Method of and device for antennae diversity switching

• US 20040266374A1
• Filed: 06/30/2003
• Published: 12/30/2004
• Est. Priority Date: 06/30/2003
• Status: Active Grant

• Current Assignee: Zarbana Digital Fund LLC (Intellectual Ventures LLC)
• Original Assignee: Seven Generations Energy Ltd.
• Inventors: Saed, Aryan, Guillemette, Phil
• Granted Patent: US 7,359,692 B2
• Time in Patent Office: Days
• US Class Current: 455/134
• CPC Class Codes: H04B 7/0811 during preamble or gap period
• CPC Class Codes: H04B 7/0814 based on current reception conditions, e.g. switching to different antenna when signal level is below threshold

Abstract

The invention relates to the field of wireless communications, more particularly to a method of and device for switching between antennae in communication with a diversity receiver, each of the antennae receiving signals transmitted from a single source. A packet from a transmitter is received by respective antenna communicating with a diversity receiver. The signal strength of the preamble of the packet received in a first antenna is sampled. If the signal strength is of sufficient magnitude to affect reliable reception, the associated antenna is selected for the duration of the packet transmission. If the signal strength is below a predetermined threshold the signal strength of the preamble of the packet received in a second antenna is sampled and compared to the sample associated with the first antenna. If the magnitude of the second sample is greater, the signal associated with the second antenna is selected. To determine the signal strength, the arithmetic average of the signal power over a given period of the preamble is used.

Claims

1. In a wireless communication system, a method of selecting an antenna from at least two antennae on a per packet basis, the method comprising:

(a) receiving, at each of said at least two antennae communicating with a diversity receiver, a data packet transmitted over a wireless communication link, said data packet comprising at least a preamble and said preamble having a signal strength associated therewith;

(b) determining said data packet preamble signal strength associated with a first antenna; and

(c) selecting said first antenna if the determined signal strength exceeds a predetermined threshold.

2. The method of claim 1 further comprising the steps of:

(a) determining said data packet preamble signal strength associated with a second antenna, if

said data packet preamble signal strength associated with said first antenna does not exceed the predetermined threshold;

(b) comparing said data packet preamble signal strength associated with said second antenna with said data packet preamble signal strength associated with said first antenna; and

(c) selecting said second antenna if said data packet preamble signal strength associated with said second antenna is greater than said data packet preamble signal strength associated with said first antenna.

3. The method of claim 2 wherein said step of determining comprises calculating the arithmetic average of said signal strength over a user defined period of said data packet preamble.

4. The method of claim 3 wherein said user defined period is selected such that the calculated

average signal strength is time-independent.

5. The method of claim 4 wherein said step of determining occurs after processing by a low latency filter associated with said diversity receiver.

6. The method of claim 5 wherein said step of determining occurs before processing by a high latency filter, and wherein said high latency filter is used to process the remainder of said received data packet.

7. The method of claim 6 further comprising the step of selecting one of said at least two antennae based on a signal strength measurement of a midamble associated with said received data packet.

8. The method of claim 1 wherein a digital direct current component and a gain component remain static during the step of determining.

9. A diversity receiver in a wireless network for selecting between one of at least two antennae on a per packet basis, said diversity receiver comprising:

(a) at least two antennae; and

(b) a diversity select circuit communicating with said at least two antennae,

wherein said diversity select circuit selects between one of said at least two antennae based on a metric associated with a preamble of a packet received over a wireless communication link.

10. The diversity receiver of claim 9 wherein said metric is a signal strength associated with said received packet preamble.

11. The diversity receiver of claim 10 wherein said diversity select circuit further comprises:

(a) a power averaging component for calculating the average signal strength over a defined period of time of a preamble of said received packet;

(b) an RSSI detect component for converting said average into a dB value; and

(c) a diversity select component for determining if said average signal strength exceeds a user defined signal strength threshold and selecting between one of said at least two antennae based on the results of said determination.

12. The diversity receiver of claim 11 wherein said diversity select circuit further comprises a low latency filter and wherein said preamble is examined after processing by said low latency filter.

13. The diversity receiver of claim 12 wherein said preamble is examiner before processing by

a high latency filter, and wherein said high latency filter used to process the remainder of said received data packet.

14. The diversity receiver of claim 13 wherein said diversity select circuit selects between one

of said at least two antennae based on a metric associated with a midamble of said received packet.

15. The diversity receiver if claim 13 wherein said diversity select circuit further comprises a digital direct current compensation component and a gain component, and wherein said components remain static during the operation of said diversity select component.

16. A diversity receiver in a wireless network for selecting between one of at least two antennae on a per packet basis, said diversity receiver comprising:

(a) means for receiving a wireless transmission; and

(b) means for selecting between one of said at least two antennae based on a metric associated

with a preamble of a packet received over said wireless transmission.

17. In a wireless communication system, a method of selecting an antenna from at least two antennae on a per packet basis, the method comprising:

(a) step for receiving, at each of said at least two antennae communicating with a diversity receiver, a data packet transmitted over a wireless communication link, said data packet comprising at least a preamble and said preamble having a signal strength associated therewith;

(b) step for determining said data packet preamble signal strength associated with a first antenna; and

(c) step for selecting said first antenna if the determined signal strength exceeds a predetermined threshold.