초록 ▼

A communications waveform format is provided for a satellite-based telecommunications system. The waveform format includes forward and return link waveforms between the satellite, earth stations and terminals. The forward and return links use orthogonal direct-sequence code division multiple access

A communications waveform format is provided for a satellite-based telecommunications system. The waveform format includes forward and return link waveforms between the satellite, earth stations and terminals. The forward and return links use orthogonal direct-sequence code division multiple access (ODS-CDMA) to minimize interference between users. The forward and return link spectrum may be divided into channels, the frequencies and spacing of which are adjustable to compensate for Doppler effects, thereby maintaining synchronization. The spectrum of the terminal links may be divided into multiple subbands (e.g., 38), each of which may support multiple (e.g., 80) ODS-CDMA channels. The forward and return links support traffic channels (TCH), associated signaling channels (ASC), broadcast control channels (BCC), forward signaling channels (FSC) having paging slots (PAS) and channel allocation slots (CAS), call establishment channels (CEC), and loop signaling channels (LSC), a measurement reporting channel (MRC), and a return access channel (RAC). The RAC carries nonsynchronous spread spectrum pseudo-noise (PN) signal access bursts which are used by terminals to initially access the communications system.

대표청구항 ▼

1. A data signal, modulated by an orthogonal CDMA code, embodied in a carrier wave forming a satellite based telecommunications link between earth stations and terminals via satellites, said data signal comprising: a plurality of frames comprised of a sequence of quadrature phase shift keying (QPSK)

1. A data signal, modulated by an orthogonal CDMA code, embodied in a carrier wave forming a satellite based telecommunications link between earth stations and terminals via satellites, said data signal comprising: a plurality of frames comprised of a sequence of quadrature phase shift keying (QPSK) code symbols, said QPSK code symbols within each of said frames being partitioned into a sync field and a multiuse field, each of said frames beginning with said sync field followed by said multiuse field; said sync field containing predetermined QPSK code symbols enabling acquisition and tracking of frequency and chip timing by a terminal and identifying a frame boundary; and said multiuse field comprising a loop signaling field, a measurement reporting field, and a traffic field.