Patent EA-000519-B1 (EA)
Title: Linear coverage area antenna system for a cdma communication system
Inventor: DEAN RICHARD F
IPC: H04B7/04
Filed: 1996-06-07
Abstract: 1. An antenna system for a base station in a digital communication system in which at least one remote terminal communicates with other terminals through a base station using digitally modulated communication signals, said base station comprising: - a first linear coverage area antenna structure; - a second linear coverage area antenna structure; and - antenna interface means for coupling said communication signals between said base station and said first and second linear coverage area antenna structures, said antenna interface means including means for splitting ones of said communication signals into first and second time-offset signal components for transmission by said first and second linear coverage area antenna structures, respectively. 2. The antenna system of Claim 1 wherein said antenna interface means includes first and second duplexers, said first and second duplexers being interposed between an analog transmitter within said base station and said first and second linear coverage area antenna structures, respectively. 3. The antenna system of Claim 2 wherein said antenna interface means includes a splitter and delay network and wherein said communication signals are generated by spread spectrum modulating information signals according to predetermined pseudorandom noise (PN) spreading codes each comprised of a predetermined sequence of binary chips each of a predetermined chip duration, said splitter and delay network providing a delay between said first and second time-offset signal components on an order of at least one chip duration. 4. The system of Claim 1 wherein said first and second linear coverage area antenna structures respectively comprise first and second leaky coaxial antennas. 5. In a digital communication system in which system users communicate through a base station with remote system users, said remote system users communicating through said base station via a radio link therewith, said base station comprising: - a first linear coverage area antenna structure; - a second linear coverage area antenna structure; - transmitter means for generating remote user directed spread spectrum signals by spread spectrum modulating system user information signals; and - antenna interface means for providing said remote user directed spread spectrum signals to said first and second linear coverage area antenna structures, said antenna interface means including means for introducing a predetermined time delay between components of said remote user directed spread spectrum signals transmitted by said first and second linear coverage area antenna structures, respectively. 6. The base station of Claim 5 further comprising first means for demodulating a first aggregate spread spectrum signal coupled from said first antenna structure, said first aggregate spread spectrum signal being comprised of a plurality of system user directed spread spectrum signals received by said first linear coverage area antenna structure. 7. The base station of Claim 6 further comprising second means for demodulating a second aggregate spread spectrum signal coupled from said second antenna structure, said second aggregate spread spectrum signal being comprised of a plurality of system user directed spread spectrum signals received by said second linear coverage area antenna structure. 8. The base station of Claim 5 wherein said system user information signals are spread spectrum modulated according to predetermined pseudorandom noise (PN) spreading codes each comprised of a predetermined sequence of binary chips each of a predetermined chip duration, said predetermined time delay being on an order of at least one chip duration. 9. The base station of Claim 5 wherein said first and second linear coverage area antenna structures respectively comprise first and second leaky coaxial antennas. 10. The base station of Claim 5 wherein said first and second linear coverage area antenna structures are disposed to radiate electromagnetic energy substantially continuously along a longitudinal dimension thereof. 11. A system for transmitting a forward link spread spectrum modulated information signal and receiving a reverse link spread spectrum modulated information signal wherein said forward and reverse spread spectrum modulated information signals are generated by spread spectrum modulating information signals with pseudorandom noise codes each predetermined pseudorandom noise code comprised of a predetermined sequence of code chips each of a predetermined chip duration, said system comprising: - a first antenna structure having a linear coverage area; - a second antenna structure having a linear coverage area; and - antenna interface means for providing said forward link spread spectrum modulated information signal to said first and second linear coverage area antenna structures, said antenna interface means including means for introducing a delay equivalent to at least one of said predetermined chip durations between components of said forward link spread spectrum modulated information signal transmitted by said first and second antenna structures, respectively; - wherein said linear coverage area of said first antenna structure and said linear coverage area of said second antenna structure substantially overlap. 12. The system of Claim 11 further comprising a plurality of demodulation elements wherein a first one of said plurality of demodulation elements receives a first component of said reverse link spread spectrum signal from said first antenna structure and a second one of said plurality of demodulation elements receives a component of said reverse link spread spectrum signal from said second antenna structure. 13. The system of Claim 12 wherein said first and second ones of said demodulation elements each demodulate a signal from a common remote user further comprising a diversity combiner for combining an output of said first one of said demodulation elements and an output of said second one of said demodulation elements. 14. The system of Claim 13 further comprising a searcher engine for identifying multiple receptions said signal from said common remote unit. 15. The system of Claim 12 an interface switch for coupling a third one of said plurality of demodulation elements either to said component of said reverse link spread spectrum signal from said first antenna structure or to said component of said reverse link spread spectrums signal from said second antenna structure. 16. The system of Claim 11 wherein said first antenna structure is a leaky coaxial cable. 17. The system of Claim 11 wherein said first antenna structure is triaxial coax cable. 18. The system of Claim 11 further comprising a remote unit located within said substantial overlap wherein said remote unit comprises a plurality of demodulation elements for demodulating a chosen forward link signal within said component of said forward link spread spectrum modulated information signal transmitted by said first antenna structure and for demodulating said chosen forward link signal within said component of said forward link spread spectrum modulated information signal transmitted by said second antenna structure/ respectively. 19. A method for effecting distributed transmission of said digitally modulated communication signals in a digital communication system in which at least one remote terminal is in communication with a base station using digitally modulated communication signals, comprising the steps of: - splitting ones of said digitally modulated communication signals from said base station into first and second signal components of different time delay and coupling said first and second signal components of said digitally modulated communication signals to said first and second linear coverage area antenna structures. 20. The method of Claim 19 wherein said communication signals are generated by spread spectrum modulating information signals according to predetermined pseudorandom noise (PN) spreading codes each comprised of a predetermined sequence of binary chips each of a predetermined chip duration, further including the step of providing a delay between said first and second signal components of different time delay on an order of at least one chip duration. 21. A method for effecting distributed transmission and reception of spread spectrum communication signals in a digital communication system in which system users communicate through a base station with remote system users via a radio link therewith, comprising the steps of: - generating remote user directed ones of said spread spectrum signals by spread spectrum modulating user information signals; and - providing said remote user directed ones of said spread spectrum signals to said first and second linear coverage area antenna structures, and introducing a predetermined time delay between components of said remote user directed ones of said spread spectrum signals transmitted by said first and second linear coverage area antenna structures, respectively. 22. The method of Claim 21 further including the step of demodulating a first aggregate spread spectrum signal coupled from said first antenna structure, said first aggregate spread spectrum signal being comprised of a plurality of system user directed ones of said spread spectrum signals received by said first linear coverage area antenna structure. 23. The method of Claim 22 further including the step of demodulating a second aggregate spread spectrum signal coupled from said second antenna structure, said second aggregate spread spectrum signal being comprised of a plurality of system user directed ones of said spread spectrum signals received by said second linear coverage area antenna structure. 24. The antenna system of Claim 21 wherein said first and second linear coverage area antenna structures are separated by greater than a wavelength of said spread spectrum communication signals while maintain substantially overlapping cove