Antenna diversity switching system for TDMA-based telephones

• US 6,483,884 B1
• Filed: 12/30/1997
• Issued: 11/19/2002
• Est. Priority Date: 12/30/1997
• Status: Expired due to Term

• Current Assignee: Ericsson, Inc. (Telefonaktiebolaget LM Ericsson)
• Original Assignee: Ericsson, Inc. (Telefonaktiebolaget LM Ericsson)
• Inventors: Lenzo, Michael, Shen, Qun
• Primary Examiner(s): Pham, Chi
• Assistant Examiner(s): BURD, KEVIN MICHAEL
• Application Number:
  US09/000,593
• Time in Patent Office: 1,785 Days
• Field of Search: 375/347, 375/147, 375/316, 375/346, 375/349, 455/277.1, 455/134, 455/135, 342/367
• US Class Current: 375/347
• CPC Class Codes: H04B 7/0811 during preamble or gap period

Abstract

A system for selecting an antenna from a diversity of antennas in a DECT, PWT, or TDMA-based antenna selection and switching system is disclosed. When signals are received from a plurality of antennas, the wireless antenna selection and switching system automatically selects either a real-time or a time-delayed signal authentication process. The selected process then selects the antenna that will provide the clearest signal quality.

Claims

1. A method for selecting an operating antenna from a plurality (n) of antennas, comprising the steps of:

1. selecting an operating antenna as a function of received signal strength by performing the steps of;

(a) detecting the received signal strength at each of said antennas and storing a Received Signal Strength Indicator (RSSI_i) for each of said antennas, wherein RSSI₀ corresponds to a currently selected antenna;

(b) calculating a delta RSSI (Δ

RSSI_i) equal to RSSI_i minus RSSI₀ for each non-selected antenna;

(c) if a maximum Δ

RSSI_i value equals or exceeds a first predetermined quality threshold value, T₁, selecting the non-selected antenna corresponding to said maximum Δ

RSSI_i to be said currently selected antenna, resetting a cycle counter, and returning to Step 1(a);

(d) if said maximum Δ

RSSI_i value does not equal or exceed said first predetermined quality threshold value, T₁, incrementing said cycle counter, and, if said cycle counter is less than a predetermined cycle count, returning to Step 1(a), otherwise, if said cycle counter equals or exceeds said predetermined cycle count, proceeding to Step 2;

2. selecting said operating antenna as a function of a Cyclical Redundancy Check (CRC) by performing the steps of;

(a) decoding the CRC error rate of the signal received by said currently selected antenna;

(b) if the decoded CRC error rate exceeds a second predetermined quality threshold value, T₂, selecting the non-selected antenna corresponding to said maximum Δ

RSSI_i to be said currently selected antenna, resetting said cycle counter and returning to Step 1(a);

(c) if the decoded CRC error rate does not exceed said second predetermined quality threshold value, T₂, resetting said cycle counter and returning to Step 1(a).

2. The method of claim 1, wherein said step 1(b) further comprises storing said Δ

RSSI_i.

3. The method of claim 1, wherein said cycle counter is an N-bit counter.

4. The method of claim 1, wherein said plurality of antennas are coupled to a base station.

5. The method of claim 1, wherein said plurality of antennas are coupled to a portable station.

6. A method for selecting an operating antenna from a plurality (n) of antennas, comprising the steps of:

1. selecting an operating antenna as a function of received signal strength by performing the steps of;

(a) detecting the received signal strength at each of said antennas and storing a Received Signal Strength Indicator (RSSI_i) for each of said antennas, wherein RSSI₀ corresponds to a currently selected antenna;

(b) calculating a delta RSSI (Δ

RSSI₁) equal to RSSI_i minus RSSI₀ for each non-selected antenna;

(c) if a maximum Δ

RSSI_i value equals or exceeds a first predetermined quality threshold value, T₁, selecting the non-selected antenna corresponding to said maximum Δ

RSSI_i to be said currently selected antenna, resetting a cycle counter, and returning to Step 1(a);

(d) if said maximum Δ

RSSI_i value does not equal or exceed said first predetermined quality threshold value, T₁, incrementing said cycle counter, and, if said cycle counter is less than a predetermined cycle count, selecting the non-selected antenna corresponding to said maximum Δ

RSSI and returning to Step 1(a), otherwise, if said cycle counter equals or exceeds said predetermined cycle count, proceeding to Step 2;

2. selecting said operating antenna as a function of said Cyclical Redundancy Check (CRC) by performing the steps of;

(a) decoding the CRC error rate of the signal received by said currently selected antenna;

(b) if the decoded CRC error rate exceeds a second predetermined quality threshold value, T₂, selecting the non-selected antenna corresponding to said maximum Δ

RSSI_i to be said currently selected antenna, resetting said cycle counter and returning to Step 1(a);

(c) decoded CRC error rate does not exceed said second predetermined quality threshold value, T₂, resetting said cycle counter and returning to Step 1(a).

7. The method of claims 6, wherein said step 1(b) further comprises storing said Δ

RSSI_i.

8. The method of claim 6, wherein said cycle counter is an N-bit counter.

9. The method of claim 6, wherein said plurality of antennas are coupled to a base station.

10. The method of claim 6, wherein said plurality of antennas are coupled to a portable station.

11. A system for selecting an operating antenna from a plurality (n) of antennas, comprising:

1. circuitry operable to select an operating antenna as a function of received signal strength, comprising circuitry operable to;

(a) detect the received signal strength at each of said antennas and store a Received Signal Strength Indicator (RSSI_i) for each of said antennas, wherein RSSI₀ corresponds to a currently selected, antenna;

(b) calculate a delta RSSI (Δ

RSSI_i) equal to RSSI_i minus RSSI₀ for each non-selected antenna;

(c) if a maximum Δ

RSSI_i value equals or exceeds a first predetermined quality threshold value, T₁, select the non-selected antenna corresponding to said maximum Δ

RSSI_i to be said currently selected antenna, reset a cycle counter, and return to element 1(a);

(d) if said maximum Δ

RSSI₁ value does not equal or exceed said first predetermined quality threshold value, T₁, increment said cycle counter and if said cycle counter is less than a predetermined cycle count, return to element 1(a), otherwise, if said cycle counter equals or exceeds said predetermined cycle count, select said operating antenna as a function of a Cyclical Redundancy Check (CRC) using the circuitry defined in element 2;

2. circuitry operable to select said operating antenna as a function of said Cyclical Redundancy Check (CRC), comprising circuitry operable to;

(a) decode the CRC error rate of the signal received by said currently selected antenna;

(b) if the decoded CRC error rate exceeds a second predetermined quality threshold value, T₂, select the non-selected antenna corresponding to said maximum Δ

RSSI_i to be said currently selected antenna resuming operation as defined in element 1(a);

(c) if the decoded CRC error rate does not exceed said second predetermined quality threshold value, T₂, reset said cycle counter resuming operation as defined in element 1(a).

12. The system in claim 11, wherein said cycle counter is an N-bit counter.

13. The system in claim 11, wherein said system is associated with a portable station.

14. The system in claim 11, wherein said system is associated with a base station.

15. A system for selecting an operating antenna from a plurality (n) of antennas, comprising:

1circuitry operable to select an operating antenna as a function of received signal strength, comprising circuitry operable to;

(a) detect the received signal strength at each of said antennas and store a Received Signal Strength Indicator (RSSI_i) for each of said antennas, wherein RSSI₀ corresponds to a currently selected antenna;

(b) calculate a delta RSSI (Δ

RSSI_i) equal to RSSI_i minus RSSI₀ for each non-selected antenna;

(c) if a maximum Δ

RSSI_i value equals or exceeds a first predetermined quality threshold value, T₁, select the non-selected antenna corresponding to said maximum Δ

RSSI_i to be said currently selected antenna, reset a cycle counter, and resume operation as defined in element 1(a);

(d) if said maximum value does not equal or exceed said first predetermined quality threshold value, T₁, increment said cycle counter and if said cycle counter is less than a predetermined cycle count, selecting the non-selected antenna corresponding to said. maximum Δ

RSSI_i and return to element 1(a), otherwise, if said cycle counter equals or exceeds said predetermined cycle count, select said operating antenna as a function of a Cyclical Redundancy Check (CRC) using the circuitry defined in element 2;

2. circuitry operable to select said. operating antenna as a function of said Cyclical Redundancy Check (CRC), comprising circuitry operable to;

(a) decode the CRC error rate of the signal received by said currently selected antenna;

(b) if the decoded CRC error rate exceeds a second predetermined quality threshold value, T₂, select the non-selected antenna corresponding to said maximum Δ

RSSI_i to be said currently selected antenna and resume operation as defined in element 1(a);

(c) if the decoded CRC error rate does not exceed said second predetermined quality threshold value, T₂, reset said cycle counter and return to element 1(a).

16. The system in claim 15, wherein said cycle counter is an N-bit counter.

17. The system in claim 15, wherein said system is associated with a portable station.

18. The system in claim 15, wherein said system is associated with a base station.