Patent Application
20080144588
Wireless local area networks (WLAN) may include a basic service set (BSS). The BSS may include an access point (AP) and one or more stations (ST). The stations of the BSS may also be referred as nodes. An infrastructure WLAN, may include two or more APs. An AP of the two or more APs may establish one or more BSSs and may serve each BSS with the same priority. According to a standard issued by an Institute of Electrical & Electronics Engineers (IEEE), e.g. IEEE P802.11-REVma/D5.0, the BSS is identified by a Service Set Identifier (SSID) and a BSS Identifier (BSSID). For example the AP may send a beacon with two SSIDs, an Office WLAN identifier and a Guest WLAN identifier. The two or more BSSs of the infrastructure WLAN are provided with the same priority to the different services. Thus, the services may interfere each other.
The subject matter regarded as the invention is particularly pointed out and distinctly claimed in the concluding portion of the specification. The invention, however, both as to organization and method of operation, together with objects, features and advantages thereof, may best be understood by reference to the following detailed description when read with the accompanied drawings in which:
It will be appreciated that for simplicity and clarity of illustration, elements shown in the figures have not necessarily been drawn to scale. For example, the dimensions of some of the elements may be exaggerated relative to other elements for clarity. Further, where considered appropriate, reference numerals may be repeated among the figures to indicate corresponding or analogous elements.
In the following detailed description, numerous specific details are set forth in order to provide a thorough understanding of the invention. However it will be understood by those of ordinary skill in the art that the present invention may be practiced without these specific details. In other instances, well-known methods, procedures, components and circuits have not been described in detail so as not to obscure the present invention.
Some portions of the detailed description, which follow, are presented in terms of algorithms and symbolic representations of operations on data bits or binary digital signals within a computer memory. These algorithmic descriptions and representations may be the techniques used by those skilled in the data processing arts to convey the substance of their work to others skilled in the art.
Unless specifically stated otherwise, as apparent from the following discussions, it is appreciated that throughout the specification discussions utilizing terms such as “processing,” “computing,” “calculating,” “determining,” or the like, refer to the action and/or processes of a computer or computing system, or similar electronic computing device, that manipulate and/or transform data represented as physical, such as electronic, quantities within the computing system's registers and/or memories into other data similarly represented as physical quantities within the computing system's memories, registers or other such information storage, or transmission devices.
It should be understood that the present invention may be used in a variety of applications. Although the present invention is not limited in this respect, the circuits and techniques disclosed herein may be used in many apparatuses such as stations of a radio system. Stations intended to be included within the scope of the present invention include, by way of example only, wireless local area network (WLAN) stations, two-way radio stations, digital system stations, analog system stations, cellular radiotelephone stations, and the like.
Types of WLAN stations intended to be within the scope of the present invention include, although are not limited to, mobile stations, access points, stations for receiving and transmitting spread spectrum signals such as, for example, Frequency Hopping Spread Spectrum (FHSS), Direct Sequence Spread Spectrum (DSSS), Complementary Code Keying (CCK), Orthogonal Frequency-Division Multiplexing (OFDM) and the like.
Turning first to
According to some embodiments of the present invention, an allocation of different priorities to BSSs of WLAN 100 may be done by assigning different parameters to BSSs 120 and 140 based on IEEE P802.11-REVma/D5.0 standard. More specifically, Enhanced Distributed Channel Access (EDCA) parameters may be assigned to BSSs 120 and 140, if desired.
According to IEEE P802.11-REVma/D5.0 standard, EDCA parameters may include Element ID, Length, Quality of Service (QoS) information and access category (AC) parameters for Best Effort (AC_BE), Background (AC_BK), Video (AC_VI) and Voice (AC_VO). The AC parameters may include, a contention window minimum and maximum length (e.g., ECWmin and ECWmax) and a transmit opportunity limitation (e.g., TXOPLimit). Stations of BSS 120 and/or BSS 140 may gain access to WLAN 100 according to the contention window parameters and TXOP parameter, if desired.
According to one exemplary embodiment of the invention, setting different priority to BSS 120 and/or BSS 140 may be done by assign a different set of EDCA parameters to BSS 120 and/or BSS 140, respectively. According to other embodiments of the present invention, the assignment of different priorities to BSS 120 and 140 may be done by assign different ECWmin, and TXOP Limit values to BSSs 120 and 140 as is shown by table 1 below.
For example, the ECWmin is a value which represents the minimum size of the contention window for drawing the backoff time. The lower the value, the higher the priority. The TXOP Limit is a value used after the media access has been gained and depicts how long the station may continue of transmitting. The larger the value of TXOP Limit, the higher the priority. According to table 1, in order to set the highest priority to the Secure Office BSS (e.g, BSS 120) the ECWmin may be set to a low value and TXOPLimit may be set to a high value. In non-secure guest BSS (e.g., BSS 140) the ECWmin may be set to a high value and TXOPLimit may be set to a low value, although the scope of the present invention is not limited to this example.
Turning to
Transceiver 220 may transmit through an antenna 250, a beacon with the set of parameters in order to set different priorities to the different stations of the different BSSs. Antenna 250 may include a dipole antenna, a Yagi antenna, an antenna array, two or more antennas or the like. It should be understood that the described blocks and/or components of AP 200 may be implemented by hardware, by software and/or by any combination of hardware and software.
Turning to
According to one embodiment of the invention MAC 210 may set the priorities to first and second services provided by the first and second BSSs, respectively. MAC 210 may set the priorities by setting a first contention window value based on the first priority of the first service (text block 320) and a second contention window value based on the second priority of second service (text block 330). In addition, MAC 210 may set the priorities to first and second BSSs by setting a first transmit opportunity value base on the priority of the first service (text block 340) and setting a second transmit opportunity value base on the priority of the second service (text block 350).
While certain features of the invention have been illustrated and described herein, many modifications, substitutions, changes, and equivalents will now occur to those skilled in the art. It is, therefore, to be understood that the appended claims are intended to cover all such modifications and changes as fall within the true spirit of the invention.
