Transfer station for wireless telephone distribution system with time and space diversity transmission

• US 20020071435A1
• Filed: 01/29/2002
• Published: 06/13/2002
• Est. Priority Date: 09/06/1994
• Status: Active Grant

• Current Assignee: Intel Corporation
• Original Assignee: Interdigital Technology Corporation (InterDigital, Inc.)
• Inventors: LaVean, Gilbert E., Bolgiano, D. Ridgely
• Granted Patent: US 6,842,444 B2
• Time in Patent Office: Days
• US Class Current: 370/394
• CPC Class Codes: G01S 5/10 Position of receiver fixed by co-ordinating a plurality of position lines defined by path-difference measurements , e.g. omega or decca systemsG01S5/12 takes precedence ; beacons and receivers cooperating therewith G01S1/306, G01S1/308
• CPC Class Codes: G01S 5/14 Determining absolute distances from a plurality of spaced points of known location
• CPC Class Codes: H01Q 21/29 Combinations of different interacting antenna units for giving a desired directional characteristic H01Q25/00 takes precedence
• CPC Class Codes: H04B 7/022 Site diversity; Macro-diversity using two or more spaced independent antennas H04B7/04
• CPC Class Codes: H04B 7/0671 using different delays between antennas
• CPC Class Codes: H04B 7/082 selecting best antenna path
• CPC Class Codes: H04B 7/0857 using maximum ratio combining techniques, e.g. signal-to- interference ratio [SIR], received signal strenght indication [RSS]
• CPC Class Codes: H04B 7/0888 with selection
• CPC Class Codes: H04W 56/00 Synchronisation arrangements
• CPC Class Codes: H04W 64/00 Locating users or terminals or network equipment for network management purposes, e.g. mobility management

Abstract

A wireless communication system combines time and space diversity to reduce fading and simplify receiver design. In particular, a data packet which carries digital telephone traffic, is transmitted at three different times from three different antennas. The mobile subscriber receiver thus receives the same data packet at three different times from three different antennas, and uses the best data packet or combination of the data packets to reduce the effects of fading. A transfer station receives a time division multiplex multiple access (TDMA) signal from a base station carrying telephone data packet traffic to form three data packet repeats at spatially diverse antennas locations. The transfer station further modulates a code division multiple access (CDMA) system using a TDMA signal which links the mobile subscriber receiver to the transfer station. Each data packet received at the transfer station is thus retransmitted at three different times to the mobile subscriber station on a CDMA link. In one embodiment, each transfer station includes the three space diversity antennas. In a second embodiment, three transfer stations, each with one spatially diverse antenna is used. The time division and code division multiplex signals transmitted from space diversity antennas provide the ability to determine subscriber location using the same communication signals which are used for the primary telephone data communication. Specifically, the subscriber station receiver uses the absolute and relative time of arrival of the three repeated data packets to determine the respective distances of the mobile subscriber station to the three transmitting antennas. Since the transmitting antennas are at known fixed locations, receiver location is determined.

Claims

1. In a wireless communication system, wherein a data packet is communicated from a transmitter to a receiver to form a received data packet, a method for determining the location of said receiver, said system including first, second and third antennas spaced apart from each other, said method comprising:

transmitting said data packet from said first antenna to form a first transmitted data packet;

transmitting said data packet from said second antenna to form a second transmitted data packet after said first transmitted data packet;

transmitting said data packet from said third antenna to form a third transmitted data packet after said second transmitted data packet;

receiving in sequence said first, second and third transmitted data packets at said receiver forming respective first, second and third received data packets;

selecting at least one of said first and second received data packets to form said digital data at said receiver;

measuring the respective time of arrival of said first, second and third transmitted data packets at said receiver; and

computing the location of said receiver from said respective measured time of arrival of said first, second and third transmitted data packets.