CN100438348C - Antenna steering and hidden node recognition for an access point - Google Patents
Antenna steering and hidden node recognition for an access point Download PDFInfo
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- CN100438348C CN100438348C CNB2004800171353A CN200480017135A CN100438348C CN 100438348 C CN100438348 C CN 100438348C CN B2004800171353 A CNB2004800171353 A CN B2004800171353A CN 200480017135 A CN200480017135 A CN 200480017135A CN 100438348 C CN100438348 C CN 100438348C
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Abstract
The invention proposes a method for operating the accessing point in the wireless local network (WLAN). The accessing point comprises a directional antenna used for communicating with a plurality of distance stations; the directional antenna has a plurality of antenna patterns. The method includes that based on a measured signal quality corresponding to the antenna patterns, the correlation is established between the accessing point and each distance station to generate an antenna data; the corresponding measured signal quality is determined, basing on the communication of the accessing point and each distance station; the method also includes that based on the antenna data, a better antenna pattern for each distance station is determined; a distance station and the corresponding better antenna pattern which communicates with the distance station are selected; based on the antenna data base, if the other unselected distance stations are not informed during the communication process is judged before the communication of the selected distance is processed.
Description
Technical field
The present invention is about the category of WLAN, particular words be antenna steering algorithm about the access point that in WLAN, operates.
Background technology
There are various standards to allow that distant station (such as portable computer) moves in a WLAN (WLAN) and are connected to an access point (AP) that is connected to a cable network via radio frequency (RF) transmission.This cable network is commonly called wiring system (distribution system).Above-mentioned various standard comprises IEEE 802.11 standards and corresponding alphabetical revision version thereof, such as 802.11b and 802.11g.
Physical layer in distant station and in access point provides low order transmission to use to allow these stations communicate by letter with access point.On this physical layer, there is a medium access control (MAC) layer to provide such as authenticate, remove services such as authentication, the right of privacy, foundation association and disassociation.
In operation, when a distant station is reached the standard grade, at first can between the physical layer in this station and the access point, set up online.Just can connect the MAC layer then.Generally speaking, with regard to distant station and access point, physical layer RF signal utilizes unipole antenna to transmit and receive.
One unipole antenna is with all direction radiation, with regard to a vertical orientation assembly substantially with a horizontal plane radiation.Unipole antenna is easy to take place the communication quality deterioration between distant station and the access point, for example causes radio wave signal to reflect or diffraction because of object between two parties.Object comprises wall, desk and people for instance between two parties.These objects produce multipath, the decline of normality statistics, Rayleigh (Rayleigh) decline etc.Therefore, once had for the effort that the Signal Degrade that effect causes such as alleviates therefore.
A kind of technology that is used for offseting the deterioration of RF signal is to use two antennas that the diversity effect is provided.This two antenna is coupled to and is in the antenna diversity switch that distant station and access point one of them or the two have concurrently.Use two antennas in the hope of the basic theory of antenna diversity effect to be: no matter at any given time, at least one antenna receives that possibly one is not subjected to the signal of Multi-Path Effects in the middle of the described antenna.Therefore, this antenna promptly is that distant station or access point are chosen the antenna that carries out transmitting/receiving signal via this antenna diversity switch.Need to solve the interior distant station of WLAN and the problem of the RF Signal Degrade between an access point but still have.
In addition, do not know that at a distant station access point and a selected distant station ongoing communication and this distant station in attempting to communicate with this access point another problem can take place.Therefore can bump at access point, this causes a situation that is called as hidden node problem, and this is because be not that each distant station can both be with each other distant station direct communication in this network in a WLAN.
Summary of the invention
Because above-mentioned background, a purpose of the present invention is to improve in the WLAN communicating by letter between the access point and distant station, particularly concealed nodes aspect.
A kind of improvement that surmounts simple diversity effect is the antenna steering program that is used in the access point (that is radio network gateway) of WLAN by a kind of.Directional antenna improves the circulation of network, and strengthens the scope between access point and distant station (that is wireless user's device).One directed antenna in most of the cases provides one to be higher than the signal to noise ratio of omnidirectional antenna, thereby allows that link operates with higher data transmission rate.
This antenna steering program can be in medium access control (MAC) layer that is present in access point, and is that the basis is chosen a best or preferable directional antenna and arranged with the signal quality metrics that can be provided by physical layer after the distant station received signal.
According to principle of the present invention, in the process of the exchanges data between for example login, authentication or follow-up access point and a selected distant station, judge a preferred direction of being controlled access point antenna.In one embodiment, by making this judgement at the software or the firmware of access point running.This access point antenna Control Software/firmware can be set up a database that comprises distant station identity and the antenna direction relevant with this station to reach the optimization usefulness of communicating by letter.
Can use the arrange in pairs or groups intrinsic diversity of traditional 802.11 equipment of hardware to select the circuit running to choose preferable directional antenna angle.Access point can utilize to post a letter and cause distant station to launch a probe response signal, and wherein this access point is measured the signal quality of this probe response signal.Whether this access point can be relatively should carry out a new antenna scanning operation to last tolerance corresponding to the signal that receives from distant station with an omnidirectional antenna pattern to judge corresponding to the tolerance of the signal that receives from distant station with a directed antenna mode.Hiding node occurs if access point is judged, it may utilize such as the defined request transmission/clears to send of 802.11 standards (RTS/CTS) cause a protection mechanism.
Adding with a directed antenna allly has double advantage in access point: promote multi-user's ability more in the circulation of indivedual distant stations and the network enabled.In most of RF environment, the signal bits that distant station receives will definitely be via allowing access point improve with the mode of the shaping antenna beam emission of the direction at this station of aiming.This shaping antenna beam can provide a 3-5dB gain benefit that is better than being deployed in traditionally the omnidirectional antenna of access point for instance.The signal level that strengthens allows that linking with higher data transmission rate between access point and the distant station operates, and particularly covering the outer frequency band in ripple district.This directional antenna manipulative procedure is present in the access point with the operation of support with distant station.
More particular words it, the present invention is directed to the method for the access point in a kind of operate wireless LAN (WLAN), this access point comprises one and is used for the directional antenna that communicates with a plurality of distant stations, this directional antenna comprises a plurality of antenna patterns, this method comprises: produce an antenna database by making between this access point and each distant station to set up related mode corresponding to a corresponding measures signal quality of described a plurality of antenna patterns, described corresponding measures signal quality is based on this access point and judges with communicating by letter of each distant station with it; For each distant station serves as that a preferable antenna pattern is judged on the basis with this antenna database; The corresponding preferable antenna pattern of choosing a distant station and communicating with; And serve as basis and with before this selected distant station is communicated by letter with this antenna database, be not selected the relevant corresponding signal quality of distant station by relatively more relevant measures signal quality and with using the described of identical preferable antenna pattern, thereby judge whether have any distant station that is not selected also not know in should selected distant station whether taking place via the preferable antenna pattern of this correspondence with the reality of communicating by letter between access point with the preferable antenna pattern of this selected distant station.
The corresponding signal quality that records can comprise a received signal intensity reading, one carrier wave-interference ratio, one energy-bit than and a signal to noise ratio at least one of them.
Described a plurality of antenna pattern can comprise an omnidirectional antenna pattern, if and describedly be not selected in the middle of the distant station at least one standing-meeting and also do not know in taking place in that these communications are actual through judging, then this method can more comprise via this omnidirectional antenna pattern described a plurality of distant stations are sent an active clear to send message.This clear to send message has a not use address that does not correspond to arbitrary station in the middle of described a plurality of distant station.
Another selection, if describedly be not selected in the middle of the distant station at least one standing-meeting and also do not know in taking place in that these communications are actual through judging, then this method can comprise more that with a forward link direction described a plurality of distant stations being launched a request via this omnidirectional antenna pattern sends messages, receive a clear to send message from this selected distant station, this selected distant station is launched a Frame, and receive an affirmation message from this selected distant station.With regard to a reverse link direction, the present invention can comprise more that receiving a request from this selected distant station sends message, this selected distant station is launched a clear to send message, receive a Frame, and message is confirmed in this selected distant station emission one from this selected distant station.
The step that produces antenna database can be undertaken by at least three kinds of modes.A kind of scheme is the control frame that utilizes in the forward link, and second kind of scheme is the control frame in utilizing a backward chaining, and the third scheme is to utilize detectable signal.
Utilize the step of the control frame generation antenna database in the forward chaining to comprise that making this access point and described a plurality of distant station be exchanged for the basis with the packet data that comprises a plurality of control frames and a Frame in a forward link communicates, and the step that produces antenna database comprises: one first antenna pattern via this directional antenna is solicited first control frame from this first distant station reception one, this first distant station is launched one first Frame, one second antenna pattern via this directional antenna receives one second control frame from this first distant station, and the signal quality of measuring first control frame that receives via this first antenna pattern reaches the signal quality of second control frame that receives via this second antenna pattern.Repeat above step at remaining line pattern every day.
In addition, this method more comprises the signal quality that repeats second control frame that this receiving step and this step of transmitting receive with the signal quality of measuring first control frame that receives via this first antenna pattern and via this second antenna pattern at each distant station.Received this first control frame comprises a clear to send message, and received this second control frame comprises that one confirms message.
The step of utilizing the interior control frame of a backward chaining to produce antenna database comprises makes this access point receive one first control frame via one first antenna pattern of this directional antenna from one first distant station, this first distant station is launched one second control frame, one second antenna pattern via this directional antenna receives one first Frame from this first distant station, and measurement reaches the signal quality of first Frame that receives via this second antenna pattern via the signal quality of first control frame of this first antenna pattern reception.Repeat above step at remaining line pattern every day.
This method more comprises the signal quality that repeats first Frame that this receiving step and this step of transmitting receive with the signal quality of measuring first control frame that receives via this first antenna pattern and via this second antenna pattern at each distant station.Received this first control frame comprises that a request sends message, and second control frame that is launched comprises a clear to send message.
Utilize detectable signal to produce the step of antenna database to comprise the directional antenna of omnidirectional's angle and a plurality of directional angle, and the step that produces antenna database comprises chooses one first distant station, omnidirectional's angle via this directional antenna is launched one first detectable signal to this first distant station, and measures first a probe response signal in response to this first detectable signal that receives from this first distant station via this omnidirectional's angle.Via each angle in the middle of a plurality of directional angle of this directional antenna this first distant station is launched corresponding second detectable signal, and measure second a probe response signal in response to this corresponding second detectable signal that receives from this first distant station via each directional angle.
When using detectable signal, this method more comprises in the middle of described a plurality of distant stations chooses next distant station, and this next one is selected the step of distant station repeat its transmission first and second detectable signals and measured the step of selecting the first and second probe response signals of distant station reception from this next one.Repeat above step at each remaining in the middle of described a plurality of distant stations distant station.This first detectable signal comprises that a request sends (RTS) message and this first probe response signal comprises a clear to send (CTS) message, and this second detectable signal comprises that a RTS message and this second probe response signal comprise a CTS message.
This access point is with an IEEE 802.11 standards and one of them the standard running of an IEEE 802.16 standards.This directional antenna comprises at least one active block and a plurality of passive block.
Another viewpoint of the present invention is at a kind of access point that is used for WLAN (WLAN), and it comprises: a directed antenna, and it includes a plurality of antenna patterns; An and controller, it is connected in this directional antenna, in order to control this directional antenna, this controller is communicated by letter with a plurality of distant stations by carrying out the following step: by relevant with each distant station corresponding to the corresponding signal quality that records of one of described a plurality of antenna patterns, to produce an antenna database, for each distant station serves as that a preferable antenna pattern is judged on the basis with this antenna database, the corresponding preferable antenna pattern of choosing a distant station and communicating with, and based on this antenna database and with before this selected distant station is communicated by letter, be not selected the relevant corresponding signal quality of distant station by relatively more relevant measures signal quality and with using the described of identical preferable antenna pattern with the preferable antenna pattern of this selected distant station, thus judge whether have any distant station that is not selected also do not know this selected distant station with whether take place via the reality of communicating by letter between the access point of the preferable antenna pattern of this correspondence.
For further specifying above-mentioned purpose of the present invention, design feature and effect, the present invention is described in detail below with reference to accompanying drawing.
Description of drawings
Figure 1A is the sketch of the WLAN (WLAN) of utilization principle of the present invention;
Figure 1B is the sketch that is carrying out an access point of antenna scanning in the WLAN of a Figure 1A;
Fig. 2 A one has the sketch of Figure 1A access point of exterior orientation aerial array;
Fig. 2 B is the sketch of Fig. 2 A access point, and wherein this directional antenna array is merged in the inner pcmcia card;
Fig. 3 A is the sketch of Fig. 2 A directional antenna array;
Fig. 3 B one is used for choosing the sketch of an antenna module state of switch of Fig. 3 A directional antenna;
Fig. 4 is the calcspar of a utilization according to Figure 1A access point of subsystem, layer and an antenna steering program of principle of the present invention;
Fig. 5 A one optionally is used for the signal sketch of Fig. 4 antenna steering program;
Fig. 5 B one optionally is used for the substitution signal sketch of Fig. 4 antenna steering program;
Fig. 6 is the alternative calcspar of a Fig. 4, wherein uses the antenna diversity circuit;
Fig. 7 one optionally is used for the signal sketch of the utilization concealed nodes technology of Fig. 4 antenna steering program;
Fig. 8 one possesses the vertical view of two-way the 1st figure network of posting a letter;
Fig. 9 one possesses the vertical view of the 1st figure network of antenna beam reading;
Figure 10 is one to be the flow chart of method of the access point of fundamental operation WLAN with the space diversity according to the present invention;
Figure 11 is one to be the flow chart of method of the access point of fundamental operation WLAN with the detectable signal according to the present invention;
Figure 12 and Figure 13 are respectively to be the flow chart of method of the access point of fundamental operation WLAN with the control frame in forward direction and the backward chaining according to the present invention; And
Figure 14 one is recognized as the flow chart of method of the access point of fundamental operation WLAN with concealed nodes according to the present invention.
Embodiment
Appended graphic the present invention of illustrating in greater detail of preferred embodiment of the present invention is drawn in following reference.Right the present invention can also many multi-form enforcement and should be illustrated as and only limit to the described embodiment of this specification; These embodiment just are used for allowing this specification more thoroughly complete, and can contain scope of the present invention fully to haveing the knack of this skill person.Full content indicates same components with same numbers, and uses the stress mark to indicate similar assembly in alternate embodiment.
Explanation has the WLAN (WLAN) 100 of a wiring system 105 with reference to Figure 1A at the beginning.Access point 110a, 110b and 110c are connected to wiring system 105 via wired connection such as cable data network connected mode.Each access point 110a, 110b and 110c have respective regions 115a, 115b, the 115c that can communicate by letter with distant station 120a, 120b, 120c via radio frequency (RF) signal. Distant station 120a, 120b, 120c are equipped with the WLAN hardware and software to insert wiring system 105.In the following description, when desire is made a general name address to access point, distant station and zone, can use reference number 110,120 and 115 respectively.
Current techniques provides antenna diversity for access point 110 and distant station 120.Antenna diversity allows that access point 110 and distant station 120 are that the basis is chosen two antennas and wherein one provided the work of transmitting and receiving with the signal quality of receiving.A reason of bypassing other antenna and choosing an antenna occurs in the situation of multipath decline, wherein one adopts the signal in two different paths to cause the signal cancellation effect at an antenna, but can not at another antenna.Another example is to cause in the interference because of two unlike signals that the same antenna is received.Choose two antennas wherein another reason of one be because environment change, for example shown in arrow 125, taken to from the 3rd district 115c in the first or second district 115a, the 115b as a distant station 120c.
Figure 1B is the calcspar of a subclass of network shown in Figure 1A 100, wherein draws the directional antenna lobe 130a-130i of the access point 110b of utilization principle of the present invention in more detail.Directional antenna lobe 130a-130i also can totally be denoted as reference number 130.Access point 110b in an environmental scanning process in regular turn by antenna lobe 130 to judge a preferable antenna direction.
In the one scan process, access point 110b uses just like Fig. 2 A and the more detailed directional antenna scanning search distant station 120b RF signals transmitted of drawing of Fig. 2 B.In each scanning direction (that is angle or antenna pattern), access point 110b measures a signal or probe response and calculates a corresponding tolerance of this scanning angle.The example of tolerance comprises received signal intensity reading (RSSI), carrier wave-interference ratio (C/I), and energy-bit is than (Eb/No), or other suitable tolerance of the quality of received signal or signal environment, such as signal to noise ratio (snr).One combination of these measuring values also can be used to judge best or preferable antenna alignment, can understand easily as haveing the knack of this skill person.Record signal quality metrics according to these, access point 110b judges the preferable aerial angle or the direction of communicating by letter with distant station 120b.
These scannings can be certified and taken place with before or after wiring system 105 combines at distant station 110b.Therefore, initial antenna scanning may be to finish in the MAC layer.Another selection, initial antenna scanning can be beyond the MAC layer and finish.Similarly, authenticated and can be with the scanning that takes place after wiring system 105 combines and in the MAC layer, finish or finish at distant station 110b by the program that occurs in beyond the MAC layer.
Fig. 2 A is the sketch of the access point 110 of a use one exterior orientation aerial array 200a.Directional antenna array 200a comprises five one pole passive antenna assembly 205a, 205b, 205c, 205d and 205e and an one pole active antenna assembly 206. Passive antenna assembly 205a, 205b, 205c, 205d and 205e totally indicate with reference number 205 hereinafter.Directional antenna array 200a is connected to access point 110 via a universal serial bus (USB) port 215.Directional antenna array 200a also accepts being connected of other type with 110 of access points.
Passive antenna assembly 205 in the directional antenna array 200a is coupled to active antenna assembly 206 autoeciously to allow scanning.In this manual, at least one antenna beam that " scanning " means directional antenna array 200a can rotate with the increment relevant with the quantity of passive antenna assembly 205, and it optionally can revolve three-sixth turn.
One of directional antenna array 200a describes in detail and to be provided on January 24th, 2002 invention disclosed name and to be called in No. the 2002/0008672nd, the U.S. Patent Publication case of " adaptive antennas that is used for wireless communication system ", and this case is incorporated herein by reference and it has been amortized to existing assignee of the present invention.The signal of receiving or launching with directional antenna array 200a is that the sample method of basic optimization antenna direction also is disclosed in this case.
Directional antenna array 200a also can be used to an omni-directional mode so that an omnidirectional antenna pattern to be provided.Access point 110 can adopt an omni patterns to launch or receive.Access point 110 also can use selected directional antenna in receiving to distant station 120 emissions or from this distant station.
Fig. 2 B one possesses the isometric views of the access point 110 of an inner orientation antenna 220b.In this embodiment, directional antenna array 200b is positioned on the pcmcia card 220.Pcmcia card 220 is to carry and be connected in a processor (not shown) by access point 110.Directional antenna array 200b provides the identical functions with directional antenna array 200a shown in Fig. 2 A.
It will be appreciated that the directional antenna array that numerous other forms are still arranged can use.Example comprise be disclosed in the denomination of invention of awarding card on January 4th, 2003 for No. the 6515635th, the United States Patent (USP) of " adaptive antennas that is used for wireless communication system " and on March 28th, 2002 bulletin denomination of invention be No. the 2002/0036586th, the United States Patent (USP) bulletin case of " adaptive antennas that is used for wireless communication system ", the two is incorporated herein by reference and it has been amortized to existing assignee of the present invention.
Fig. 3 A is just like the preceding described details drawing that comprises the directional antenna array 200a of passive antenna assembly 205 and active antenna assembly 206.Directional antenna array 200a also comprise one with the ground plane 330 of passive antenna electrical component coupling, it is described to see below Fig. 3 B.
Still with reference to Fig. 3 A, directional antenna array 200a provides one from antenna module 205a and the oblique directional antenna lobe of leaving 300 of 205e.This is in the sign that a reflective-mode and antenna module 205b, 205c and 205d are in a transmission mode for antenna module 205a and 205e.In other words, coupling mutually between active antenna assembly 206 and the passive antenna assembly 205 allowed directional antenna array 200a scan orientation antenna lobe 300, and in present case, this lobe is led as shown in the figure because of the pattern of both establishing of passive block 205.As have the knack of this skill person and can understand, the different mode combination of passive antenna assembly 205 can cause different antenna lobes 300 patterns and angle.
Fig. 3 B one can be used to passive antenna assembly 205 is set at the sketch of the example circuit of reflective-mode or transmission mode.Reflective-mode is indicated by a representative long dotted line 305, and transmission mode is indicated by a short dash line 310.Representative mode 305 and 310 is respectively to cause via the mode that an Inductive component 320 or a capacitance component 325 are coupled to a ground plane 330.Passive antenna assembly 205a is to carry out via a switch 315 by coupling of Inductive component 320 or capacitance component 325.Switch 315 can be the mechanical switch or the electric switch that passive antenna assembly 205a can be coupled to ground plane 330.Switch 315 is to set via a control signal 335.
That be coupled to ground plane 330 via inductor 320 is passive antenna assembly 205a, and it is prolonged shown in long representative dotted line 305 effectively.This can be considered is to provide one " backboard (backboard) " for a RF signal that is coupled in passive antenna assembly 205a via coupling mutually of passive antenna assembly 205a and active antenna assembly 206.In Fig. 3 A case, the two is connected in ground plane 330 via corresponding Inductive component 320 passive antenna assembly 205a and 205e.At the same time, in Fig. 3 A example, other passive antenna assembly 205b, 205c and 205d are electrically connected on ground plane 330 via corresponding capacitance assembly 325.
The capacitive coupling effect is shortened the passive antenna assembly effectively shown in short representative dotted line 310.All the capacitive coupling effect of passive block 325 makes directional antenna array 200a become an omnidirectional antenna effectively.It will be appreciated that also the technology of coupling that substitutes to be used between passive antenna assembly 205 and the ground plane 330, for example delay line and lumped impedance.
Jump to Fig. 9, it provides by utilization directional antenna array 200a or 200b and makes access point 110b produce the vertical view of an omnidirectional antenna pattern 905 and a directed antenna pattern 910.Access point 110b communicates by letter with a plurality of station 120a-120d.Because access point 110 is installed as and is not had barrier or mobile reflector in its vicinity (for example being mounted on the wall on eminence or the ceiling) usually by long distance, the selection of preferable antenna pattern direction probably not can with the online whole process of a given distant station 120 in change.
Any distant station in contention (CP), sends on the access point 110b row link data frame by selected distant station 120c and utilizes the omnidirectional antenna pattern to receive, because all may be launched this frame.With regard to big frame, network configuration may require distant station to adopt request transmission/clear to send (RTS/CTS) mechanism to subscribe wireless medium.In this case, access point 110b can a directed pattern receive to strengthen the message transmission rate of uplink.How much this is the message transmission rate selection algorithm that depends in distant station 120c utilization.
In downlink transmissions, access point 110b may determine to use in contention an omni patterns and a lower data transmission rate to launch little package.It is former because the distant station (such as distant station 120e) on the side of region of convergence " another " can't be heard the access point transmission content of sending from the directional antenna pattern back to its sensing.This is many " concealed nodes " problems of being familiar with, and wherein two distant stations 120 are not heard the other side mutually and finished emission at one time.In this case, this two distant station is 120c and 120e.A kind of avoid this problem, particularly to big Frame effective method hereinafter with reference to Fig. 7 explanation.
Be can be for providing the higher data transmission rate with downlink and uplink Frame as distant station 120 exchanges of network traffic main body with the directional antenna pattern at access point 110 places.Network on-line is maintained at the nominal gain of the omnidirectional antenna of access point 110.That is to say that distant station 120 can combine and keep online with access point 110 and need not use directional antenna 200a.
Must be defined as utilizing the omnidirectional of directional antenna 200a and the advantage of directional characteristic as the regular collection that table 1 provided.Table 1 comprises the address and the selection of existing antenna direction thereof of the relevant distant station 120 of current and access point 110.Table 1 can be that basic description example antenna direction is selected according to the frame sequence of 802.11 standards (table 21 and 22 within it).In table 1, " Dir " finger direction, " UL " refers to uplink, and " DL " refers to downlink.
Table 1-example antenna selective rule
| Sequence | Dir | It line options | |
| Beacon | DL | Omnidirectional | |
| Data | DL | Directed | Referring to Fig. 5 A |
| The RTS-CTS data | UL | Omnidirectional/orientation | Referring to Fig. 5 B |
One program can be judged the regular collection explanation of when choosing omni patterns and when choosing a directed pattern by one.For instance, access point 110 can be chosen a directed pattern in the time interval to 120 emissions of single distant station or reception the time.
One calcspar that the interface of access point 110 is shown is plotted in Fig. 4.Icon access point 110 comprises a plurality of subsystems and layer.One antenna subsystem 405 can comprise directional antenna 220b and be used for operating support circuit, bus and the software of this directional antenna.Antenna subsystem 405 has a common boundary with physical layer 410 and provides RF signal 412 to the latter.
MAC layer 415 also sends to Frame 429 other program (not shown).Icon physical layer 410, MAC layer 415 and antenna steering program 420 can be and be present in the controller 400.Antenna steering program 420 can be for instance and is stored in the internal memory, this internal memory can be one independently one in internal memory or the processor embed internal memory.
Hereinafter illustrate according to the present invention and be used for judging the various technology of a directed antenna 220b being pointed to the preferred direction of a distant station 120 from an access point 110.First kind of technology used a space diversity choice mechanism.Second kind of technology utilization is in the detectable signal sequence of access point 110 and 120 exchanges of distant station.The third technology utilization control message (for example ACK or CTS) is made the signal quality measuring value of reception antenna direction at access point 110.The third technology can be applicable to forward direction and backward chaining the two.
First kind of technology supposes that existing 802.11 devices are included the diversity scanning/control of antenna switch type in and following 802.11 devices such as the 802.11a/802.11g/802.11n also can support the switch type diversity.This first technology is authenticated and with available after a network combines at a distant station 120.It supposes that initial antenna scanning is to finish in the MAC/ network layer protocol.Use an orientation or multi-component antenna 220a, this first technology can utilize diversity protocol to make aerial position/selection keep upgrading.
Modern with reference to Fig. 6, the effect of this first technology is as follows.Icon access point 110 ' comprises a controller 600 ' that is connected in antenna subsystem 405 '.Controller 600 ' comprises that one is endowed a physical layer 410 ' and the MAC layer (Fig. 4) to the access of antenna control signal.This MAC layer writes the sky line options in buffer A 605a ' and the buffer B 605b '.Buffer A 605a ' holds selected aerial position, and buffer B 605b ' holds an alternate antenna position.Physical layer 410 ' is also communicated by letter with a multiplexer 610 '.Physical layer 410 ' selects control mode that multiplexer 610 ' is sent a diversity selector switch control signal 607 ' with a traditional diversity, but is to use the diversity selector switch control signal of the content of control buffer A 605a ' or buffer B 605b ' in this case.
Should selected aerial position be during network authentication/, to select at the very start in conjunction with agreement.This alternate antenna position is any other aerial position (comprising an omni-directional mode).This alternate antenna position changes with a predefined procedure after receiving an effective package or after not receiving any package through one period scheduled time.
After successfully receiving a package, physical layer 410 ' sends at the received signal quality of this two aerial position the MAC layer and measures (signal strength signal intensity, signal to noise ratio, multipath/equalizer tolerance etc.).In the package receiving course, physical layer 410 ' is as operating as being used for 802.11 now; That is to say that switching and use receive best aerial position to package between this two aerial position.After physical layer 410 ' is received effective package, the signal quality metrics of this two aerial position is sent to the MAC layer.The MAC layer upgrades selected aerial position and alternate antenna position.It is best position, basis that this selected aerial position is replaced by with the data of receiving from physical layer 410 '.Can utilize filtering/hysteresis to avoid " ping-pong phenomenon (ping-ponging) " between two aerial positions.
As previously mentioned, the advantage of the existing 802.11 antenna switch type deversity schemes of this technology utilization.It will be appreciated that this first technology can comprise hardware, software/firmware or above combination.
Modern with reference to Figure 10, it will illustrate with the space diversity flow chart of the preceding method that is the access point 110 in fundamental operation one WLAN 100.From starting point (square 1000), this method comprises utilizes the existing angle of directional antenna 220b to communicate by letter with distant station 120, as square 1010.That carry out at square 1020 is a plurality of for using angle that inswept directional antenna 220b is used for communicating by letter with distant station 120 during lead code.What carry out at square 1030 is to measure via existing angle and a plurality of for the corresponding signal of receiving from distant station 120 with angle.At square 1040, during this lead code with record signal be the basis choose this existing angle or a plurality of for angle wherein an angle be one to continue the preferred angle communicate by letter with distant station 120.This method finishes at square 105.
Second kind of technology is with the emission of the RTS message of 110 pairs of distant stations 120 of access point and the distant station basis that is received as to the CTS message of access point response emission.802.11 standard also defines one and surveys requirements/probe response and exchange, this is used for judging link quality to other stations 120 by distant station 120 usually.
Be access in a little 110 be used for judging to a selected distant station 120 preferable pointing direction (shown in the 8th figure) time, access point 110 may directivity pattern 130 emissions one detection require signal with omni patterns and each, and measures from the signal quality of the probe response signal 810 of distant station 110 loopbacks in the corresponding pattern running.
The measurement of these response frames 810 becomes than aforementioned diversity selection technology it more the technology of leaning on.This second technology preferably is to use immediately with after access point 110 combines at a distant station 120 at least.Though use extra detection require/the probe response signal can impact network efficiency, these exchanges may seldom take place.
Modern with reference to Figure 11, it will illustrate with the detectable signal flow chart of the preceding method that is the access point 110 in fundamental operation one WLAN 100.From starting point (square 1100), this method is included in square 1110 and chooses a distant station 120, via omnidirectional's angle of directional antenna 220b this selected distant station is launched one first detectable signal at square 1120, and measure first a probe response signal in response to this first detectable signal of receiving from this selected distant station via this omnidirectional's angle at square 1130.
At square 1140, via each angle in the middle of a plurality of directional angle of directional antenna 200b selected distant station 120 is launched corresponding second detectable signal, and measure second a probe response signal in response to this corresponding second detectable signal of receiving from this selected distant station via each directional angle at square 1150.At square 1160, in the future free decide distant station 120 record the first probe response signal and the corresponding second probe response signal that records is stored in the antenna database.
At square 1170, serve as that a preferable directional angle is chosen at selected distant station 120 in the basis with the described second probe response signal that records.At square 1180, relatively derive from recording the first probe response signal and deriving from the second probe response signal that records of this preferable directional angle of this omnidirectional's angle.This first detectable signal comprises that a request sends (RTS) message and this first probe response signal comprises a clear to send (CTS) message.Similarly, this second detectable signal comprises that a RTS message and this second probe response signal comprise a CTS message.At square 1190, relatively be that the basis is chosen the preferable directional angle of this omnidirectional's angle or this and continued and select distant station 120 and communicate by letter with this.This method finishes at square 1195.
The utilization of the third technology is used in the control frame of the normality exchanges data of 120 of access point 110 and distant stations.This technology can be used in forward link communication and backward chaining and communicates by letter in the two.Because clear to send (CTS) and confirm that (ACK) message is to send with lower data transmission rate, access point 110 can be with these message comparison omni patterns 905 and the directivity pattern of selecting for use now 130.This is plotted in Fig. 5 A, in sky line options timing dotted line is arranged among the figure.It can be used as and is used for judging and selects for use direction 130 whether can possess the method that it surmounts the advantage of omni patterns 905 now.This advantage is switched normally based on a predetermined threshold in order to avoid having between two antenna patterns of similarity signal quality metric frequently.
For instance, during the CTS message, available omni-directional mode receives this message to calculate one first signal quality measuring value.During the ACK message, an available test antenna direction receives this message to calculate a secondary signal quality measuring value.Carry out the comparison of this first and second signal qualitys measuring value and judge whether this test antenna direction should be stored.That is to say whether directional pattern provides a gain that is higher than omni-directional mode.Also can carry out two comparisons between the different directional antenna directions.
The direction table 425 of Fig. 4 can add from the omnidirectional of aforementioned program and the signal quality measuring value of preferential direction antenna pattern.If advantage is low below a predetermined threshold, then access point 110 is replied to omnidirectional's selection and is utilized above-mentioned preceding two kinds of technology one of them carries out the antenna search.
Just in case replying, the lay-up period that distant station 120 enters an energy saver mode or do not have data to shift for a long time, access point 110 be the omni patterns selection.When distant station 120 becomes once more active, access point 110 can carry out the search of another antenna.
Modern with reference to Figure 12 and Figure 13, illustrate with the control frame in forward direction and the backward chaining to be the flow chart of the method for the access point 120 in fundamental operation one WLAN 100 respectively.From starting point (square 1200), this method is included in square 1,210 one first antenna pattern via directional antenna 220b in a forward link and receives one first control frame from distant station 120, and at square 1,220 one first Frame is transmitted to this distant station, and receives one second control frame via one second antenna pattern of this directional antenna from this distant station at square 1230.Measure the signal quality of second control frame that the signal quality and of first control frame of receiving via this first antenna pattern receives via this second antenna pattern at square 1240.Compare corresponding the record signal quality relevant at square 1250 with this first and second antenna pattern.If relevant with this second antenna pattern signal quality that records surpasses relevant signal quality one predetermined threshold that records with this first antenna pattern, then choose this second antenna pattern in order to distant station 120 is launched one second Frame at square 1260.First control frame of receiving comprises a clear to send message, and second control frame of receiving comprises that one confirms message.This method finishes at square 1270.
Being used for the control frame in the backward chaining is that the method for the access point 120 in fundamental operation one WLAN 100 comprises from starting point (square 1300), receive one first control frame via one first antenna pattern of directional antenna 220b from distant station at square 1310, at square 1,320 one second control frame is transmitted to this distant station, and receives one first Frame via one second antenna pattern of this directional antenna from this distant station at square 1330.Measure the signal quality of first Frame that the signal quality and of first control frame of receiving via this first antenna pattern receives via this second antenna pattern at square 1340.Compare corresponding the record signal quality relevant at square 1350 with this first and second antenna pattern.If relevant with this second antenna pattern signal quality that records surpasses relevant signal quality one predetermined threshold that records with this first antenna pattern, then choose this second antenna pattern and launch one second Frame by 110 pairs of distant stations of access point 120 at square 1360.First control frame of receiving comprises that a request sends message, and second control frame of emission comprises a clear to send message.This method finishes at square 1370.
The 4th kind of technology is a concealed nodes resist technology, and it provides a protection mechanism to reduce or the incidence of the concealed nodes of preventing when access point 110 uses a directed antenna 220b.Concealed nodes occur in be not in the network 100 all distant stations 120 can both hear in the communicating by letter of access point 110 and 120 of selected distant stations that therefore the distant station of not heard may be launched in being used at medium.This can cause collision, particularly at access point 110.
When access point 110 has the data that will be transmitted to a distant station 120, whether control program is set selected antenna direction in the mode of the direction table 425 of scintigram 4 has potential concealed nodes to judge.For instance, access point 110 can be just in contrast to the direction finding distant station 120 of selecting antenna direction.
With reference to the chronogram of Fig. 7, if judging, Control Software might have concealed nodes, access point 110 at first utilizes the omni-directional mode of antenna 220a that one known untapped MAC Address is launched a CTS message.This program is to be used for informing in the network that all distant stations 120 have an exchanging operation to take place and can not launch before exchange is finished.Access point 110 switches to the selected antenna direction of expection distant station 120 and communicates then.The another program that prevents hidden node problem is to hope that with first phase distant station 120 carries out four-way frame exchange agreement (RTS, CTS, data and ACK).
If Control Software judges that concealed nodes can not be arranged, access point 110 can not send the CTS message and can become in access point 110 antenna settings and begin communication immediately in the correct direction.If procotol has requirement, the RTS message must be fed to the receiver of expection, causes a CTS message to get back to access point 110 and is used as the affirmation message, shown in Fig. 5 A.
It is also noted that in the described program of reference Fig. 7 usefulness is not to be promoted by access point 110 emissions because of the RTS message, just only needs the CTS message because will make distant station 120 stop emission.The distant station of pointing out in the ID section of standard 802.11 agreement headers 120 guarantees that this assigning remote station receives Frame.
Modern with reference to Figure 14, the method that is recognized as the access point 120 in fundamental operation one WLAN 100 with concealed nodes is described.From starting point (square 1400), this method is included in 1410 by being that related mode is created an antenna database with the corresponding signal quality that records corresponding to a plurality of antenna patterns between access point 110 and each distant station 120.The described corresponding signal quality that records serves as that the basis is judged by access point 110 with itself and communicating by letter of each distant station 120.Serves as that the preferable antenna pattern be used for each distant station 120 is judged on the basis at square 1420 with this antenna database, and chooses a distant station and corresponding preferable antenna pattern to communicate at square 1430.At square 1440, based on this antenna database and with judge whether have any distant station that is not selected also not know in taking place in that these communications are actual before selected distant station is communicated by letter.This be by relatively more relevant with the preferable antenna pattern of this selected distant station record signal quality and when not being selected distant station and using identical preferable antenna pattern the mode of relevant corresponding signal quality judge.
If have a concealed nodes, then give expression to the message that access point 110 and selected distant station 120 are about to mutual communication in square 1450 broadcasting one.As previously mentioned, this broadcasting can be and is one and sends to the form of the active clear to send message of distant station 120 via the omni-directional antenna diagram case.This CTS has a not use address that does not correspond to any distant station 120.Another selection is carried out four-way frame exchange agreement (RTS, CTS, data and ACK) in case hidden node problem with selected distant station 120.This method finishes at square 1460.
Though below with reference to preferred embodiment of the present invention specifically scheme and explanatory note the present invention, have the knack of this skill person and will appreciate that can not break away from the invention scope that the claim item contained makes various variation with regard to form and details.For instance, access point is not limited to IEEE 802.11 standards.Foregoing access point antenna algorithm as have the knack of this skill person can understand the LAN that can be applicable to other type easily, such as the defined LAN of IEEE 802.16 standards.
Though the present invention describes with reference to current specific embodiment, but those of ordinary skill in the art will be appreciated that, above embodiment is used for illustrating the present invention, under the situation that does not break away from spirit of the present invention, also can make the variation or the replacement of various equivalences, therefore, as long as in connotation scope of the present invention in the scope to the variation of the foregoing description, claims that modification all will drop on the application.
Claims (28)
1. the method for the access point in the operate wireless LAN (WLAN), this access point comprise one and are used for the directional antenna that communicates with a plurality of distant stations, and this directional antenna comprises a plurality of antenna patterns, and this method comprises:
Produce an antenna database by making between this access point and each distant station to set up related mode corresponding to a corresponding measures signal quality of described a plurality of antenna patterns, described corresponding measures signal quality is based on this access point and judges with communicating by letter of each distant station with it;
For each distant station serves as that a preferable antenna pattern is judged on the basis with this antenna database;
The corresponding preferable antenna pattern of choosing a distant station and communicating with; And
With this antenna database is basis and with before this selected distant station is communicated by letter, be not selected the relevant corresponding signal quality of distant station by relatively more relevant measures signal quality and with using the described of identical preferable antenna pattern, thereby judge whether have any distant station that is not selected also not know in should selected distant station whether taking place via the preferable antenna pattern of this correspondence with the reality of communicating by letter between access point with the preferable antenna pattern of this selected distant station.
2. the method for claim 1 is characterized in that: the step of measuring the corresponding signal quality comprise judge a received signal intensity reading, one carrier wave-interference ratio, one energy-bit than or a signal to noise ratio.
3. the method for claim 1, it is characterized in that: described a plurality of antenna patterns comprise an omnidirectional antenna pattern; And wherein if describedly be not selected in the distant station that it is not also known at least in the actual generation of described communication for a moment through judging, then this method also comprises via this omni-directional antenna diagram case and sends an active clear to send message to described a plurality of distant stations, and this clear to send message has a not use address that does not correspond to any described a plurality of distant stations.
4. the method for claim 1, it is characterized in that: described a plurality of antenna patterns comprise an omnidirectional antenna pattern; And wherein if describedly be not selected in the distant station that it does not know that also then this method also comprises in the actual generation of described communication at least for a moment through judging:
In a forward link, launch a request via this omnidirectional antenna pattern and send message to described a plurality of distant stations;
Receive a clear to send message from this selected distant station;
Launch a Frame to selecting distant station; And
Receive one from this selected distant station and confirm message.
5. the method for claim 1, it is characterized in that: described a plurality of antenna patterns comprise an omnidirectional antenna pattern; And wherein if describedly be not selected in the distant station that it does not know that also then this method more comprises in the actual generation of described communication at least for a moment through judging:
In a backward chaining, receive a request and send message from this selected distant station;
Launch a clear to send message to selecting distant station;
Receive a Frame from this selected distant station; And
Emission one confirms that message is to selecting distant station.
6. the method for claim 1, it is characterized in that: this access point and described a plurality of distant station are exchanged for the basis with the packet data that comprises a plurality of control frames and a Frame in a forward link, communicate, and produce antenna database, comprising:
One first antenna pattern via this directional antenna is solicited first control frame from one first distant station reception one;
Launch one first Frame to this first distant station;
One second antenna pattern via this directional antenna receives one second control frame from this first distant station;
One signal quality of one signal quality of this first control frame that measurement is received via this first antenna pattern and this second control frame of being received via this second antenna pattern; And
Repeat above step at any remaining antenna pattern.
7. method as claimed in claim 6 is characterized in that: also comprise the signal quality that repeats second control frame that this receiving step and this step of transmitting received with the signal quality of measuring first control frame that is received via this first antenna pattern and via this second antenna pattern at each distant station.
8. method as claimed in claim 6 is characterized in that: this first control frame that this received comprises a clear to send message, and this second control frame that this received comprises that one confirms message.
9. the method for claim 1, it is characterized in that: this access point and described a plurality of distant station are exchanged for the basis with the packet data that comprises a plurality of control frames and a Frame and communicate in a backward chaining, and produce antenna database, and it comprises:
One first antenna pattern via this directional antenna receives one first control frame from one first distant station;
Launch one second control frame to this first distant station;
One second antenna pattern via this directional antenna receives one first Frame from this first distant station;
One signal quality of one signal quality of this first control frame that measurement is received via this first antenna pattern and this first Frame of being received via this second antenna pattern; And
Repeat above step at any remaining antenna pattern.
10. method as claimed in claim 9 is characterized in that: comprise a signal quality that repeats this first Frame that this receiving step and this step of transmitting received with a signal quality of measuring this first control frame that is received via this first antenna pattern and via this second antenna pattern at each distant station.
11. method as claimed in claim 9 is characterized in that: this first control frame that is received comprises that a request sends message, and this second control frame of being launched comprises a clear to send message.
12. the method for claim 1 is characterized in that: this directional antenna comprises omnidirectional's angle and a plurality of directional angle, and produces antenna database, and it comprises:
Choose one first distant station;
Via omnidirectional's angular emission one first detectable signal of this directional antenna to this first distant station;
The one first probe response signal that measurement is received from this first distant station via this omnidirectional's angle is to respond this first detectable signal;
Via each angle in a plurality of directional angle of this directional antenna, launch corresponding second detectable signal to this first distant station; And
The one second probe response signal that measurement receives from this first distant station via each directional angle is with this corresponding second detectable signal of response.
13. method as claimed in claim 12 is characterized in that: also comprise:
From described a plurality of distant stations, choose a next distant station;
To the step of selected distant station repeat its transmission first and second detectable signals of this next one, and the step of measuring the first and second probe response signals that received from the selected distant station of this next one; And
Repeat above step at any remaining distant station in described a plurality of distant stations.
14. method as claimed in claim 12, it is characterized in that: this first detectable signal comprises that a request sends (RTS) message and this first probe response signal comprises a clear to send (CTS) message, and wherein this second detectable signal comprises that a RTS message and this second probe response signal comprise a CTS message.
15. the method for claim 1 is characterized in that: this access point is based on an IEEE 802.11 standards and one of them the standard running of an IEEE 802.16 standards.
16. the method for claim 1 is characterized in that: this directional antenna comprises at least one active block and a plurality of passive block.
17. an access point that is used for WLAN (WLAN), it comprises:
One directed antenna, it includes a plurality of antenna patterns; And
One controller, it is connected in this directional antenna, and in order to control this directional antenna, this controller is communicated by letter with a plurality of distant stations by carrying out the following step:
By relevant with each distant station corresponding to the corresponding signal quality that records of one of described a plurality of antenna patterns, producing an antenna database,
For each distant station serves as that a preferable antenna pattern is judged on the basis with this antenna database,
The corresponding preferable antenna pattern of choosing a distant station and communicating with, and
Based on this antenna database and with before this selected distant station is communicated by letter, be not selected the relevant corresponding signal quality of distant station by relatively more relevant measures signal quality and with using the described of identical preferable antenna pattern with the preferable antenna pattern of this selected distant station, thus judge whether have any distant station that is not selected also do not know this selected distant station with whether take place via the reality of communicating by letter between the access point of the preferable antenna pattern of this correspondence.
18. access point as claimed in claim 17 is characterized in that: this directional antenna comprises at least one active block and a plurality of passive block.
19. access point as claimed in claim 17 is characterized in that: described measures signal quality comprise a received signal intensity reading, one carrier wave-interference ratio, one energy-bit than and a signal to noise ratio at least one of them.
20. access point as claimed in claim 17, wherein said a plurality of antenna patterns comprise an omnidirectional antenna pattern; And wherein judging at least one described distant station that is not selected when this controller can also not know in the actual generation of described communication, then this controller sends a clear to send message to described a plurality of distant stations via this omni-directional antenna diagram case, and this clear to send message has a not use address that does not correspond to arbitrary station in described a plurality of distant station.
21. access point as claimed in claim 17 is characterized in that: described a plurality of antenna patterns comprise an omnidirectional antenna pattern; And wherein judge and describedly be not selected in the middle of the distant station at least one standing in and do not know that also then this controller carries out the following step in the actual generation of described communication when this controller:
In a forward link, launch a request via this omnidirectional antenna pattern and send message to described a plurality of distant stations;
Receive a clear to send message from this selected distant station;
Launch a Frame to selecting distant station; And
Receive one from this selected distant station and confirm message.
22. access point as claimed in claim 17 is characterized in that: described a plurality of antenna patterns comprise an omnidirectional antenna pattern; And wherein judge and describedly be not selected in the distant station at least one standing in and do not know that also then this controller carries out the following step in the actual generation of described communication when this controller:
In a backward chaining, receive a request and send message from this selected distant station;
Launch a clear to send message to selecting distant station;
Receive a Frame from this selected distant station; And
Emission one confirms that message is to selecting distant station.
23. access point as claimed in claim 22, it is characterized in that: this controller repeats this receiving step and this step of transmitting at each distant station, reaches a signal quality of second control frame that is received via this second antenna pattern with a signal quality of measuring first control frame that is received via this first antenna pattern.
24. access point as claimed in claim 22, this first control frame that is wherein received comprises this clear to send message, and this second control frame that is received comprises this affirmation message.
25. access point as claimed in claim 17 is characterized in that: this directional antenna comprises omnidirectional's angle and a plurality of directional angle; And wherein this controller carries out the following step to produce antenna database:
Choose one first distant station;
Via omnidirectional's angle of this directional antenna, launch one first detectable signal to this first distant station;
The one first probe response signal that measurement is received from this first distant station via this omnidirectional's angle is to respond this first detectable signal;
Via each angular emission one corresponding second detectable signal in the middle of a plurality of directional angle of this directional antenna to this first distant station; And
The one second probe response signal that measurement is received from this first distant station via each directional angle is with this corresponding second detectable signal of response.
26. access point as claimed in claim 25 is characterized in that: this controller more carries out the following step:
From described a plurality of distant stations, choose a next distant station;
To the step of selected distant station repeat its transmission first and second detectable signals of this next one and the step of measuring the first and second probe response signals that received from the selected distant station of this next one; And
Repeat above step at each remaining in described a plurality of distant stations distant station.
27. access point as claimed in claim 25, it is characterized in that: this first detectable signal comprises that a request sends (RTS) message and this first probe response signal comprises a clear to send (CTS) message, and wherein this second detectable signal comprises that a RTS message and this second probe response signal comprise a CTS message.
28. access point as claimed in claim 17 is characterized in that: this controller is based on an IEEE802.11 standard and one of them the standard running of an IEEE 802.16 standards.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US47970103P | 2003-06-19 | 2003-06-19 | |
| US60/479,701 | 2003-06-19 | ||
| US10/870,702 | 2004-06-17 |
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| CN1809964A CN1809964A (en) | 2006-07-26 |
| CN100438348C true CN100438348C (en) | 2008-11-26 |
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| CNB2004800171353A Expired - Fee Related CN100438348C (en) | 2003-06-19 | 2004-06-18 | Antenna steering and hidden node recognition for an access point |
| CNB2004800169921A Expired - Fee Related CN100481743C (en) | 2003-06-19 | 2004-06-18 | Access point of wireless local network, and operation method thereof |
| CNA2004800169940A Pending CN1809976A (en) | 2003-06-19 | 2004-06-18 | Antenna steering for an access point based upon spatial diversity |
| CNA2004800171796A Pending CN1817053A (en) | 2003-06-19 | 2004-06-18 | Antenna steering for an access point based upon probe signals |
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| CNB2004800169921A Expired - Fee Related CN100481743C (en) | 2003-06-19 | 2004-06-18 | Access point of wireless local network, and operation method thereof |
| CNA2004800169940A Pending CN1809976A (en) | 2003-06-19 | 2004-06-18 | Antenna steering for an access point based upon spatial diversity |
| CNA2004800171796A Pending CN1817053A (en) | 2003-06-19 | 2004-06-18 | Antenna steering for an access point based upon probe signals |
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| US7769348B2 (en) * | 2006-11-24 | 2010-08-03 | Sony Ericsson Mobile Communications Ab | Ad-hoc connectivity system and method |
| DE602007013686D1 (en) * | 2007-02-07 | 2011-05-19 | Sony Deutschland Gmbh | A method of transmitting a signal in a wireless communication system and communication system |
| EP2111068B1 (en) * | 2008-04-14 | 2014-01-01 | Alcatel Lucent | A picocell base station for wireless telecommunications providing radio coverage lobes as well as a method of identifying which subset of the lobes covers a user terminal |
| CN103346826B (en) * | 2013-06-27 | 2016-06-29 | 福建星网锐捷网络有限公司 | The system of selection of smart antenna and access point |
| US10218478B2 (en) * | 2014-08-24 | 2019-02-26 | Lg Electronics Inc. | Method for determining weight for beamforming in wireless communication system and apparatus therefor |
| CN105142179B (en) * | 2015-06-12 | 2021-04-06 | 中兴通讯股份有限公司 | Wireless local area network access method and wireless access point |
| CN111525281B (en) * | 2020-04-07 | 2021-09-10 | 普联技术有限公司 | Intelligent antenna device |
| CN113259923B (en) * | 2021-07-05 | 2021-09-24 | 军事科学院系统工程研究院网络信息研究所 | Directional beam detection method, tracking method, detection system and storage medium |
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| US20020051430A1 (en) * | 2000-10-31 | 2002-05-02 | Hideo Kasami | Wireless communication system, weight control apparatus, and weight vector generation method |
| EP1315335A1 (en) * | 2001-11-19 | 2003-05-28 | AT&T Corp. | Adaptive MAC packets fragmentation and rate selection for 802.11 wireless networks |
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2004
- 2004-06-18 CN CNB2004800171353A patent/CN100438348C/en not_active Expired - Fee Related
- 2004-06-18 CN CNB2004800169921A patent/CN100481743C/en not_active Expired - Fee Related
- 2004-06-18 CN CNA2004800169940A patent/CN1809976A/en active Pending
- 2004-06-18 CN CNA2004800171796A patent/CN1817053A/en active Pending
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20020051430A1 (en) * | 2000-10-31 | 2002-05-02 | Hideo Kasami | Wireless communication system, weight control apparatus, and weight vector generation method |
| EP1315335A1 (en) * | 2001-11-19 | 2003-05-28 | AT&T Corp. | Adaptive MAC packets fragmentation and rate selection for 802.11 wireless networks |
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| CN1809964A (en) | 2006-07-26 |
| CN100481743C (en) | 2009-04-22 |
| CN1817053A (en) | 2006-08-09 |
| CN1809976A (en) | 2006-07-26 |
| CN1809968A (en) | 2006-07-26 |
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