Classifications

• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04B—TRANSMISSION
  • H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
  • H04B1/69—Spread spectrum techniques
  • H04B1/707—Spread spectrum techniques using direct sequence modulation
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04B—TRANSMISSION
  • H04B7/00—Radio transmission systems, i.e. using radiation field
  • H04B7/14—Relay systems
  • H04B7/15—Active relay systems
  • H04B7/204—Multiple access
  • H04B7/216—Code division or spread-spectrum multiple access [CDMA, SSMA]
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02D—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN INFORMATION AND COMMUNICATION TECHNOLOGIES [ICT], I.E. INFORMATION AND COMMUNICATION TECHNOLOGIES AIMING AT THE REDUCTION OF THEIR OWN ENERGY USE
  • Y02D30/00—Reducing energy consumption in communication networks
  • Y02D30/70—Reducing energy consumption in communication networks in wireless communication networks

Definitions

• PCS Communications Systems
• CDMA Code Division Multiple Access
• each beam compared to orthogonal systems such as FDMA or TDMA, which would typically
• the Globalstar application discloses a signal which is essentially the same as the IS-95
• This system uses Orthogonal CDMA (OCDMA) on the forward
• OCDMA forward and return links are being considered for satellite PCS systems.
• the capacity of a synchronous OCDMA system can be increased, under certain
• OCDMA system may be increased by employing 1 :3 frequency reuse rather than full frequency
• frequency isolation is more important than additional
• the object of this invention is to allow the capacity increase in a synchronous OCDMA
• Another object of this invention is to allow the capacity increase in a synchronous
• OCDMA system gained by employing a frequency reuse factor other than one, and still allow
• a spread spectrum CDMA communication system in which one or more base stations
• the base station(s) transmits a signal for each beam which is
• PN pseudo-noise
• Each subscriber terminal has a receiver
• frequencies are formed to be assigned in the 1 :N ra beam frequency reuse pattern.
• a spread spectrum CDMA satellite communication system in which more than one
• satellite illuminates the same region on the earth, and one or more base stations communicate
• the base station(s) transmits a signal for each beam which is comprised of a set of orthogonally spaced subcarriers, each of which is modulated by a set of orthogonal, or
• PN pseudo-noise
• Each subscriber terminal has a receiver with means to coherently
• the improvement comprising:
• a spread spectrum CDMA satellite communication system in which another satellite
• communication system illuminates the same region on the earth, and one or more base stations
• the base stat ⁇ on(s) transmits a signal for each beam which is
• PN pseudo-noise
• Each subsc ⁇ ber terminal has a receiver
• a spread spectrum CDMA satellite communication system in which another satellite
• terminals located in different beams of the multi-beam satellite relay system communicate with
• the subsc ⁇ ber terminals transmit a signal which is comp ⁇ sed
• PN pseudo-noise
• Each base station has
• subscriber terminal transmit signal to spread the signal energy over a wider
• frequencies are formed to be assigned in the 1 :N ru beam frequency reuse pattern.
• Figure 1 is a schematic illustration of a satellite based OCDMA communication system
• Figure 2 is a graph illustrating four orthogonal subcarriers spaced at the chipping rate
• Figure 3 is a functional block diagram of OCDMA subcarrier generation
• Figure 4 is a graph illustrating subcarriers spaced by 3 *Rc across available spectrum
• Figure 5 is a graph illustrating three sets of subcarriers assigned to mutually orthogonal
• Figure 6 illustrates a typical multibeam antenna pattern with band segments assigned
• Figure 7 is an illustrating of beam signals with spreading code P 2 applied with chipping
• Figure 8a is a graph showing the normalized power spectrum of beam signals before
• Figure 8b is a graph of normalized power spectrum of beam signal after spreading with
• the invention is intended for a satellite communication system in which the satellite
• the satellite signal may be relayed from a
• base station or it may be generated on the satellite.
• the FL OCDMA signal preferably incorporates the improvements of Natali U.S.
• Each subcarrier is modulated with up to Nu orthogonal binary sequences, each carrying
• each orthogonal function carries the data for a different user, however
• orthogonal codes are overlaid
• the orthogonal signals must arrive at the receiver in time synchroni sm
• the subcarrier signal generation process is shown in block diagram form in Figure
• the present invention is further intended for a system that incorporates the improvement
• the subcarriers are spaced
• N m 3.
• N m sets of disjoint subcarrier frequencies are available in Figure 5, and can be
• the FL signal is now modulated with a second PN sequence ? z which has chipping
• the adjacent beam signals are isolated from the m-beam signal by virtue of the

Landscapes

• Engineering & Computer Science (AREA)
• Computer Networks & Wireless Communication (AREA)
• Signal Processing (AREA)
• Radio Relay Systems (AREA)
• Mobile Radio Communication Systems (AREA)

Priority Applications (4)

Applications Claiming Priority (2)

Publications (1)

Family

ID=22160721

Family Applications (1)

Country Status (7)

Cited By (1)

Families Citing this family (12)

Citations (6)

Family Cites Families (6)

• 1998
  • 1998-05-19 US US09/080,952 patent/US6075781A/en not_active Expired - Lifetime
• 1999
  • 1999-05-18 JP JP2000550291A patent/JP4527879B2/ja not_active Expired - Fee Related
  • 1999-05-18 CN CN99808840A patent/CN1310893A/zh active Pending
  • 1999-05-18 WO PCT/US1999/010905 patent/WO1999060806A1/en not_active Ceased
  • 1999-05-18 DE DE69934883T patent/DE69934883T2/de not_active Expired - Lifetime
  • 1999-05-18 AU AU49520/99A patent/AU4952099A/en not_active Abandoned
  • 1999-05-18 EP EP99933473A patent/EP1077006B1/en not_active Expired - Lifetime

Patent Citations (7)

Non-Patent Citations (1)

Also Published As

Similar Documents

Legal Events