Spread-spectrum, frequency-hopping radio telephone system with voice activation

• US 5,619,493 A
• Filed: 02/26/1996
• Issued: 04/08/1997
• Est. Priority Date: 11/03/1992
• Status: Expired due to Fees

• Current Assignee: Rafael - Armament Development Authority Ltd.
• Original Assignee: Rafael - Armament Development Authority Ltd.
• Inventors: Livneh, Noam, Silbershatz, Giora, Ritz, Mordechai
• Primary Examiner(s): Olms, Douglas W.
• Assistant Examiner(s): PHILLIPS, MATTHEW
• Application Number:
  US08/606,587
• Time in Patent Office: 407 Days
• Field of Search: 370/124, 370/118
• US Class Current: 370/330
• CPC Class Codes: H04B 1/713 using frequency hopping
• CPC Class Codes: H04B 1/7143 Arrangements for generation of hop patterns
• CPC Class Codes: H04B 1/715 Interference-related aspects
• CPC Class Codes: H04B 2001/7154 with means for preventing interference
• CPC Class Codes: H04B 7/2634 for channel frequency control
• CPC Class Codes: H04W 16/02 Resource partitioning among network components, e.g. reuse partitioning
• CPC Class Codes: H04W 16/12 Fixed resource partitioning
• CPC Class Codes: H04W 16/24 Cell structures
• CPC Class Codes: H04W 16/28 using beam steering

Abstract

A multiple access communications system reuses a set of N carrier frequencies in adjacent communications sites to provide more than N minimally cross-correlated frequency-hopping communications channels. A first set of communications channels is associated with a first of the communications sites. No two of the channels in the first set employ the same frequency at the same time. A second set of communications channels is associated with a second of the adjacent communications sites. No two of the channels in the second set of channels employ the same one of the N carrier frequencies at the same time. One or more sets of the minimally cross-correlated channels are further defined so that none of the channels in such sets employ the same frequency at the same time as more than a predetermined number of the channels in another of the sets of the minimally cross-correlated frequency-hopping communications channels. The signal activity level of a frequency-hopped transmission is detected on one of the frequencies of the hopping pattern. The transmission is deactivated when the signal is silent. When signal activity resumes, the signal is transmitted with a new hopping sequence.

Claims

1. A method of providing multiple access communications in a communication system having a plurality of fixed frequency channels in which signals are transmitted, comprising the steps of:

transmitting a signal spread over the plurality of fixed frequency channels in accordance with a sequence of frequency channels;

detecting the signed activity level of the transmission of the signal on one of the plurality of fixed frequency channels to generate a voice activity signal;

deactivating the transmission of the signal when the voice activity signal indicates that the signal is silent; and

transmitting the signal in accordance with a new sequence of frequency channels when signal activity resumes.

2. A multiple access communication system, comprising:

means for transmitting a signal spread over a plurality of fixed frequency channels in accordance with a sequence of frequency channels;

means for detecting the signal activity level of the transmission of the signal on one of the plurality of fixed frequency channels to generate a voice activity signal;

means for deactivating the transmission of the signal when the voice activity signal indicates that the signal is silent; and

means for transmitting the signal in accordance with a new sequence of frequency channels when signal activity resumes.