WO2014088394A2

WO2014088394A2 - A system and method for load balancing using virtual cell sizing in wireless networks

Info

Publication number: WO2014088394A2
Application number: PCT/MY2013/000214
Authority: WO
Inventors: Ting Kee Ngoh; Chieng Heng TZE; Kwong Kae HSIANG
Original assignee: Mimos Berhad
Priority date: 2012-12-03
Filing date: 2013-11-29
Publication date: 2014-06-12
Also published as: WO2014088394A3; MY172471A

Abstract

Load balancing of an access point (AP) in wireless networks is achieved through virtual cell sizing. The system comprising at least one wireless interface (210) adapted to associate and communicate with wireless users; at least one AP interface (230) adapted to communicate with neighbouring APs; at least one scanning interface (220) adapted to detect user stations (STAs) associated with said AP; at least one STAs detection module (SDM) (240) in communication with said at least one scanning interface (220) and said at least one AP interface (230), said SDM (240) being adapted to detect target STAs for potential offloading and communicate with SDMs of neighbouring APs; at least one AP loading monitor and decision module (ALDM) (250) in communication with said SDM (240) and said at least one wireless interface (210), said ALDM (250) being adapted to monitor the level of loading of said AP; at least one support rates controller (SRC) (260) in communication with said ALDM (250), said SRC (260) being adapted to control supported rates of said AP; and at least one beacon updater (BU) (280) in communication with said SRC (260), said BU (280) being adapted to update a support rates field in a beacon broadcast by said AP. The AP loading monitor and decision module (ALDM) (250) monitors the load of said AP and is adapted to determine whether to off- load excessive STAs to neighbouring APs by shutting down a supported rate, or to enable a supported rate when said AP is underloaded.

Description

A SYSTEM AND METHOD FOR LOAD BALANCING USING VIRTUAL CELL SIZING IN

WIRELESS NETWORKS

FIELD OF INVENTION

The present invention relates to a system and method for load balancing in wireless networks. In particular, the invention relates to such systems and methods in which users are removed from an access point (AP) by deactivating the lowest supported rate or modulation coding scheme of that AP and offloading users operating in that supported rate or modulation coding scheme to a neighbouring AP.

BACKGROUND ART

It is generally known that the distribution of wireless users in any predetermined area is normally not uniform. That is, wireless users tend to gather in specific areas, for any number of reasons, which causes uneven demand of capacity, for example some access points (APs) may be more congested than others.

In crowded environments, such as urban high streets, parks, conference halls, stadiums and so on, the capacity demand may be extremely high and the deployment of wireless APs is usually relatively dense to meet the capacity requirements. When the distribution of wireless users is non-uniform, some APs may be heavily loaded and other APs may be underutilised. However, due to dense AP deployment overlapping of coverage area often occurs and, therefore, offloading of the overloaded APs to balance load across the APs in the network is generally possible. Studies have suggested that in highly congested environments, a simple matrix such as number of client stations (STAs) per AP is still a good metric for load balancing.

United States Patent No. 7,715,353 discloses methods in which utilization of wireless APs is optimized by dynamically managing transmitted AP power levels of beacon packets to control wireless AP coverage, thereby permitting traffic congestion at one wireless AP to be reduced and shifted to other wireless APs. In this patent, AP coverage management is provided by a centralized mechanism that employs various interpretations and/or measurements of client received power to handle dynamic changes in client workloads. The control does not require protocol changes to clients that utilize a wireless AP and can also incorporate hand-off costs and/or manufacturer specified power level constraints. It is suggested that these techniques can be employed in existing wireless LANs without impacting clients and that various instances are employable with continuous power and/or discrete power based wireless APs, providing a non-client impacted means to increase throughput and/or load balance. Generally speaking, this is a method of centralised control in which beacon power is the determining factor in balancing demand by limiting the number of associated users.

United States Patent Application Publication No. 2011/0075556 discloses systems and methods for dynamic load balancing in a wireless network, such as a wireless local area network (WLAN) and the like. Specifically, this publication discloses systems and methods that periodically provide dynamic load balancing of mobile devices. This may include determining an optimum load and instructing wireless access devices that are overloaded to disassociate some mobile devices based upon predefined criteria. This disassociation is performed in a manner to minimise disruption by dissociating mobile devices with low usage, with close proximity to underutilized wireless access devices, and mobile devices not currently operating critical applications, such as voice.

United States Patent No. 7,162,250 describes a load balancing system and methodology for packet-based wireless cellular networks, whereby wireless access points are dynamically reconfigured by altering their transmission power level to modify their area of coverage. The modification function is based on the localized traffic load or congestion at each individual access point, or the collective load experience by groups of access points. The modification to the cellular layout is used as an implicit load balancing technique. When an overloaded access point reduces its coverage area, it forces some wireless client devices that were earlier within its footprint, but no longer within it coverage area, to attach to alternative access points. Similarly, when an under-loaded access increases its coverage area, it provides an opportunity to wireless devices, which were earlier outside its footprint, but now within the expanded coverage area, to switch attachment to this access point. By changing the access point to which a wireless device attaches, the load- levels on the individual access points are indirectly changed. As such, known methods may involve a reduction in radio transmit power to shrink coverage area and, therefore, disconnection of excessive users for a particular AP. A drawback of this method is that reducing the power will weaken the overall wireless link between the serving AP and STAs associated with it. A weaker wireless link due to lower received signal power at the STA receivers will cause reductions in speed or increased packet error rates. Also, although STAs are offloaded to other Aps, the quality of the link and spectrum efficiency of the whole AP drops. Eventually, STAs enjoy less capacity than would otherwise be the case. Other options involve reducing beacon power from serving APs only, while maintaining the transmit power for all data transmissions. The beacon is used as a signal to show the presence of an AP. Reducing the beacon signal power means reducing the coverage area and number of users that can hear the AP. Although reducing the beacon power and maintaining the data transmit power maintains the downlink data rate, uplink users may use the beacon to judge the uplink channel which may mislead the user into using a lower uplink data rate.

The subject matter claimed herein is not limited to embodiments that solve any disadvantages or that operate only in environments such as those described above. Rather, this background is only provided to illustrate one exemplary technology area where some embodiments described herein may be practice.

SUMMARY OF INVENTION

One aspect of the present invention provides a system (200) for load balancing of an access point (AP) in wireless networks using virtual cell sizing. The system comprising at least one wireless interface (210) adapted to associate and communicate with wireless users; at least one AP interface (230) adapted to communicate with neighbouring APs; at least one scanning interface (220) adapted to detect user stations (STAs) associated with said AP; at least one STAs detection module (SDM) (240) in communication with said at least one scanning interface (220) and said at least one AP interface (230), said SDM (240) being adapted to detect target STAs for potential offloading and communicate with SDMs of neighbouring APs; at least one AP loading monitor and decision module (ALDM) (250) in communication with said SDM (240) and said at least one wireless interface (210), said ALDM (250) being adapted to monitor the level of loading of said AP; at least one support rates controller (SRC) (260) in communication with said ALDM (250), said SRC (260) being adapted to control supported rates of said AP; and at least one beacon updater (BU) (280) in communication with said SRC (260), said BU (280) being adapted to update a support rates field in a beacon broadcast by said AP. The at least one AP loading monitor and decision module (ALDM) (250) monitors the load of said AP and is adapted to determine whether to off-load excessive STAs to neighbouring APs by shutting down a supported rate when the said AP is overloaded, or to enable a supported rate when said AP is underloaded.

In another aspect the invention provides a system wherein said scanning interface (220) operates in monitor mode and does not provide access to STAs associated with said AP. In a further aspect the invention provides a system wherein said SRC (260) having means for controlling supported rates of the AP (200) based on decisions made by the ALDM (250); and controlling said supported rates with reference to a supported rate table (270). In yet another aspect the invention provides a system wherein said SDM (240) having means for listing said STAs associated with said AP, based on said at least one supported rate (401); sending an STA connectivity checking request (SC_REQ) to neighbouring SDMs associated with neighbouring APs (402); and sending said list of STAs to said neighbouring SDMs (403); whereby, on receiving said SC_REQ, said neighbouring SDMs: initiating a scanning interface, scan on all available channels and listen to packets sent by said STAs on said list of STAs for a predefined duration (404); and sending results of said scanning to said SDM (240) associated with said AP (405); whereby the number or percentage of STAs with alternative connections within said wireless network (406) is calculated.

In still another aspect the invention provides a system, wherein said SDM (240) further having means for determining the number of STAs with no alternative connection by subtracting the number of STAs with at least one alternative connection,

from the number of said STAs falling within said at least one supported rate, N_Targ_et_Mcs (501).

In a further aspect the invention provides a system, wherein said SDM (240) further having means for determining the percentage of STAs with no alternative connection, N_Targe_LMcs - N_Aitemative_conneceon. over the number of said STAs falling within said at least one supported rate, N_Target_ucs (502), and compares this with a threshold value to determine whether said at least one supported rate should be deactivated.

In a further aspect the invention provides a method (300) for load balancing using virtual cell sizing in wireless networks. The method comprising steps of determining whether an access point (AP) within the wireless network is overloaded (302); checking for the availability of total modulation and coding schemes (MCS) and supported rates currently active on overloaded AP based on a support rates control table wherein if there is only one active MCS, AP cannot switch it off to offload STAs and therefore the said program ends(304); identifying user stations (STAs) associated with the AP falling within the at least one supported rate to determine whether alternative MCS from other AP(s) are available (304a). The method further comprises sending the identity of the STAs falling within the at least one supported rate to neighbouring APs within the wireless network to identify alternative connectivity for the STAs by the neighbouring APs (305); receiving information on the alternative connectivity for the STAs from neighbouring APs and deciding whether to deactivate the at least one supported rate (306); if the decision is in the positive, deactivating the at least one supported rate within the AP (307); updating the support rates control table (310); and broadcasting an updated beacon across the wireless network (311).

In another aspect the invention provides a method wherein determining whether an access point (AP) within said wireless network is overloaded (302) further comprises the following steps when said AP is not overloaded. If the AP is not overloaded, determining whether the AP is underloaded (303); checking the support rates control table for any inactive supported rate if the AP is underloaded (308); activating a supported rate that is one order lower than the lowest active supported rate if the AP is underloaded (309); updating the support rates control table (310); and broadcasting an updated beacon across the wireless network (311).

In a further aspect the invention provides a method (300) wherein the step of sending the identity of the STAs to neighbouring APs within the wireless network (305) comprises listing the STAs using an STAs detection module (SDM) associated with the AP, based on the at least one supported rate (401); sending an STA connectivity checking request (SC_REQ) to neighbouring SDMs associated with the neighbouring APs (402);sending the list of STAs to the neighbouring SDMs (403);on receiving the SC_REQ, the neighbouring SDMs initiating a scanning interface, scanning on all available channels and listening to packets sent by the STAs on the list of STAs for a predefined duration (404);the neighbouring SDMs sending results of the scanning to the SDM associated with the AP (405); and calculating the number or percentage of STAs with alternative connections within the wireless network (406). In still another aspect the invention provides a method (300) wherein the step of receiving information on the alternative connectivity for the STAs from neighbouring APs and deciding whether to deactivate the at least one supported rate (306) comprises determining the number of STAs with no alternative connection by subtracting the number of STAs with at least one alternative connection, N_Memative_connectbn, from the number of the STAs falling within the at least one supported rate, N_Target_Mcs (501); and if the difference is above a threshold value, ending the method; or if the difference is less than or equal to the threshold value, determining the percentage of STAs with no alternative connection, NrargetMcs -NAHem_ative_connection. over the number of the STAs falling within the at least one supported rate, N_Target__Mcs (502), and if the percentage is less than or equal to a threshold value continuing with the method, or if the percentage is greater than the threshold value ending the method.

The present invention consists of features and a combination of parts hereinafter fully described and illustrated in the accompanying drawings, it being understood that various changes in the details may be made without departing from the scope of the invention or sacrificing any of the advantages of the present invention.

BRIEF DESCRIPTION OF ACCOMPANYING DRAWINGS

To further clarify various aspects of some embodiments of the present invention, a more particular description of the invention will be rendered by references to specific embodiments thereof, which are illustrated in the appended drawings. It is appreciated that these drawings depict only typical embodiments of the invention and are therefore not to be considered limiting of its scope. The invention will be described and explained with additional specificity and detail through the accompanying drawings in which:

FIGS. 1A to 1C illustrate the concept of AP offloading in a wireless network with overlapping coverage.

FIG. 2 illustrates an access point (AP) of an embodiment of the invention, including new modules to support load balancing. FIG. 3 illustrates a general load balancing flowchart of an embodiment of the invention.

FIG. 4 illustrates a flowchart describing the function of the STAs Detection Module.

FIG. 5 illustrates a decision making flowchart for deciding whether to offload a user from an AP.

Table 1 : Supported Rates Control Table. Table 2: Modulation dependent parameters.

Table 3: Beacon frame body.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention provides a system and method for load balancing in wireless networks. In particular, the invention relates to such systems and methods in which users are removed from an access point (AP) by deactivating the lowest supported rate or modulation and coding scheme of that AP and offloading users operating in that supported rate or modulation and coding scheme to a neighbouring AP.

Hereinafter, this specification will describe the present invention according to the preferred embodiments. It is to be understood that limiting the description to the preferred embodiments of the invention is merely to facilitate discussion of the present invention and it is envisioned without departing from the scope of the appended claims.

Figures 1A to 1C exemplify a scenario where uneven distribution of network load can occur. In Figures 1A to 1C, STAs are represented by smaller dots (dark and light) and APs are represented by larger dots. Coverage of each AP is represented by the circles around it. Multiple circles represent the multi-rate support by the wireless technology, where users residing in the inner circles will have higher connection speed as compared to users in the outer circles.

Referring to Figure 1 A, there are four APs, namely AP1 , AP2, AP3 and AP4. Each AP has several STAs connected to it as shown by the figures in the brackets. The colour of the STA shows whether they are covered by one AP (dark) or more than one AP (light). Since all the light coloured STAs are closer to AP1 , they are naturally connected to this AP given the higher receiving signal from AP1. As a result, AP1 has the most number of STAs associated with it, 10 in total, as compared to 2 STAs for each of the other APs. Assuming all of the STAs are generating a significant amount of traffic, AP1 will be overloaded while the other APs will be comparatively lightly loaded. Figure 1 B identifies that the light coloured STAs covered by multiple APs are generally located in the outer two circles of AP1. This implies that, those STAs are only capable of operating in the lowest two supported data rates or modulation and coding schemes (MCS). As used herein, the terms "supported rates" and "MCS" may be used interchangeably. If the lowest two supported rates are disabled, as shown in Figure 1C, those STAs can no longer send their traffic to AP1 and have no choice but to connect to the other available APs. As a result, the number of STAs associated with AP1 is reduced from 10 to 6, and the associated traffic is likewise reduced, and are offloaded to other neighbouring APs.

The concept of offloading an AP by deactivating lower support rate(s) not only increases STA capacity by reducing the number of STAs connected to AP1 , it also ensures the use of higher supported rates, which is more spectrum efficient as shown in Figure 1 C. Therefore, STAs operating on higher supported rates enjoy more capacity as they will not be affected by associated slower STAs.

Figure 2 shows an access point (AP) (200) with modules that support load balancing functionality. In particular, the AP (200) includes an interface(s) to STAs (210) that is the interface to end users and which provides access to the users. The AP (200) may include one or more than one interface to STAs (210). An STA scanning interface (220) is used to scan for the existence of target STA(s) within the coverage of the AP. It operates in monitor mode and does not provide access to STAs. An Interface to neighbour AP (230) provides an interface for the AP to communicate with neighbouring APs. This may take the form of any wired or wireless technology.

An STAs detection module (240) sits between the STA scanning interface (220), the interface to neighbour AP and an AP loading monitor and decision module (ALDM) (250). The STA detection module (240) handles communications between APs when alternative connectivity of certain STAs to nearby APs needs to be confirmed. This module also handles detection of target STA(s) when a request is received from a neighbouring AP. The ALDM (250) monitors the load of the AP and decides whether to off-load excessive STAs to other APs by shutting down a supported rate, or to enable a supported rate when the AP is under loaded.

The AP (200) also includes a supported rates controller (SRC) (260) that controls the supported rates of the AP (200) based on decisions made by the ALDM (250), generally by referring to a supported rate table (270). Finally, a beacon updater (BU) (280) updates beacon field based on the instructions received from the SRC (260).

Referring to Figure 3, a general load balancing process (300) flow chart is provided. The process (300) is initiated (301) during boot up or through other means whenever load balancing process is required. Following initiation (301), the process involves evaluation (302) of whether the AP is overloaded by comparing AP's load with a threshold. The overloaded threshold can be a predefined value or may be a calculated value based on the operating environment. One example of methodology that may be applicable, although not limiting on the invention in any way, is defined in section 7.3.2.28 of IEEE 802.11- 2007, the 2007 IEEE Standard for Information technology - Telecommunications and information exchange between systems - Local and metropolitan area networks - Specific requirements - Part 11 : Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) Specifications.

If the AP is not overloaded the process involves evaluation (303) of whether the AP is under-loaded by comparing the AP's load with a threshold. The under-loaded threshold can be a predefined value or may be a calculated value based on the operating environment. If the AP is under-loaded, the process includes checking (308) if there are any more supported rate from supported rate control table (see Table 1 ), which is inactive. The process is ended (312) if there are no more inactive supported rates. Otherwise, the SRC activates (309) a supported rate that is one order lower than the lowest supported rate that is active. If it is determined that the AP is overloaded during evaluation (302), the process includes checking (304) whether there is more than one active supported rate available. If this is not the case, the process is ended (312). Otherwise, the process includes checking (305) whether the user(s) that currently operate at the lowest data rate can find at least one alternative connection. A more detailed discussion of this operation is provided with reference to Figure 3. The process then involves determining (306) whether to offload the user(s) from the AP. A more detailed discussion of this operation is provided with reference to Figure 4. The SRC then stops or deactivates (307) the lowest data rate among the active data rates for the AP. Once this process is complete, the beacon updater (BU) updates the supported rates field in the beacon (310). The AP then broadcasts the updated beacon (311) as usual.

Figure 4 provides a more detailed description of the step of checking (305) whether the user(s) that currently operate at the lowest data rate can find at least one alternative connection, as discussed above.

Referring to Figure 4, the STAs detection module (SDM) residing in the AP lists all STAs operating in the lowest active supported rate (401). The SDM then sends an STAs connectivity checking request (SC_Req) to neighbouring APs (402). Following this step, the SDM sends a list of the STAs media access control (MAC) addresses to neighbouring APs (403). Upon receiving the SC_Req and STAs list from the requester SDM, the receiving SDM initiates the STA scanning interface to scan all available channels and listen to packets sent by STAs on the list for a predefined period of time (404). Neighbouring APs can be detected by using the method defined in standard IEEE 802.11k-2008 - Amendment 1 : Radio Resource Measurement of Wireless LANs, although the invention is not so limited and other options may be equally applicable. STAs scanning can be performed using the method as shown in Sang-Hee Park et al, Selective Channel Scanning for Fast Handoff in Wireless LAN Using Neighbor Graph, PERSONAL WIRELESS COMMUNICATIONS, Lecture Notes in Computer Science, 2004, Volume 3260/2004, 629.

Once the STAs detecting task is completed, the receiving SDM sends the report to the requester SDM (405). The requesting SDM receives the reports from neighbouring SDM(s) (406) and the process returns to that illustrated in the general flow chart provided in Figure 3.

With reference to Figure 5, given that the number of user in the target MCS zone is NrargeLMcs, the number of user with alternative connection,

can be obtained from the report received from checking step (305) referred to in Figure 3. Subsequently, the number of users with no alternative can be calculated (501) as N_Target_Mcs - N_Mematjve_connec6on. This value must be less than a predefined number X, which is a value that can be set by network operator to achieve desired performance. If the condition is not met, the process returns to step (312) of Figure 3, which is the end of process. If the condition is met, the process proceeds to step (502).

In step (502), the process involves calculating the percentage of STAs with no alternative connection, N_Target_Mcs - N_Mernative_connect n. over the total number of user in the target CS zone, N_Target_Mcs. If the percentage is less than certain predefined value, V, the SRC then stops or deactivates (307) the lowest data rate among the active data rates for the AP, otherwise the process is ended (312). Y is a value that can be set by network operator to achieve desired performance.

The load balancing process described above only describes one cycle of channel selection for the AP. In practice, the STAs may enter and leave the wireless network as needed. Therefore, the load balancing cycle has to be dynamic enough to cope with the channel changes. Periodic triggering of the load balancing process may be achieved by setting a timer in the AP. Alternatively; the AP may monitor the loading condition and trigger the process on a needs basis. In this embodiment, the AP decides when to trigger the load balancing process. The implementation of the triggering process may involve a suitable triggering algorithm, besides the aforementioned suggestions and the invention is not particularly limited in this regard.

For reference, Tables 2 and 3 provide information on modulation dependent parameters and beacon frame body respectively. Within the beacon, a supported rate contained in the BSSBasicRateSet parameter is encoded as an octet with the MSB (bit 7) set to 1 , and bits 6 through 0 are set to the data rates not contained in the BSSBasicRateSet parameter and encoded with the MSB set to 0, and bits 6 through 0 are set to the appropriate value.

Unless the context requires otherwise or specifically stated to the contrary, integers, steps or elements of the invention recited herein as singular integers, steps or elements clearly encompass both singular and plural forms of the recited integers, steps or elements.

Throughout this specification, unless the context requires otherwise, the word "comprise", or variations such as "comprises" or "comprising", will be understood to imply the inclusion of a stated step or element or integer or group of steps or elements or integers, but not the exclusion of any other step or element or integer or group of steps, elements or integers. Thus, in the context of this specification, the term "comprising" is used in an inclusive sense and thus should be understood as meaning "including principally, but not necessarily solely".

It will be appreciated that the foregoing description has been given by way of illustrative example of the invention and that all such modifications and variations thereto as would be apparent to persons of skill in the art are deemed to fall within the broad scope and ambit of the invention as herein set forth.

Claims

1. A system (200) for load balancing of an access point (AP) in wireless networks using virtual cell sizing, the system comprising:

at least one wireless interface (210) adapted to associate and communicate with wireless users;

at least one AP interface (230) adapted to communicate with neighbouring APs;

at least one scanning interface (220) adapted to detect user stations (STAs) associated with said AP;

at least one STAs detection module (SDM) (240) in communication with said at least one scanning interface (220) and said at least one AP interface (230), said SDM (240) being adapted to detect target STAs for potential offloading and communicate with SDMs of neighbouring APs; at least one AP loading monitor and decision module (ALDM) (250) in communication with said SDM (240) and said at least one wireless interface (210), said ALDM (250) being adapted to monitor the level of loading of said AP;

at least one support rates controller (SRC) (260) in communication with said ALDM (250), said SRC (260) being adapted to control supported rates of said AP; and

at least one beacon updater (BU) (280) in communication with said SRC (260), said BU (280) being adapted to update a support rates field in a beacon broadcast by said AP

characterized in that

the at least one AP loading monitor and decision module (ALDM) (250) monitors the load of said AP and is adapted to determine whether to offload excessive STAs to neighbouring APs by shutting down a supported rate, or to enable a supported rate when said AP is underloaded. A system according to claim 1 , wherein said scanning interface (220) operates in monitor mode and does not provide access to STAs associated with said AP.

A system according to claiml , wherein said SRC (260) further having means for: controlling supported rates of the AP (200) based on decisions made by the ALDM (250); and

controlling said supported rates with reference to a supported rate table (270). 4. A system according to claim 1 , wherein said SDM (240) further having means for:

listing said STAs associated with said AP, based on said at least one supported rate (401);

sending an STA connectivity checking request (SC_REQ) to neighbouring SDMs associated with neighbouring APs (402); and

sending said list of STAs to said neighbouring SDMs (403); whereby, on receiving said SC_REQ, said neighbouring SDMs: initiating a scanning interface, scan on all available channels and listen to packets sent by said STAs on said list of STAs for a predefined duration

(404) ; and

sending results of said scanning to said SDM (240) associated with said AP

(405) ;

whereby the number or percentage of STAs with alternative connections within said wireless network (406) is calculated. 5. A system according to claim 4, wherein said SDM (240) further having means for determining the number of STAs with no alternative connection by subtracting the number of STAs with at least one alternative connection, N_Memative_connection, from the number of said STAs falling within said at least one supported rate, N_Target_Mcs (501).

6. A system according to claim 4, wherein, said SDM (240) further having means for determining the percentage of STAs with no alternative connection, N_TargeLMcs - NAitemativejconnection, over the number of said STAs falling within said at least one supported rate, N_Target_Mcs (502), and compares this with a threshold value to determine whether said at least one supported rate should be deactivated.

7. A method (300) for load balancing using virtual cell sizing in wireless networks, the method comprising steps of:

determining whether an access point (AP) within said wireless network is overloaded (302);

checking for the availability of total modulation and coding schemes (MCS) and supported rates currently active on overloaded AP based on a support rates control table wherein if there is only one active MCS, AP cannot switch it off to offload STAs and therefore the program ends (304); and identifying user stations (STAs) associated with said AP falling within said at least one supported rate (304a)

characterised in that

identifying user stations (STAs) associated with said AP falling within said at least one supported rate to determine whether alternative MCS from other APs are available (304a) further

comprises steps of:

sending the identity of said STAs falling within said at least one supported rate to neighbouring APs within

said wireless network to identify alternative connectivity for said STAs by said neighbouring APs (305);

receiving information on said alternative connectivity for said STAs from neighbouring APs and deciding whether to deactivate said at least one supported rate (306);

if said decision is in the positive, deactivating said at least one supported rate within said AP (307);

updating said support rates control table (310); and broadcasting an updated beacon across said wireless network (311).

8. A method according to claim 7, wherein determining whether an access point (AP) within said wireless network is overloaded (302) further comprises the following steps when said AP is not overloaded:

determining whether said AP is underloaded (303);

checking said support rates control table for any inactive supported rate if said AP is underloaded (308);

activating a supported rate that is one order lower than the lowest active supported rate if said AP is underloaded (309);

updating said support rates control table (310); and

broadcasting an updated beacon across said wireless network (311).

9. A method (300) according to claim 7, wherein the step of sending the identity of said STAs to neighbouring APs within said wireless network (305) further comprises steps of:

listing said STAs using an STAs detection module (SDM) associated with said AP, based on said at least one supported rate (401);

sending an STA connectivity checking request (SC_REQ) to neighbouring

SDMs associated with said neighbouring APs (402);

sending said list of STAs to said neighbouring SDMs (403); on receiving said SC_REQ, said neighbouring SDMs initiating a scanning interface, scanning on all available channels and listening to packets sent by said STAs on said list of STAs for a predefined duration (404);

said neighbouring SDMs sending results of said scanning to said SDM associated with said AP (405); and

calculating the number or percentage of STAs with alternative connections within said wireless network (406).

10. A method (300) according to claim 7 , wherein said step of receiving information on said alternative connectivity for said STAs from neighbouring APs and deciding whether to deactivate said at least one supported rate (306) further comprises steps of:

determining the number of STAs with no alternative connection by subtracting the number of STAs with at least one alternative connection, NAHemati_Ve_connection. from the number of said STAs falling within said at least one supported rate, N_Target_Mcs (501); and

if the difference is above a threshold value, ending the method; or if the difference is less than or equal to said threshold value, determining the percentage of STAs with no alternative connection, Λ/_{Γ3 β},__Μ05 -

NAHemative_connection, over the number of said STAs falling within said at least one supported rate,

(502), and if the percentage is less than or equal to a threshold value continuing with the method, or if the percentage is greater than said threshold value ending the method.