Adding the predefined distance to each of the x y and z co-ordinates yields a further co-ordinate set (xl, yl, zi). Any AP in the local database 40, which is located within the sphere defined by (x, y, z) and (xi, yl, zi) is considered to be in the vicinity of the mobile device.

2. Calculate average RSSI and average SNR for each AP in the device proximity.

This may be done as follows: Avg. RSSI = i/N (Sum of all the RSSI signals) Avg. SNR = 1/N (Sum of all the SNR signals) Further statistical analysis may be used to determine how far the signals are from the average: Standard Deviation (RSSl) = 1/ (N-i) (Sum of squares of each RSSI signal from mean value) Standard Deviation (SNR) = i/(N-1) (Sum of squares of each SNR from mean value) A higher standard deviation indicates that signals from the AP fluctuate a lot. This could be an indication of poor performance of the AP if the device position is not changing with respect to the original device position.

3. Get the list of APs which have avg.RSSI and avg. SNR more than RSSI threshold and SNR threshold. Threshold values are selected which give an acceptable level of performance.

4. Calculate failed and retransmission frames percentage per second for list of APs in the device proximity as determined in point 3.

An access point is reliable and provides good service qualities if failed and retransmission frames counts are minimum, and avg. RSSI and SNR are good. The user can expect a good service while making call over lP, video streaming or browsing using such an AP. The following formula will be used to calculate these values -Failed frame count (%) per sec = (Total failed frame count I Total frame sent) * 100 *(1/totaj period in sec) Failed retransmission frames count (%) per sec= (Total retransmission frame count I Total frame sent) * *(lltotal period in sec) 5. Select the AP which has min(Failed frames percentage) + min(Retransmission frames percentage) 6. If there is no AP satisfying point 5 above, then select instead the AP which has mm (Failed frames percentage + Retransmission frames percentage), which will be the next best possible AP in the current vicinity.

In step 1, in order to establish the location of the mobile device, data is requested from the GPS module 50. This is able to provide the location of the mobile device to a suitable level of accuracy. However, in some circumstances, it may not be possible for the GPS module to provide location data e.g. if there is not an unimpeded path to the appropriate number of satellites. If GPS data is not available, then the mobile device is operable to infer its location from other data sources. One possible alternative source is the ssid, MAC address or other identifier of nearby APs. Another possible alternative is to use known information about the routine of the user. For instance, the local date and time is known to the mobile device in a known way, either from the cellular network or a local timer. In the past, if the user has taken a mid-morning coffee in a basement coffee shop at or about a certain time, where GPS signals are not available, it may be reasonably inferred that he is in a known location and an attempt is made to access the AP associated with that known location. Over time, more information regarding a user's routine may be built up and used to infer location more accurately.

Another alternative is the cell identifier for the currently connected cellular BTS 2. A further alternative for inferring location is the present day and time.

Figure 2 shows a variation to the system shown in Figure 1. The mobile device I is identical, and it is operable to contact the cellular network 2 in the usual way, and to connect to APs in the way herein described. The difference lies in that a further database 45 is provided at a remote, central, location. The database 45 may be part of the cellular network 2 or it may be part of an Internet Service Provider's network. The database 45 is configured to store similar data to the local database 40, but on a much larger scale. Once a particular mobile device has assessed available APs, then the results of the assessment may be transmitted for storage by the remote database 45. The results may be transmitted, as shown in Figure 2, via the AP or the cellular network.

In this way, mobile devices which are not equipped with the ability to assess and rank possible local APs can be provided with information about which local AP may be the best one for them to connect to. The remote database also enables the providers of AP to assess the performance of their network and to undertake any remedial action for any APs which seem to offer consistently poor performance.

Figure 3 shows a flowchart setting out the operation of the embodiments described in a little more detail. The flowchart begins at S100. At 5110, a check is made to see if Wi-Fi is enabled, If not, then operation proceeds to STOP at S230. If Wi-Fi is enabled, then at S120, a check is made to see if the device is connected to an AP.

If it is connected to an AP, then at step S130. AP metrics are retrieved and calculations including determining average RSSl and average SNR are performed. The results of these are then stored in the local database 40.

If, on the other hand, it is determined at S120 that the mobile device is not connected to an AP, then S140 determines if the device's GPS module is able to supply current location information. If this data is available, then at step S160, the calculation determine which APs exist within a defined proximity of the current location, is performed to create a candidate list of possible APs.. If location information is not available from the GPS module, then a list of APs is retrieved from the remote server and this is used to update the local database 40.

At S170, a check is performed to determine whether any of the APs in the local database 40 is actually in the proximity of the device. If there are none, then the location timer is started at S180, the Wi-Fi chipset or transceiver is powered off at S200 and the operation stops at S230.

If the check at S170 reveals that there is at least one AP in the proximity of the movile device, then at S190, the Wi-Fi chipset or transceiver is powered on, and the AP having the maximum 01 is selected for connection. At S210, the selected AP is connected, and various metrics are fetched and used to update the local database 40. At S220, location timer and RSSI timer are started, the connection is maintained and the operation stops at S230.

Figure 4 shows a schematic representing the operation of the mobile device I according to an embodiment of the present invention travelling between different locations. At power on, the mobile device 1 is located at LOGO. No Wi-Fi access is required, so the Wi-Fi transceiver is disabled. On moving to the next location LOG 1, the user starts an application on the device 1 which requires Wi-Fi access to the internet. At LOGI, there are three possible Access Points APi, AP2 and AP3. Using the methods described herein, the mobile device selects the access point having the highest 01, calculated as previously described. It could be that APi has the highest signal strength and would be the AP most likely to be selected by prior art mobile devices, whereas AP2, having a lower signal strength, but a better 01, is selected by mobile device 1.

The user then leaves LOG1 and travels to LOG2, where three different APs are available: AP4, APS and AP6. Again, the AP having the highest 01 is selected.

After leaving LOG2, the user arrives at LOG3, which has been visited before and it is known that no APs are available and the Wi-Fi transceiver is disabled. In this way, battery power is preserved by making use of the fact that no APs are available.

Embodiments of the invention enable the mobile device to learn which access point in a particular location are better, during normal use and automates best AP selection and seamless connection based on location and access point selection algorithms, as herein described.

Furthermore, embodiments of the invention facilitate significant device power saving based on location and access point use.

Embodiments of the invention enable access point prioritization, based on usage metrics and automatic connection to highest priority access point if it's available in the proximity. This ensures better service quality from the device.

Embodiments of the the invention switch off Wi-Fi chipset or transceiver completely (e.g. by disabling low frequency clock, high frequency clock and transceiver) if there is no access point in the device reference database in the current location without user notice even though Wi-Fi state is enabled by the user. This saves a considerable amount of device battery power.

Embodiments of the invention don't allow beacon interval if there is no access point in the reference database in the device proximity. This will avoid automatic active or passive scanning by device. This saves a considerable amount of device battery power.

Location based power saving is based on used access points in the reference database.

This saves more power by switching on Wi-Fi chip set or transceiver only when device is in proximity of the user's most frequently used access points e.g. at home, in office, at café Embodiments have the option to synchronise with a remote database for fetching access points in case a device GPS fix is not available. Furthermore, access point information may be transmitted to the remote database to update it.

Embodiments of the present invention have a minimum impact on existing architecture and provide an easy update path for Wi-Fi enabled devices.

At least some elements discussed herein may be constructed, partially or wholly, using dedicated special-purpose hardware. Terms such as component', module' or unit' used herein may include, but are not limited to, a hardware device, such as a Field Programmable Gate Array (FPGA) or Application Specific Integrated Circuit (ASIC), which performs certain tasks.

At least some elements may be may be configured to reside on an addressable storage medium and be configured to execute on one or more processors. That is, the elements may be implemented in the form of a tangible computer-readable storage medium having recorded thereon instructions that are, in use, executed by a computer or other suitable device. The elements may include, by way of example, components such as software components, object-oriented software components, class components and task components, processes, functions, attributes, procedures, subroutines, segments of program code, drivers, firmware, microcode, databases, data structures, tables, arrays, and variables. The tangible medium may take any suitable form, but examples include solid-state memory devices (ROM, RAM, EPROM, EEPROM, etc.), optical discs (e.g. Compact Discs, DVDs, and others), magnetic discs, magnetic tapes and magneto-optic storage devices.

The example embodiments have been described with reference to the example components, modules and units discussed herein. Where appropriate, these functional elements may be combined into fewer elements or separated into additional elements. In some cases the elements are distributed over a plurality of separate computing devices that are coupled by a suitable communications network, including any suitable wired networks or Attention is directed to all papers and documents which are filed concurrently with or previous to this specification in connection with this application and which are open to public inspection with this specification, and the contents of all such papers and documents are incorporated herein by reference.

All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive.

Each feature disclosed in this specification (including any accompanying claims, abstract and drawings) may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features.

The invention is not restricted to the details of the foregoing embodiment(s). The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.

Claims

CLAIMS1. A method of operating a mobile device, said mobile device being operable to selectively connect to a wireless network, the method comprising the steps of: monitoring the location of the mobile device; determining if the location is a known location; 1 0 if the location is a known location, determining if there are known wireless network access points associated with the location; and if there are known wireless network access points associated with the location, selecting the best access point on the basis of a predetermined criterion, and enabling a wireless 1 5 network transceiver to initiate communication with the selected access point.
2. The method as claimed in claim 1 wherein if the location is a known location and there is no known access point associated with the location, then disabling the wireless network transceiver.
3. The method as claimed in claim 1 wherein if the location is an unknown location: enabling the wireless network transceiver to scan for wireless network access points in the vicinity; if wireless access points are detected, storing details relating thereto and initiating communication with the best one of the detected access points on the basis of the predetermined criterion.
4. The method as claimed in claim 1 wherein if the location is an unknown location: fetching information from a remote server relating to access points associated with the location; storing fetched information relating to the access points; enabling the wireless network transceiver and initiating communication with the best one of the access points on the basis of the predetermined criterion.
5. The method as claimed in claim 3 or 4 wherein if no access points are either detected or fetched from the server, then storing information relating to the absence of access points associated with the location and disabling the wireless network transceiver.
6. The method as claimed in any preceding claim wherein the predetermined criterion for selecting the best access point is is evaluated in advance.
7. The method as claimed in claim 6 wherein the predetermined criterion evaluates access points at a given location on the basis of one or more of: failed data frames; re-transmitted data frames; successful data frames; average RSSI; SNR; data rate; chipset compatibility; age of stored data relating to a particular access point; and current signal strength.
8. The method as claimed in any preceding claim wherein the default condition of the wireless transceiver is disabled.
9. The method as claimed in any preceding claim wherein the location of the mobile device is determined on the basis of GPS data.
10. The method as claimed in claim 3 wherein the step of enabling the wireless network transceiver to scan is commenced automatically or as a result of a user instruction.
11. A mobile device comprising a wireless network transceiver for communicating with a wireless network, and further comprising: a location determining unit, arranged to determine a present location of the mobile device; an access point selector unit, arranged to select the best wireless network access point from amongst a list of known access points associated with the present location, according to a predetermined criterion; and a controller, arranged to control the wireless network transceiver such that if there are no wireless network access points associated the present location then the wireless network transceiver is disabled or, alternatively, to initiate communication with the selected best
12. The mobile device of claim 11 wherein if the location determining unit determines that the present location is a previously unknown location, the access point selector unit is arranged to either scan for wireless network access points in the vicinity or to fetch information from a remote server relating to access points associated with the location.
13. The mobile device according to claim 11 or claim 12 wherein the controller is arranged to selectively remove the power supply to the wireless network transceiver to disable it.
14. The mobile device as claimed in any of claim 11 to 13, wherein the mobile device comprises a local data store for storing information related to one or more wireless network access points at a plurality of known locations.
15. A tangible computer readable recording medium having recorded thereon instructions which, when executed, cause a computer to perform a method according to one of claims 1-10.
16. A method of selecting an Access Point for connecting a mobile device to a wireless network, whereby the mobile device is operable to: identify, using a database, access points in its vicinity; calculate, using information stored in the database, a Quality Indicator for identified access points; connecting to the access point with the highest quality indicator.
17. A method as claimed in claim 16 wherein the step of calculating includes: calculating an average RSSI for each identified AP; calculating an average SNR for each identified AP; rejecting those of the identified APs which have average RSSI and SNR below a predefined threshold; calculating failed and retransmission frames percentage per second for the remaining APs; selecting the AP which has the minFailed frames percentage) + min(Retransmission frames percentage).