Method for employing multipath propagation in wireless radio communications

• US 7,440,766 B1
• Filed: 06/03/2005
• Issued: 10/21/2008
• Est. Priority Date: 06/07/2004
• Status: Expired due to Fees

• Current Assignee: University of Hawai'i
• Original Assignee: University of Hawai'i
• Inventors: Forsyth, William, Shiroma, Wayne, Tuovinen, Jussi
• Primary Examiner(s): Ferguson; Keith T
• Application Number:
  US11/144,973
• Time in Patent Office: 1,236 Days
• Field of Search: 455/506, 455/504, 455/501, 455/500, 455/67.11, 455/63.1, 455/63.4, 455/65, 455/67.15, 455/67.16, 455423-425, 455/422.1, 455/403, 455/426.1, 455/426.2, 455/550.1, 455/561, 455/562.1, 343/702, 343/703, 343/878, 343/907, 342/370, 342/368
• US Class Current: 455/506
• CPC Class Codes: H01Q 3/2647 Retrodirective arrays

Abstract

A method of employing multipath propagation in wireless radio communications uses an omnidirectional transmitting/receiving antenna at one end of a transmission link to send an interrogating signal across an environment subject to multipath disturbances to a phase-conjugating retrodirective antenna, and the retrodirective antenna returns a communication signal along the multiple pathways taken by the interrogating signal to the omnidirectional antenna despite the multipath disturbances. In a simplex communication mode, the retrodirective antenna sends a return signal mixed with a communication signal to the omnidirectional antenna. In a duplex communication mode, both an omnidirectional antenna and a phase-conjugating retrodirective antenna are operated in tandem at each end of the transmission link to provide effective two-way wireless radio transmissions.

Claims

1. A method of employing multipath propagation in wireless radio communications comprising the steps of:

using an omnidirectional transmitting/receiving antenna at one end of a transmission link to send an interrogating signal across an environment subject to multipath disturbances to a phase-conjugating retrodirective antenna at the other end of the transmission link; and

operating the phase-conjugating retrodirective antenna in a cooperative transmission mode by returning a communication signal along the multiple pathways taken by the interrogating signal to be received by the omnidirectional antenna across the transmission environment despite the multipath disturbances.

2. A multipath propagation communication method according to claim 1, wherein, in a simplex communication mode, the omnidirectional antenna provides an interrogating signal which is transmitted in multipath propagation over multiple pathways through the transmission environment to the retrodirective antenna, and the retrodirective antenna sends a return signal mixed with a communication signal that is transmitted with multiple signal components directed along respective ones of the multiple pathways taken by the interrogating signal to be received by the omnidirectional antenna.

3. A multipath propagation communication method according to claim 2, wherein, in a duplex communication mode, both an omnidirectional antenna and a phase-conjugating retrodirective antenna are operated in tandem at each end of the transmission link to provide effective two-way wireless radio transmissions through the transmission environment despite any multipath disturbances.

4. A communication system for multipath propagation in wireless radio communications comprising:

an omnidirectional transmitting/receiving antenna at one end of a transmission link for sending an interrogating signal across an environment subject to multipath disturbances;

a phase-conjugating retrodirective antenna at the other end of the transmission link for receiving the interrogating signal along multiple pathways and for returning a communication signal along the multiple pathways taken by the interrogating signal to be received by the omnidirectional antenna across the transmission environment despite the multipath disturbances.

5. A communication system according to claim 4, wherein, in a simplex communication mode, the omnidirectional antenna provides an interrogating signal which is transmitted in multipath propagation over multiple pathways through the transmission environment to the retrodirective antenna, and the retrodirective antenna sends a return signal mixed with a communication signal that is transmitted with multiple signal components directed along respective ones of the multiple pathways taken by the interrogating signal to be received by the omnidirectional antenna.

6. A communication system according to claim 5, wherein, in a duplex communication mode, both an omnidirectional antenna and a phase-conjugating retrodirective antenna are provided at each end of the transmission link and operated in tandem to provide effective two-way wireless radio transmissions through the transmission environment despite any multipath disturbances.