Optimum scan for fixed-wireless smart antennas

• US 20030228857A1
• Filed: 06/06/2002
• Published: 12/11/2003
• Est. Priority Date: 06/06/2002
• Status: Abandoned Application

• Current Assignee: Renesas Technology Corporation (Renesas Electronics Corporation)
• Original Assignee: Hitachi, Ltd.
• Inventors: Maeki, Akira
• Application Number:
  US10/163,852
• Publication Number:
  US 20030228857A1
• Time in Patent Office: Days
• US Class Current: 455/278.1
• CPC Class Codes: H01Q 1/246 specially adapted for base stations
• CPC Class Codes: H01Q 3/24 varying the orientation by switching energy from one active radiating element to another, e.g. for beam switching
• CPC Class Codes: H04B 7/0617 for beam forming
• CPC Class Codes: H04B 7/0695 using beam selection
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

Events determine the timing of when to change performance, for example when to scan or when to use a prior stored usually best-performance configuration or just a last configuration, for a smart antenna in a fixed or almost fixed usage like a wireless local area network and a television system. Thereby the system maintains unchanged the parameters, such as those that determine the beam form of the smart antenna until monitoring recognizes one or a combination of more than one of the following conditions or event occurrences; the device communicate with another device for the first time; reboot of the device or the device turns on; the received signal exceeds a predetermined bit error rate (BER); the received signal strength indicator (RSSI) is less than a determined RSSI; the received signal goes below a predetermined signal to noise ratio (SNR); and a user'"'"'s demand. The performance is changed by changing of the communication parameters, for example: the previous measured configuration data to reduce the scan area and reduces the scan time; control of the transmission power of the communicating device to maintain performance or quality; channel selection to minimize collision in the transmission; switching to the another antenna; change the data rate; and change the modulation scheme. Maintaining the communication with another antenna during the scan of one smart antenna is another key point.

Claims

1. A smart antenna system for wireless communication between devices, comprising:

a smart antenna subsystem adapted to be spatially steered and including an antenna array of a plurality of directional antenna elements, and further including a beam former;

a wireless communicator;

a baseband unit;

a performance monitor;

a memory;

a signal processing unit to scan configurations of and form a beam of the antenna subsystem;

said performance monitor measuring a bit error rate (BER) and/or received signal strength indicator (RSSI) and/or SNR; and

said memory having a machine readable media with a machine readable code representative of the measured BER and/or RSSI and/or SNR linked to different past configurations of the smart antenna subsystem.

2. A smart antenna system for wireless communication between devices, comprising:

a smart antenna subsystem unit adapted to be spatially steered and including an antenna array of a plurality of directional antenna elements, and a beam former;

a wireless communicator unit;

a performance monitor;

a memory;

a signal processing unit to scan configurations of and form a beam of the antenna subsystem;

said performance monitor measuring a bit error rate (BER) and/or received signal strength indicator (RSSI) and/or Signal to Noise Ratio (SNR) during normal valid data wireless communication with said smart antenna subsystem;

said memory having a machine readable media with a machine readable code representative of performance reference values for BER and/or RSSI and/or SNR;

said performance monitor comparing the measured BER and/or RSSI and/or SNR with the performance reference values for BER and/or RSSI and/or SNR, respectively, on a substantially continuous basis during communication of valid data and producing a signal when the comparing indicates a predetermined degradation of performance; and

said performance monitor, coupled to at least one of said units, and being responsive to the signal to generate a command to said at least one of said units to change the beam form of said smart antenna subsystem.

3. The smart antenna system of claim 2, wherein:

said wireless communicator unit has a plurality of channels for communication with said smart antenna subsystem, and said change control unit changes operative channels in response to the command.

4. The smart antenna system of claim 2, further including:

another antenna;

an antenna switch selectively coupling one of said smart antenna subsystem and said another antenna to said wireless communicator, and

said antenna switch being responsive to said command to change the antenna to said another antenna to obtain a best-performance making use of spatial diversity and/or polarization diversity.

5. The smart antenna system of claim 2, wherein:

said monitor adjusts transmit power in response to the command to obtain a best-performance.

6. An antenna system for wireless communication between relatively fixed locations, comprising:

a smart antenna subsystem adapted to be spatially steered, including an array of antenna elements and a beam former to scan and shape the beam of the array;

a performance monitor coupled to said signal processor to measure wireless communication performance;

a memory storing a plurality of past configurations of said smart antenna subsystem; and

said monitor commanding said smart antenna subsystem to change to one of said past configurations upon the occurrence of a predetermined event.

7. The system of claim 6, wherein:

the event is a machine originating start event.

8. The system of claim 6, wherein:

said monitor generates the event when communication performance degrades a predetermined amount.

9. A wireless data communication system for a relatively fixed environment, comprising:

a smart antenna subsystem adapted to be spatially steered;

a monitor couple to continuously receive valid data during communication and continuously generate updated performance data; and

said monitor having a comparator generating a beam form change command in response to a comparison of the updated performance data with a predetermined performance reference indicating a predetermined degradation of performance.

10. The system of claim 9, wherein:

said smart antenna subsystem has a plurality of channels for communication and said monitor changes operative channels in response to the command.

11. The system of claim 9, further including:

another antenna;

an antenna switch selectively coupling one of said smart antenna subsystem and said another for system communication; and

said antenna switch being responsive to said command to change the antenna to said another antenna.

12. The system of claim 11, further including:

a scan unit responsive to said command for scanning and optimizing the beam form to get better performance; and

said antenna switch being responsive to the occurrence of both said command and a predetermined amount of the scan to change the antenna to said another antenna to obtain a best-performance making use of spatial diversity and/or polarization diversity.

13. The system of claim 9, further including

a scan unit responsive to said command for scanning and optimizing the beam form to get better performance.

14. The system of claim 9, wherein:

said monitor adjusts power of said smart antenna subsystem in response to the command.

15. A method performed by a machine for wireless communication with a smart antenna system in a relatively fixed environment, comprising the steps of:

performing a start operation for the system; and

in response to said start operation, configuring the smart antenna to a configuration stored into a memory prior to said start operation.

16. The method of claim 15, wherein:

said start operation is a first time wireless communication with a device using another antenna.

17. The method of claim 15, wherein:

said start operation is one of a system boot and reboot.

18. The method of claim 15, further comprising:

scanning the smart antenna; and

wherein said start operation is the start of said step of scanning.

19. The method of claim 18, further comprising:

said scanning successively configuring the smart antenna to each configuration selected from among a plurality of best-performance configurations achieved from prior scans and stored into a memory prior to said step of scanning; and

configuring the smart antenna to the best-performance configuration of said scanning.

20. The method of claim 15, wherein:

said start operation is in response to a human originating user demand event.

21. The method of claim 15, wherein:

said start operation is in response to a machine originating event.

22. A method performed by a machine for wireless communication with a smart antenna system in a relatively fixed environment, comprising the steps of:

wireless communicating valid data with a fixed smart antenna configuration having a beam shape;

monitoring said wireless communicating for a predetermined degradation of performance; and

in response to the predetermined degradation, changing the beam shape of the smart antenna.

23. The method of claim 22, further comprising:

maintaining in storage a plurality of best-performance configurations from past scans of the smart antenna; and

wherein said changing includes configuring the smart antenna according to a selected one of the stored plurality of best-performance configurations.

24. The method of claim 22, wherein:

said changing includes scanning the smart antenna until achieving one configuration of a best performance and a performance not having the predetermined degradation.

25. The method of claim 22, further comprising:

said scanning successively configuring the smart antenna to each configuration selected from among a plurality of best-performance configurations achieved from prior scans and stored into a memory prior to said step of scanning; and

configuring the smart antenna to the best-performance configuration of said scanning.

26. The method of claim, 25 further comprising:

after said step of scanning, configuring the antenna to the best performance configuration of said step of scanning and returning to said step of monitoring, without interrupting said communicating.

27. The method of claim, 26 further comprising:

after said step of scanning, changing the coding of said step of wireless communicating to maintain a set bit error rate (BER).

28. The method of claim 22, wherein

said step of monitoring includes measuring the bit error rate (BER) and a signal to noise ratio (SNR), and comparing the BER and SNR to respective predetermined data for determining the predetermined degradation.

29. The method of claim 22, wherein:

said changing includes switching said wireless communicating step to another antenna.

30. The method of claim 22, wherein:

said changing includes switching the channel of said wireless communicating step.

31. The method of claim 22, wherein:

said changing includes adjusting power of said wireless communicating step.

32. The method of claim 22, wherein:

said changing includes configuring the smart antenna to a configuration stored into a memory prior to said step of changing.

33. The method of claim 22, wherein:

said changing includes configuring the smart antenna to a configuration selected from among a plurality of best-performance configurations achieved from prior scans and stored into a memory prior to said step of changing.