EP1810453A1

EP1810453A1 - A wlan station and a method of operating the station in infrastructure mode and in independent (ad-hoc) mode simultaneously.

Info

Publication number: EP1810453A1
Application number: EP05803619A
Authority: EP
Inventors: Örjan FRITZ; Per Konradsson
Original assignee: Nanoradio AB
Current assignee: Nanoradio AB
Priority date: 2004-11-12
Filing date: 2005-11-14
Publication date: 2007-07-25
Also published as: EP1810453A4; KR20070098802A; JP2008520162A; WO2006052214A1

Abstract

The present invention relates to WLAN station, or terminal, and a method for operating a WLAN (Wireless Local Area Network) station/terminal in different modes, said WLAN terminal is capable of operating in one infrastructure mode or in a second independent mode, mutually exclusive. The invented WLAN terminal is possible to set in a mixed mode by means of a mixed mode means for running the WLAN terminal in the infrastructure and independent modes simultaneously.

Description

A WLAN station and a method of operating the station in infrastructure mode and in independent (ad-hoc) mode simultaneously.

TECHNICAL FIELD

The present invention relates to Wireless Local Area Network, WLAN.

BACKGROUND OF THE INVENTION

Today the connection between a WLAN terminal and a WLAN peripheral device is established via the Access Point of a communication network. This is because the IEEE std 802.11 standard states that a device is either operating in Infrastructure mode (i.e. associated with an Access Point) or it is operating in Independent mode (i.e. direct connection between terminals without a central Access Point). Said prior art is further discussed in connection to figures Ia and Ib.

This standard requirement suffers from a number of drawbacks which will be further discussed below.

From the problem definition clause, it is given that the terminal needs to be connected in Infrastructure mode, as it needs access to the LAN.

The properties of the connection between the terminal and the peripheral are such that an Independent relation is most effective and practical.

A connection between two WLAN stations via an Access Point means that every packet needs to be transmitted over the air interface twice (from terminal 1 to AP and then from AP to terminal 2), while in Independent mode, each packet is transmitted DIRECTLY from station 1 to station 2. This means ineffective utilization of available bandwidth. If the connection between the terminal and the peripheral device where to done via the Access Point, the connection procedure would be quite complicated. Something like the following would be necessary (assuming the terminal is already associated with the Access Point):

1. The terminal leaves the Infrastructure association with the AP.

2. The terminal establishes an Independent association with the peripheral device.

3. Via an upper (proprietary) protocol, the terminal asks the peripheral device to leave the Independent association and instead associate with the Infrastructure network.

4. The peripheral device leaves the Independent network and associates with the Infrastructure network.

5. The terminal leaves the Independent network and re-establishes the association with the Infrastructure network.

The terminal and the peripheral device are ready to communicate via the Access Point.

It is unrealistic to require the presence of an Access Point every time the terminal needs to be connected to the peripheral device.

The object of this invention is to overcome said drawbacks and problems, and which provides an alternative solution of the suggested communication standard.

BRIEF DESCRIPTION OF THE INVENTION

The solution to the problem could generally be described as a logical split of the terminal unit into two logical units, where unit 1 operates in Infrastructure mode while unit 2 have an Independent association with the peripheral device and these two units are sometimes operating simultaneously by means of a mixed mode means for combining the two other mode and units. In more detail, the invented WLAN terminal comprises one state- machine intended for controlling the WLAN terminal in the Infrastructure mode, a second state-machine for controlling the WLAN terminal in the Independent mode, and mixed mode means for running the first and second state-machines in a mixed mode, wherein the WLAN terminal is capable of transferring data information in the infrastructure and independent modes simultaneously.

Different embodiments of the present invention are described in the description and the independent claims.

The invention also relates to a method for operating a WLAN (Wireless Local Area Network) terminal in different modes, said WLAN terminal is capable of operating in one infrastructure mode or in a second independent mode, mutually exclusive, characterized by the step of setting the WLAN terminal in a mixed mode by means of a mixed mode means for running the WLAN terminal in the infrastructure and independent modes simultaneously.

The present invention also relates to a computer program and a computer program product.

The disadvantages stated above are removed.

With the proposed solution (assuming the terminal is already associated with the Access Point), what instead happens is: - The terminal establishes an Independent relation with the peripheral device. The terminal and the peripheral device will have the possibility to communicate directly without the intermediate Access Point. As the peripheral device need only support Independent operation mode, and thus the implementation may be more compact with smaller memory footprint.

The crypto key management is simplified as the peripheral device otherwise would need to be provided with keys for the Infrastructure connection (possibly different keys for each different Access Point).

The proposed invention is compliant with the 802.11 standard. There is a proposed amendment by the IEEE organization (802.1 Ie) that addresses the same problem with a different solution (Direct Links) . The strength of the proposed invention is still that the connection between the terminal and the peripheral device does not require the presence of an Access Point that comply with the 802. l ie amendment of Direct Links.

BRIEF DESCRIPTION OF THE DRAWINGS Figure Ia and Ib are schematic block diagrams illustrating a communication network, a peripheral device and a prior art WLAN terminal operating according to the IEEE standard 802.11.

Figure 2 is a schematic block diagram illustrating a communication network, a peripheral device and a WLAN terminal operating according to the invention.

DETAILED DESCRIPTION OF THE INVENTION In the following, a preferred embodiment of the invention will be described by means of the enclosed drawings. Figure Ia and Ib are schematic block diagrams illustrating a prior art WLAN terminal operating according to the IEEE standard 802.11, which hereby is incorporated by reference.

In Figure Ia the WLAN terminal, even generally denoted as a WLAN station, is operating in the infrastructure mode connected to an Access Point (AP) of a communication network. In the infrastructure mode according to the IEEE standard 802.11, peripheral devices, e.g. headset for mobile terminals , PAN, Personal Computers etc, has to be accessed from the WLAN terminal via an Access Point (AP), if the WLAN terminal is running in the infrastructure mode. The WLAN terminal and the peripheral device each one comprises a WLAN communication unit for transmitting and receiving data packages over an air interface. If the WLAN terminal is a mobile radio telecommunication terminal running a voice-over-IP call, this has to be done in the infrastructure mode and a wireless headset has also to be connected to the terminal via the Access Point AP. The WLAN terminal is not capable of running a direct link or connection over the air interface in this mode. The terminal is also provided with at least one computer or digital processing unit, such as a central processing unit (CPU), connected to In/ Out-units and program software and data storage means (not shown) for controlling the functions, different equipment units and other applications of the terminal.

In figure Ib, the WLAN terminal is connected directly over a wireless link or wireless connection to the peripheral device, and the WLAN terminal is operating in the independent mode. It will not be possible to connect the WLAN terminal to an Access point without terminating the direct air interface link to the peripheral WLAN device.

The terminal and the peripheral device is forced to operate in the same mode, or state. The WLAN communication unit comprises two state-machines, one state-machine operating exclusively in the infrastructure mode, and a second state-machine operating exclusively in the independent mode. Hence, the two state-machines operates mutually exclusive. A state- machine is typically a computer program software in combination with a digital processing unit/ device (processor). Different state- machines can be implemented as different software on the same processor.

In figure 2, a WLAN terminal according to the invention is illustrated, which is capable of operating in a third, mixed mode, combining infrastructure mode and independent mode. A WLAN terminal according the invention will also comprise a two state machine capable of operating mutually exclusive. However, a WLAN terminal according to the invention will comprise a mixed mode means for running the first and second state-machines at the same time, thus making it possible to operate the WLAN terminal in a mixed mode combining the infrastructure mode and the independent mode. This third mode is comparable in many features to the scatter mode known from the Bluetooth standard, which hereby is incorporated by reference, but with the difference that the hard ware and soft ware is adapted to WLAN technology and structure. As illustrated in figure 2, the WLAN terminal is connected directly over a wireless link or wireless connection to the peripheral device operating in the independent mode, and at the same time, simultaneously, connected to an AP of a communication network. This mode is selectable by a user of the terminal if the user wants to use a peripheral device, such as a head set, in combination with the terminal, such as a mobile radio telecommunication terminal. By means of the mixed mode means, the terminal and the peripheral device may therefore operate in different modes, or states. To achieve said operation possibility, the mixed mode means which comprises following means:

1. TSF means

The network timing functionality (TSF, Time Synchronization Function) in the station needs to simultaneously keeping track of two independent and mutual disjoint and asynchronous time reference domains. This is solved by implementing two virtual soft TSF means and separating them from the physical TSF timer in the station;

2. Network attribute list

The station needs to simultaneously be able to handle two different network segments, each with its own cell attribute list. This is done by keeping multiple (2) instances of network attribute lists. The network attribute list contain information such as allowed transmission rates, security policy, quality of service policy, beacon transmission timing, network id, etc.

3. Transmit timing accelerator means

In particular, the station needs to simultaneously be able to comply to two different sets of media access timing rules. This is done by hardware support in terms of multiple hardware transmit timing accelerator means, each with its own set of controlling parameters;

4. Mac address means

The station need to be able to, over one single physical interface, present two different network interfaces to the to the host environment in which it operates. This is done by simultaneously maintaining two different mac addresses and, in the host driver part, announce two different and simultaneous network connections; 5. Different power management state machines

In cases where the two different networks are operating on different radio channels, and due to the fact that the proposed solution only requires one single radio module, and in order not to loose any incoming data, the station need to inform network peer units of the stations momentarily availability to communication. This is done by keeping and coordinating different power management state machines, one for each network instance.

When setting up a wireless communication link or connection, there is some properties of the connection to the AP, that has capabilities, which is announced via the data information signalling of the connection establishment. Said property information will be stored in data storing means within the terminal. As protocol is used for the data information transmission, capability information will be used in the lowest protocol level, controlling the timing of the protocols. This timing derived from the infrastructure mode connection, which also sometimes is denoted infrastructure network, is also used for controlling the establishment of the timing in independent mode connection, which also is denoted independent network. In this way, one connection or network is characterized as superior, and the other connection or network is subordinate. Hence, the infrastructure network is superior to the independent ditto. The hard ware in the terminal has to support both connections/networks. The capability properties are therefore filtered out from the superior network to be used in the subordinate network for achieving that the two networks will be as compatible as possible. A routing means is therefore provided within the terminal according to the invention for accomplishing correct distribution of the data frames /packages to the networks respectively. The peripheral device need only support Independent operation mode, and the implementation may be more compact with smaller memory footprint.

During the establishing of the different connection following synchronisation measures will be performed. In the infrastructure mode connection/ network, the WLAN terminal will correspond to a client party and the AP the server party. The peripheral device will be passive waiting for the establishment of a connection. In the independent mode, if a terminal or a peripheral device doesn't discover any synchronizer, it will immediately take the synchronizer function by starting beacon signalling. Due to the timer change and/ or disturbance, synchronizer function is able to jump, be transferred, from one terminal/ device to another device /terminal.

One benefit with the present invention is that it possible to connect a number of headsets to the same WLAN terminal and thereby establishing conference calls with a number of participants.

The present invention is not limited to the above-described preferred embodiments. Various alternatives, modifications and equivalents may be used. Therefore, the above embodiments should not be taken as limiting the scope of the invention, which is defined by the appended claims.

Claims

PATENT CLAIMS

1. WLAN (Wireless Local Area Network) terminal capable of operating in one infrastructure mode or in a second mode, an independent mode, mutually exclusive, characterized in that the WLAN terminal comprises one state-machine intended for controlling the WLAN terminal in WLAN terminal in the Infrastructure mode, a second state-machine for controlling the WLAN terminal in the Independent mode, and mixed mode means for running the first and second state- machines in a mixed mode, wherein the WLAN terminal is capable of transferring data information in the infrastructure and independent modes simultaneously.

2. WLAN terminal according to claim 1, characterized in that the mixed mode means is realized as hardware for controlling the timing and other properties for achieving that the two modes in the mixed mode and networks will be able to operate simultaneously, and which accomplishes the WLAN terminal capability of transferring data information in the infrastructure and independent modes simultaneously.

3. WLAN terminal according to claim 1, characterized in that the mixed mode means is realized as computer readable software means for controlling the timing and other properties for achieving that the two modes in the mixed mode and networks will be able to operate simultaneously, which software means, when having been loaded into a digital processor unit (CPU) in said terminal, accomplishes the WLAN terminal capability of transferring data information in the infrastructure and independent modes simultaneously.

4. WLAN terminal according to any of the preceding claims, characterized in that the mixed mode is a scatter mode adapted for and working according to WLAN technology and standard.

5. WLAN terminal according to any of the preceding claims, characterized in that the terminal also comprises routing means for distributing communicated data packages or frames.

6. A method for operating a WLAN (Wireless Local Area Network) terminal in different modes, said WLAN terminal is capable of operating in one infrastructure mode or in a second independent mode, mutually exclusive, characterized by the step of setting the WLAN terminal in a mixed mode by means of a mixed mode means for running the WLAN terminal in the infrastructure and independent modes simultaneously.

7. A method according to claim 6, characterized in that the mixed mode means is realized as computer readable software means for controlling the timing and other properties for achieving that the two modes in the mixed mode and networks will be able to operate simultaneously, which software means, when having been loaded into a digital processor unit (CPU) in said terminal, accomplishes the WLAN terminal capability of transferring data information in the infrastructure and independent modes simultaneously.

8. A method according to claim 6 or 7, characterized in that the mixed mode means is realized as hardware for controlling the timing and other properties for achieving that the two modes in the mixed mode and networks will be able to operate simultaneously, and which accomplishes the WLAN terminal capability of transferring data information in the infrastructure and independent modes simultaneously.

9. A method according to any of claims 6-8, characterized in that the mixed mode means is realized as computer readable software means for controlling the timing and other properties for achieving that the two modes in the mixed mode and networks will be able to operate simultaneously, which software means, when having been loaded into a digital processor unit (CPU) in said terminal, accomplishes the WLAN terminal capability of transferring data information in the infrastructure and independent modes simultaneously.

10. A method according to any of claims 6-9, characterized in that the terminal is operated in mixed mode corresponding to a scatter mode adapted for and working according to WLAN technology and standard.

11. Computer program product comprising a computer usable medium and a software code means loadable into an internal memory storage of a data processing unit within a controller of a WLAN terminal, which will be capable of setting the WLAN terminal in a mixed mode according to any of claims 1-5 when the software code means is executed by the data processing unit within the controller in the WLAN terminal.

12. A computer program comprising software code means stored on a computer usable medium, from which the software code means is readable by a computer means, the software code means is capable of causing a data processing unit in a computer means of a WLAN terminal to set the WLAN terminal in a mixed mode according to any of claims 1-5.

13. The computer program according to claim 12, characterized in that the computer usable medium is any of a record medium, a hard disk, floppy disk, floppy disk drive, optical disk drive, a computer memory, a Read-Only Memory, magnetic cassettes, flash memory cards, digital video disks, random access memories or an electrical carrier signal.