HK1167048A - Measurement support for a smart antenna in a wireless communication system - Google Patents

Abstract

A method for taking measurements with a smart antenna in a wireless communication system having a plurality of STAs begins by sending a measurement request from a first STA to a second STA. At least two measurement packets are transmitted from the second STA to the first STA. Each measurement packet is received at the first STA using a different antenna beam. The first STA performs measurements on each measurement packet and selects an antenna beam direction based on the measurement results.

Description

Smart antenna measurement support in wireless communication systems

The patent application of the invention is a divisional application of an invention patent application with the international application number of PCT/US2005/031655, the international application date of 9/7 in 2005, the application number of 200580030246.2 in the Chinese national stage and the name of intelligent antenna measurement support in a wireless communication system.

Technical Field

The present invention relates to a wireless communication system, and more particularly, to an apparatus and method for efficient measurement using a smart antenna in the wireless communication system.

Background

In a Wireless Local Area Network (WLAN), Access Points (APs) and Stations (STAs) may be equipped with smart antennas, for example, a multiple beam/directional antenna system. Both the AP and the STA need to perform measurements to determine the best beam to transmit to or receive from another STA, STAs with multiple beams typically perform scanning on different beams in order to estimate which is the best beam to serve them. Scanning performed by APs and/or STAs may be performed using dummy packets, data packets, 802.11 Acknowledgements (ACKs), or broadcast packets, and measurements may need to be updated frequently.

At the AP, the beam switching algorithm uses packets from the STA for antenna measurements, and the best beam (based on received packet measurements, e.g., a received power or signal-to-interference-plus-noise ratio (SINR)) is then used to transmit packets to the STA. At the STA, current beam switching algorithms may use data packets or beacons to determine the correct reception and transmit antenna/beam for the AP. This antenna measurement is not very efficient because it is time consuming to obtain enough measurements to determine the correct beam for each STA.

Another problem with this beam selection method is in the beam selection aspect for both reception and transmission, which is based on measurements made on the received packets. In practice, however, the best beam for transmission may not be the same as the best beam for reception (especially in frequency division duplex systems).

Disclosure of Invention

A method for performing measurements with a smart antenna in a wireless communication system having a plurality of STAs. First, a first STA sends a measurement request to a second STA, and at least two measurement packets are transmitted from the second STA to the first STA. Each measurement packet is received at the first STA using a different antenna beam. The first STA performs measurements on each of the measurement packets and selects an antenna beam direction based on the measurement results.

A method for performing measurements with a smart antenna in a wireless communication system having a plurality of STAs. First, a first STA sends a measurement request to a second STA, and at least two measurement packets are transmitted from the second STA to the first STA. Each measurement packet is transmitted using a different antenna beam at the first STA. The second STA receives each of the measurement packets and performs measurements on each of the measurement packets. The second STA generates a measurement report according to the measurement result and sends the measurement report to the first STA. The first STA selects an antenna beam direction based on the measurement report.

A system for performing measurements with a smart antenna in a wireless communication system includes a first STA and a second STA. The first STA includes a first transmitter/receiver; a first antenna connected to the first transmitter/receiver; a measurement packet request device connected to the first transmitter/receiver; a measurement packet analysis device connected to the first transmitter/receiver; and a beam changing device connected to the first transmitter/receiver and the measurement packet analyzing device. The second STA includes a second transmitter/receiver; a second antenna connected to the second transmitter/receiver; a measurement packet request receiving device connected to the second transmitter/receiver; and a measurement packet transmitting device connected to the second transmitter/receiver and the measurement packet request receiving device.

A system for performing measurements with a smart antenna in a wireless communication system includes a first STA and a second STA. The first STA includes a first transmitter/receiver; a first antenna connected to the first transmitter/receiver; a measurement packet request device connected to the first transmitter/receiver; a measurement packet transmission device connected to the first transmitter and the measurement packet request device; beam changing means connected to the first transmitter/receiver and the measurement packet transmitting means; and a measurement report analyzing device connected to the first transmitter/receiver and the beam changing device. The second STA includes a second transmitter/receiver; a second antenna connected to the second transmitter/receiver; a measurement packet request receiving device connected to the second transmitter/receiver; and a measurement report generating device connected to the second transmitter/receiver and the measurement packet analyzing device.

Drawings

The invention will be understood in more detail from the following description of preferred embodiments, given as examples, with reference to the accompanying drawings, in which:

FIG. 1 is a schematic diagram of a measurement request packet;

FIG. 2 is a schematic diagram of a measurement packet;

FIG. 3 is a diagram of a measurement report packet;

FIG. 4 is a flow chart of a method of performing antenna measurements;

FIG. 5 is a signal diagram illustrating the method of FIG. 4;

FIG. 6 is a flow chart of a second method of performing antenna measurements;

FIG. 7 is a signal diagram illustrating the method of FIG. 6;

FIG. 8 is a diagram illustrating a Physical Layer Convergence Protocol (PLCP) frame format; and

fig. 9 is a schematic diagram of a system for communicating measurement information according to the methods shown in fig. 4 and 6.

Detailed Description

Hereafter, the terminology "Station (STA)" is used to include, but is not limited to, a wireless transmit/receive unit, a user equipment, a fixed or mobile subscriber unit, a pager, or any other type of device capable of operating in a wireless environment. When referred to hereafter, the terminology "Access Point (AP)" includes but is not limited to a station, a node B, a station controller, or any other type of interfacing device in a wireless environment.

The present invention not only solves the problem of measurement support for smart antennas, but can be implemented in APs, non-AP STAs, or both. The present invention provides a signaling mechanism to obtain Received Signal Strength Indicator (RSSI) or SINR measurements for each transmit or receive antenna between two stations, and also provides a mechanism to correctly update the reception measurements between scans.

The present invention uses an action frame for antenna measurements, thereby creating a new class of action frames, which is called "antenna measurements". The action frame category includes action fields for a measurement request packet, measurement response packet, and dummy measurement packet, which are currently defined in WLAN standards (i.e., 802.11k, 802.11 e). The measurement packet of the present invention may also be part of a separate control packet or management packet.

Fig. 1 shows a measurement request packet 100 according to the present invention, the measurement request packet 100 comprising fields for the number of transmit or receive packets 102, transmit antenna information 104, request form 106, and measurement report request 108. The number of transmitted or received packets 102 is selected based on parameters such as fading environment and time, and in one embodiment, a preferred value is 10 packets per antenna. The transmit antenna information 104 includes antenna beam identification or any other information that may be used to identify an antenna or a group of antennas. Two possible request forms 106 will be explained below with reference to fig. 4 and 6, however, it is noted that there are many possible ways to send the measurements indicated in the request form field 106 and obtain the response. The measurement report request field 108 includes SNR measurement parameters and RSS measurement parameters.

Fig. 2 shows a measurement packet 200 according to the invention, the measurement packet 200 comprising antenna identification information 202 and a current packet sequence number 204. The antenna identification information 202 includes antenna beam identification or any information that may be used to identify an antenna or a group of antennas.

Fig. 3 shows a measurement report packet 300 according to the present invention, the measurement report packet 300 comprising sequence information 302 (the packet's sequence number), antenna information 304 (i.e., antenna identification information), a measured RSSI value 306, and a measured SNR value 308.

Measurement requests and responses may be initiated by a STA or AP, and measurement request packets 100 and measurement response packets 300 may be sent at any time while the STA is connected to the AP, and the STA may be allowed to use these techniques to measure signals from or sent to each antenna prior to association with the AP.

Fig. 4 is a flow chart of a method 400 for measuring packet exchanges between two STAs 1 and 2 according to a first embodiment of the present invention. The method 400 begins by STA1 sending a measurement request packet to STA2 (step 402). STA2 receives the measurement request packet (step 404) and sends an ACK to STA1 (step 406). STA2 then transmits a measurement packet to STA1 (step 408). STA1 receives the measurement packet and measures the RSSI and/or SNR of the measurement packet (step 410). A determination is made if all packets specified in the measurement request packet have been transmitted.

If all packets have not been transmitted, the STA1 will change its receive beam (step 414). STA2 waits for a short interframe space (SIFS) before transmitting the next packet (step 408) (step 416). In a preferred embodiment, the STA2 waits for SIFS, however, the wait time may vary and may be more or less than the SIFS. The variation in latency is related to the length of time required to switch antenna beams, the accuracy of system blockages, and any other particular implementation that is time dependent. If all packets have been transmitted (step 412), the STA1 selects the transmission beam based on all measured RSSI and/or SN R values (step 418), and the method then terminates (step 420).

Fig. 5 is a signal diagram of a method 400 illustrating the exchange of packets between STA 1502 and STA 2504. The STA 1502 sends a measurement request packet 506 to the STA 2504. STA2504 waits SIFS 508 before sending an ACK 510 in response to measurement request packet 506. The STA2504 then continuously transmits multiple measurement packets 512₁…512_nEach measurement packet 512 is separated by SIFS 514. During the SIFS, the STA 1502 changes its receive beam such that each packet 512₁…512_nAre received on different beams. The STA 1502 then uses the received signal strength of each packet 502 to select the correct beam.

Fig. 6 is a flow chart of a method 600 for measuring packet exchanges between two STAs 1 and 2, according to a second embodiment of the present invention. The method 600 begins by sending a measurement request packet to STA2 (step 602). STA2 receives the measurement request packet (step 604) and sends an ACK to STA1 (step 606). STA1 sends a measurement request from the beam (step 608). STA2 receives the measurement packet and measures the RSSI and/or SNR of the packet (step 610). A determination is made whether all measurement packets specified by the measurement request packet have been transmitted (step 612). If all measurement packets have not been transmitted, the STA1 changes the transmission beam (step 614), waits for a SIFS (step 616), and sends a packet from the new beam (step 608). In a preferred embodiment, the STA2 waits for SIFS, however, the wait time may vary and may be more or less than the SIFS. The variation in latency is related to the length of time required to switch antenna beams, the accuracy of system blockages, and any other particular implementation that is time dependent.

If all packets have been transmitted (step 612), the STA2 will generate a measurement report based on all received measurement packets (step 620). STA2 sends the measurement report to STA1 (step 622) and STA1 sends an ACK for the measurement report to STA2 (step 624). STA1 selects a transmission beam based on the measurement report (step 626), with the method terminating thereafter (step 628).

Fig. 7 is a signal diagram of a method 600 illustrating the exchange of packets between STA1702 and STA 2704. STA1702 sends a measurement request packet 706 to STA 2704. The STA2704 waits for SIFS 708 before sending an ACK 710 in response to the measurement request packet 706. STA1702 may wait for SIFS 712 before sending measurement packet 7141 … 714-n from the beam to STA 2704. Each measurement packet 714 is sent on a different beam and the STA1702 waits for the SIFS 716 before sending the measurement packet 714 on another beam. The STA2704 receives the measurement packet 714 and measures each of the packets. After all measurement packets are received by the STA2704, the STA2704 generates a measurement report packet 718 and sends it to the STA 1702. The STA1702 then sends an ACK to the STA2704 upon receipt of the measurement report packet 718. The STA1702 then selects a beam direction based on the measurement report packet 718.

The measurement request and report information may be carried on data packets, management packets, or control packets. The phy layer signaling may be sent on different beams, and the signaling may be sent such that it identifies the different beams through the same phy layer signal (e.g., preamble) or beam information, and these measurement signals may be sent in packets (without waiting for SIFS).

The invention can also passively measure to update the received signal strength, which may vary from transmitter to transmitter with switching beams or different technologies. In the absence of any notification about the antennas used by the transmitter node, the receiver may eventually make an incorrect decision on reception (or transmission) on the correct beam. The transmission packets include beam identification or different method indications that may be used by the receiver to update the reception measurement information.

The transmit antenna information is sent immediately after a Physical Layer Convergence Protocol (PLCP) header or in a Medium Access Control (MAC) header. The information may be a predefined signal pattern to indicate omni-directional beam or antenna beam identification, which may also be used to indicate different technologies, if any.

Fig. 8 is a diagram illustrating a PLCP frame format 800 according to the present invention. PLCP frame 800 includes a preamble 802, a signal field 804, a Header Error Check (HEC)806, and a physical layer service data unit (PSDU) 810. The present invention adds a new field to the PLCP frame 800, i.e., a transmit/receive antenna identification 808. Downward compatibility is maintained by adding transmit antenna information after the PLCP header, and an additional information field may be added to the MAC header to indicate transmit antenna identification.

The present invention provides an efficient method to measure the signal strength to/from a beam or directional antenna. The current 802.11 standard does not define methods for antenna measurement, the use of dummy packets or beacons is highly inefficient and time consuming, and it limits the use of directional antennas in fading environments and roaming. The present invention allows STAs to transmit and receive using different beams.

Fig. 9 is a schematic diagram of a system 900 configured to propagate measurement information in accordance with the methods 400 and 600 described above with reference to fig. 4 and 6, respectively. The system 900 includes a first STA (STA1)902 and a second STA (STA2) 904. Two separate STAs shown in system 900 are for discussion purposes, and each STA may be constructed with all of the components shown.

The first STA 902 includes a measurement packet request device 910 coupled to a transmitter/receiver 912 coupled to an antenna 914. A measurement packet transmitting device 916 is connected to the measurement packet requesting device 910 and the transmitter/receiver 912. A measurement packet analysis device 918 is connected to the transmitter/receiver 912. A beam changing device 920 is connected to the transmitter/receiver 912, the measurement packet transmitting device 916, and the measurement packet analyzing device 918. A measurement report analysis device 922 is connected to the transmitter/receiver 912 and the beam change device 920.

The second STA 904 includes an antenna 930 connected to a transmitter/receiver 932. A measurement packet request receiving device 934 is connected to the transmitter/receiver 932. A measurement packet transmitter 936 is connected to the transmitter/receiver 932 and the measurement packet request receiver 934. A measurement packet analysis device 938 is connected to the transmitter/receiver 932. Measurement report generation means 940 is connected to the transmitter/receiver 932 and the measurement packet analysis means 938.

The system 900 is configured to operate as follows when implementing the method 400. The measurement packet request device 910 generates a measurement packet request that is sent to the transmitter/receiver 912 for transmission to the second STA 904. The transmitter/receiver 932 receives the measurement packet request and forwards it to the measurement packet request receiving device 934. The measurement packet request receiving device 934 generates an ACK, which is sent to the first STA 902.

After sending the ACK, the measurement packet request receiving device 934 sends a signal to the measurement packet transmitting device 936 to begin sending measurement packets to the first STA 902. When a measurement packet is received at the first STA 902, the transmitter/receiver 912 forwards the measurement packet to the measurement packet analysis device 918, where measurements of RSSI and/or SNR of the measurement packet are made. If all requested measurement packets have not been received, the measurement packet analysis device 918 signals the beam change device 920 to change the receive beam of the first STA 902 to receive additional measurement packets.

If all the requested measurement packets have been received, the measurement packet analysis device selects the appropriate transmission beam based on previous measurements, and then transmits the beam change device 920 for a selected transmission beam.

When implementing the method 600, the system 900 is configured to operate as follows. The measurement packet request device 910 generates a measurement packet request that is sent to the transmitter/receiver 912 for transmission to the second STA 904. The transmitter/receiver 932 receives the measurement packet request and forwards it to the measurement packet request receiving device 934. The measurement packet request receiving device 934 generates an ACK, which is sent to the first STA 902.

Immediately after receiving the ACK, the measurement packet requesting device 910 signals the measurement packet transmitting device 916 to begin transmitting measurement packets to the second STA 904. After measurement packet reception, the transmitter/receiver 932 forwards the measurement packet to the measurement packet analysis device 938, where it is measured. If all the requested measurement packets have not been transmitted, the measurement packet transmitting means 916 signals the beam changing means 918 to change the transmission beam before sending the next measurement packet.

If all requested measurement packets have been transmitted, the measurement report generating device 940 generates a measurement report, which is sent to the first STA 902. The measurement report is forwarded to the measurement report analysis device 922, which selects a transmission beam for the first STA 902 according to the measurement report. The measurement report analysis device 922 sends the selected beam to the beam change device 920 to change the transmission beam of the first STA 902.

Examples

1. A method for performing measurements with a smart antenna in a wireless communication system having a plurality of STAs, comprising the steps of: sending a measurement request from the first STA to the second STA; transmitting, by the second STA, at least two measurement packets to the first STA sequentially or simultaneously; receiving each of the measurement packets at the first STA using a different antenna beam; performing measurements on the first STA for each of the measurement packets; and selecting an antenna beam direction on the first STA according to the measurement result.

2. The method of embodiment 1 wherein the measurement request includes a plurality of measurement packets to be transmitted.

3. The method of any preceding embodiment, wherein the transmitting step comprises: waiting for an interframe space between transmission measurement packets.

4. The method of embodiment 3 wherein the interframe space is one of a short interframe space (SIFS), less than a SIFS, and more than a SIFS.

5. The method of any preceding embodiment, wherein the performing step comprises: the Received Signal Strength Indicator (RSSI) of each of the measurement packets is measured.

6. The method of embodiment 5, wherein the selecting step comprises: a transmission beam direction is selected based on the measured RSSI value.

7. The method as in any preceding embodiment 1-4, wherein the performing step comprises: the signal-to-noise ratio (SNR) per the measurement packet is measured.

8. The method of embodiment 7, wherein the selecting step comprises: a transmission beam direction is selected based on the measured SNR value.

9. The method as in any preceding embodiment 1-4, wherein the performing step comprises: the Received Signal Strength Indicator (RSSI) and signal to noise ratio (SNR) of each of the measurement packets are measured.

10. The method of embodiment 9 wherein a transmit beam direction is selected based on the measured RSSI and SNR values.

11. The method of any of the preceding embodiments, further comprising: an acknowledgement is sent by the second STA to the first STA immediately after the measurement request.

12. The method of any of the preceding embodiments, further comprising: after receiving a measurement packet, the receive beam of the antenna on the first STA is changed to a different beam, whereby the antenna on the first STA uses a different beam to receive the next measurement packet.

13. A method for performing measurements with a smart antenna in a wireless communication system having a plurality of STAs, comprising the steps of: sending, by the first STA, a measurement request to the second STA; transmitting, by the first STA, at least two measurement packets, consecutively or simultaneously, to the second STA, each of the transmission packets being transmitted using a different antenna beam; receiving each of the measurement packets at the second STA; performing measurements on the second STA for each of the measurement packets; generating a measurement report at the second STA according to the measurement result; sending the measurement report from the second STA to the first STA; and selecting an antenna beam direction at the first STA according to the measurement report.

14. The method of embodiment 13 wherein the measurement request includes a plurality of measurement packets to be transmitted.

15. The method of any preceding embodiment, wherein the transmitting step comprises: waiting for an interframe space between transmission measurement packets.

16. The method of embodiment 15, wherein the interframe space is one of short interframe space (SIFS), less than a SIFS, and more than a SIFS.

17. The method of any of the preceding embodiments, further comprising: an acknowledgement is sent by the second STA to the first STA immediately after the measurement request.

18. The method of any of the preceding embodiments, further comprising: after receiving a measurement packet, the receive beam of the antenna on the first STA is changed to a different beam, whereby the antenna on the first STA uses a different beam to receive the next measurement packet.

19. The method of any of the preceding embodiments, further comprising: an acknowledgement is sent by the first STA to the second STA immediately after the measurement request.

20. A system for performing measurements with a smart antenna in a wireless communication system includes a first STA and a second STA. The first STA includes a first transmitter/receiver; a first antenna connected to the first transmitter/receiver; a measurement packet request device connected to the first transmitter/receiver; a measurement packet analysis device connected to the first transmitter/receiver; and beam changing means connected to the first transmitter/receiver and the measurement packet analyzing means. The second STA includes a second transmitter/receiver; a second antenna connected to the second transmitter/receiver; and a measurement packet transmitting device connected to the second transmitter/receiver and the measurement packet request receiving device.

21. The system of embodiment 20 wherein the measurement packet request device is configured to send a measurement packet request and receive an acknowledgement from the second station that received the measurement packet request.

22. The system as in embodiments 20 or 21 wherein the measurement packet analysis device is configured to receive measurement packets from the second station, measure the measurement packets, and send a selected beam to the beam change device.

23. A system as in any of embodiments 20-22 wherein the measurement packet request receiving device is configured to receive a measurement packet request from the first station, send an acknowledgement to the first station that receives the measurement packet request, and send the measurement packet request to the measurement packet transmitting device for sending a measurement packet to the first station.

24. A system as in any of embodiments 20-23 wherein the measurement packet transmission device is configured to send measurement packets to the first station.

25. A system for performing measurements with a smart antenna in a wireless communication system includes a first STA and a second STA. The first STA includes a first transmitter/receiver; a first antenna connected to the first transmitter/receiver; a measurement packet request device connected to the first transmitter/receiver; a measurement packet transmission device connected to the first transmitter and the measurement packet request device; beam changing means connected to the first transmitter/receiver and the measurement packet transmitting means; and a measurement report analyzing device connected to the first transmitter/receiver and the beam changing device. The second STA includes a second transmitter/receiver; a second antenna connected to the second transmitter/receiver; a measurement packet request receiving device connected to the second transmitter/receiver; and a measurement report generating device connected to the second transmitter/receiver and the measurement packet analyzing device.

26. The system of embodiment 25 wherein the measurement packet request device is configured to send a measurement packet request and receive an acknowledgement from the second station receiving the measurement packet request.

27. The system as in embodiments 25 or 26 wherein the measurement packet transmitting device is configured to send the measurement packet to the second station.

28. A system as in any of embodiments 25-27 wherein the measurement packet transmission device is configured to send a signal to the beam change device to change the transmission beam of the first station.

29. A system as in embodiments 25-28 wherein the measurement report analyzing device is configured to receive a measurement report from the second station, to select a transmission beam for the first station based on the measurement report, and to send a signal to the beam changing device to change the transmission beam of the first station to the selected beam.

30. A system as in embodiments 25-29 wherein the measurement packet request receiving device is configured to receive a measurement packet request from the first station and send an acknowledgement to the first station that received the measurement packet request.

31. A system as in embodiments 25-30 wherein the measurement packet analysis device is configured to receive the measurement packet from the first station, measure the measurement packet, and forward the measurement to the measurement report generation device.

32. A system as in embodiments 25-31 wherein the measurement report generating device is configured to receive the measurements from the measurement packet analysis device and generate a measurement report to the first station.

Although the features and elements of the present invention are described in the embodiments in particular combinations, each feature or element can be used alone without the other features and elements of the preferred embodiments or in various combinations with or without other features and elements of the present invention. While the invention has been described in terms of preferred embodiments, other variations which do not depart from the gist of the invention will be apparent to those skilled in the art. The foregoing description is for the purpose of illustration and is not intended to limit the particular invention in any way.

Claims (47)

1. A method for beam selection in wireless communications, the method comprising:

receiving a plurality of measurement packets using different beams for each packet;

measuring each of the plurality of measurement packets;

generating a measurement report;

selecting a beam based on the measurements of each of the plurality of measurement packets; and

transmitting the measurement report using the selected beam.

2. The method of claim 1, wherein each of the plurality of measurement packets comprises a field indicating a number of received packets.

3. The method of claim 2, wherein the number of received packets is a number of the plurality of measurement packets.

4. The method of claim 1, wherein receiving the plurality of measurement packets comprises waiting for an interframe space between receiving each of the plurality of measurement packets.

5. The method of claim 4, wherein the interframe space is the short interframe space (SIFS).

6. The method of claim 1, wherein the measuring each of the plurality of measurement packets comprises measuring a Received Signal Strength Indicator (RSSI) of each of the plurality of measurement packets.

7. The method of claim 6, wherein the selecting the beam comprises selecting a transmission beam based on a measured Received Signal Strength Indicator (RSSI) of each of the plurality of measurement packets.

8. The method of claim 1, wherein the measuring each of the plurality of measurement packets comprises measuring a signal-to-noise ratio (SNR) of each of the plurality of measurement packets.

9. The method of claim 8, wherein the selecting the beam comprises selecting a transmission beam based on a measured signal-to-noise ratio (SNR) of each of the plurality of measurement packets.

10. The method of claim 1, wherein the measuring each of the plurality of measurement packets comprises measuring a Received Signal Strength Indicator (RSSI) and a signal to noise ratio (SNR) of each of the plurality of measurement packets.

11. The method of claim 10, wherein the selecting the beam comprises selecting a transmission beam based on the measured RSSI and the measured SNR for each of the plurality of measurement packets.

12. The method of claim 1, further comprising:

before data transmission, a beam selection process is started.

13. The method of claim 12, further comprising:

receiving an acknowledgement in response to the starting beam selection process.

14. The method of claim 12, wherein initiating beam selection comprises transmitting a measurement request.

15. The method of claim 12, wherein starting beam selection is based on antenna identification.

16. The method of claim 12, wherein the starting the beam selection process comprises requesting a number of measurement packets.

17. The method of claim 1, wherein each of the plurality of measurement packets comprises transmit antenna information, wherein the transmit antenna information comprises an antenna beam identification or information identifying an antenna.

18. A method for beam selection in wireless communications, the method comprising:

transmitting a plurality of measurement packets;

receiving a measurement report from a Station (STA), wherein the measurement report is based on at least one of the plurality of measurement packets; and

selecting a beam based on the measurement report.

19. The method of claim 18, wherein each of the plurality of measurement packets comprises a field indicating a number of received packets.

20. The method of claim 19, wherein the number of received packets is a number of the plurality of measurement packets.

21. The method of claim 18, further comprising:

the beam selection process starts by requesting the number of measurement packets to be transmitted.

22. The method of claim 21, further comprising:

receiving an acknowledgement in response to the starting beam selection process.

23. The method of claim 18, wherein transmitting the plurality of measurement packets comprises waiting for an interframe space between transmitting each of the plurality of measurement packets.

24. The method of claim 23, wherein the interframe space is the short interframe space SIFS.

25. The method of claim 18, further comprising:

transmitting an acknowledgement upon receiving the measurement report.

26. The method of claim 18, wherein the measurement report comprises a result of the measurement performed on each measurement packet.

27. The method of claim 18, further comprising:

beam selection is started by transmitting a measurement request.

28. The method of claim 27, wherein starting beam selection is based on antenna identification.

29. The method of claim 18, wherein each of the plurality of measurement packets comprises transmit antenna information, wherein the transmit antenna information comprises an antenna beam identification or information identifying an antenna.

30. The method of claim 18 wherein the STA is an Access Point (AP).

31. A station, the station comprising:

an antenna configured for

Receiving a first measurement packet on a first beam;

receiving a second measurement packet on a second beam after the first antenna receives the first measurement packet;

a processor configured to measure each of the two measurement packets; and

a selector configured to select a transmission beam based on the measurement.

32. The station according to claim 31, wherein the first measurement packet and the second measurement packet include a field indicating a number of received packets.

33. The station according to claim 32, wherein the number of received packets is the number of the plurality of measurement packets.

34. The station of claim 31, wherein the antenna is configured to receive the two measurement packets spatially separated by an inter-frame space.

35. The station of claim 31, wherein the antenna is configured to receive the two measurement packets separated by a short interframe space (SIFS).

36. The station according to claim 31, further comprising:

a transmitter configured to start beam selection before data transmission.

37. The station of claim 36, wherein the transmitter is configured to initiate beam selection based on antenna identification.

38. The station of claim 36, wherein the transmitter is configured to initiate beam selection by transmitting a measurement request.

39. The station of claim 31, wherein the first measurement packet or the second measurement packet comprises transmit antenna information, wherein the transmit antenna information comprises an antenna beam identification or information identifying an antenna.

40. A station as defined in claim 31, wherein the station is an access point, AP.

41. A station, the station comprising:

a transmitter configured to transmit a plurality of measurement packets;

a receiver configured to receive a measurement report based on at least one of the plurality of measurement packets; and

a selector configured to select a beam based on the measurement report.

42. The station according to claim 41, wherein each of the plurality of measurement packets includes a field indicating a number of received packets.

43. The station according to claim 42, wherein the number of received packets is the number of the plurality of measurement packets.

44. The station according to claim 41, wherein the transmitter is configured to transmit the plurality of measurement packets separated by inter-frame space.

45. The station according to claim 41, wherein said transmitter is configured for transmitting the plurality of measurement packets separated by a short interframe space (SIFS).

46. The station of claim 41, wherein each of the plurality of measurement packets comprises transmit antenna information, wherein the transmit antenna information comprises an antenna beam identification or information identifying an antenna.

47. A station as defined in claim 41, wherein the station is an Access Point (AP).