Pulse or digital communications – Spread spectrum – Direct sequence
Reexamination Certificate
2001-04-24
2003-10-14
Tse, Young T. (Department: 2634)
Pulse or digital communications
Spread spectrum
Direct sequence
C370S329000, C370S432000, C455S450000, C455S464000
Reexamination Certificate
active
06633600
ABSTRACT:
BACKGROUND
Providing quality telecommunication services to user groups which are classified as remote, such as rural telephone systems and telephone systems in underdeveloped countries, has proved to be a challenge over recent years. The past needs created by these services have been partially satisfied by wireless radio services, such as fixed or mobile frequency division multiplex (FDM), frequency division multiple access (FDMA), time division multiplex (TDM), time division multiple access (TDMA) systems, combination frequency and time division systems (FD/TDMA), and other land mobile radio systems. Often, these remote services are faced with more potential users than can be supported simultaneously by their frequency or spectral bandwidth capacity.
Recognizing these limitations, recent advances in wireless communications have used spread spectrum modulation techniques to provide simultaneous communication by multiple users. Spread spectrum modulation refers to modulating a information signal with a spreading code signal; the spreading code signal being generated by a code generator where the period Tc of the spreading code is substantially less than the period of the information data bit or symbol signal. The code may modulate the carrier frequency upon which the information has been sent, called frequency-hopped spreading, or may directly modulate the signal by multiplying the spreading code with the information data signal, called direct-sequence spreading (DS). Spread-spectrum modulation produces a signal with bandwidth substantially greater than that required to transmit the information signal, and synchronous reception and despreading of the signal at the receiver demodulator recovers the original information. The synchronous demodulator uses a reference signal to synchronize the despreading circuits to the input spread-spectrum modulated signal in order to recover the carrier and information signals. The reference signal can be a spreading code which is not modulated by an information signal. Such use of a synchronous spread-spectrum modulation and demodulation for wireless communication is described in U.S. Pat. No. 5,228,056 entitled SYNCHRONOUS SPREAD-SPECTRUM COMMUNICATIONS SYSTEM AND METHOD by Donald L. Schilling, which is incorporated herein by reference.
Spread-spectrum modulation in wireless networks offers many advantages because multiple users may use the same frequency band with minimal interference to each user's receiver. Spread-spectrum modulation also reduces effects from other sources of interference. In addition, synchronous spread-spectrum modulation and demodulation techniques may be expanded by providing multiple message channels for a user, each spread with a different spreading code, while still transmitting only a single reference signal to the user. Such use of multiple message channels modulated by a family of spreading codes synchronized to a pilot spreading codes for wireless communication is described in U.S. Pat. No. 5,166,951 entitled HIGH CAPACITY SPREAD-SPECTRUM CHANNEL by Donald L. Schilling, which is incorporated herein by reference.
One area in which spread-spectrum techniques are used is in the field of mobile cellular communications to provide personal communication services (PCS). Such systems desirably support large numbers of users, control Doppler shift and fade, and provide high speed digital data signals with low bit error rates. These systems employ a family or orthogonal or quasi-orthogonal spreading codes, with a pilot spreading code sequence synchronized to the family of codes. Each user is assigned one of the spreading codes as a spreading function. Related problems of such a system are: supporting a large number of users with the orthogonal codes, handling reduced power available to remote units, and handling multipath fading effects. Solutions to such problems include using phased-array antennas to generate multiple steerable beams, using very long orthogonal or quasi-orthogonal code sequences which are reused by cyclic shifting of the code synchronized to a central reference, and diversity combining of multipath signals. Such problems associated with spread spectrum communications, and methods to increase capacity of a multiple access, spread-spectrum system are described in U.S. Pat. No. 4,901,307 entitled SPREAD SPECTRUM MULTIPLE ACCESS COMMUNICATION SYSTEM USING SATELLITE OR TERRESTRIAL REPEATERS by Gilhousen et al. which is incorporated herein by reference.
SUMMARY
A spread spectrum code division multiple access communication system has a plurality of traffic channels. A plurality of traffic lights have a red state and a green state. Each traffic light is associated with a traffic channel. The state of each traffic light is based on an availability of that traffic light's associated traffic channel. The base station broadcasts each traffic light over a broadcast channel.
REFERENCES:
patent: 4320513 (1982-03-01), Lampert
patent: 4901307 (1990-02-01), Gilhousen et al.
patent: 4940771 (1990-07-01), Maresca
patent: 5022049 (1991-06-01), Abrahamson et al.
patent: 5084900 (1992-01-01), Taylor
patent: 5093840 (1992-03-01), Schilling
patent: 5103459 (1992-04-01), Gilhousen et al.
patent: 5109390 (1992-04-01), Gilhousen et al.
patent: 5166929 (1992-11-01), Lo
patent: 5166951 (1992-11-01), Schilling
patent: 5166952 (1992-11-01), Omura et al.
patent: 5193094 (1993-03-01), Viterbi
patent: 5204876 (1993-04-01), Bruckert et al.
patent: 5228054 (1993-07-01), Rueth et al.
patent: 5228056 (1993-07-01), Schilling
patent: 5237586 (1993-07-01), Schilling
patent: 5241690 (1993-08-01), Larsson et al.
patent: 5245629 (1993-09-01), Hall
patent: 5253268 (1993-10-01), Omura et al.
patent: 5257283 (1993-10-01), Gilhousen et al.
patent: 5260967 (1993-11-01), Schilling
patent: 5265119 (1993-11-01), Gilhoussen et al.
patent: 5267262 (1993-11-01), Wheatley, III
patent: 5283536 (1994-02-01), Wheatley, III et al.
patent: 5295152 (1994-03-01), Gudmundson et al.
patent: 5299226 (1994-03-01), Schilling
patent: 5299228 (1994-03-01), Hall
patent: 5309474 (1994-05-01), Gilhousen et al.
patent: 5327455 (1994-07-01), De Gaudenzi et al.
patent: 5327467 (1994-07-01), De Gaudenzi et al.
patent: 5341396 (1994-08-01), Higgins
patent: 5345598 (1994-09-01), Dent
patent: 5347536 (1994-09-01), Meehan
patent: 5349606 (1994-09-01), Lovell et al.
patent: 5361276 (1994-11-01), Subramanian
patent: 5365585 (1994-11-01), Puhl et al.
patent: 5377183 (1994-12-01), Dent
patent: 5392287 (1995-02-01), Tiedemann, Jr. et al.
patent: 5396516 (1995-03-01), Padovani et al.
patent: 5396539 (1995-03-01), Slekys et al.
patent: 5404376 (1995-04-01), Dent
patent: 5406615 (1995-04-01), Miller, II et al.
patent: 5414728 (1995-05-01), Zehavi
patent: 5414729 (1995-05-01), Fenton
patent: 5416797 (1995-05-01), Gilhousen et al.
patent: 5420864 (1995-05-01), Dahlin et al.
patent: 5420896 (1995-05-01), Schilling
patent: 5430760 (1995-07-01), Dent
patent: 5440597 (1995-08-01), Chung et al.
patent: 5442662 (1995-08-01), Fukasawa et al.
patent: 5446683 (1995-08-01), Mullen et al.
patent: 5454026 (1995-09-01), Tanaka
patent: 5488629 (1996-01-01), Takahashi et al.
patent: 5519736 (1996-05-01), Ishida
patent: 5528624 (1996-06-01), Kaku et al.
patent: 5544156 (1996-08-01), Teder et al.
patent: 5548613 (1996-08-01), Kaku et al.
patent: 5550811 (1996-08-01), Kaku et al.
patent: 5559790 (1996-09-01), Yano et al.
patent: 5574775 (1996-11-01), Miller, II et al.
patent: 5654980 (1997-08-01), Latva-aho et al.
patent: 5673259 (1997-09-01), Quick, Jr.
patent: 5673286 (1997-09-01), Lomp
patent: 5712869 (1998-01-01), Lee et al.
patent: 5872810 (1999-02-01), Philips et al.
patent: 5875400 (1999-02-01), Madhavapeddy et al.
patent: 5881368 (1999-03-01), Grob et al.
patent: 5991332 (1999-11-01), Lomp et al.
patent: 6108537 (2000-08-01), Comer et al.
patent: 3743731 (1989-07-01), None
patent: 3743732 (1989-07-01), None
patent: 0462572 (1991-12-01), None
patent: 0464839 (1992-01-01), None
patent: 0526106 (1993-02-01), None
patent: 0654913 (1995-05-01), None
patent: 0656716 (1995-06-01), None
patent: 0668
Lomp Gary
Ozluturk Fatih
Silverberg Avi
InterDigital Technology Corporation
Tse Young T.
Volpe and Koenig P.C.
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