Abstract: In a wireless communication system which includes a synchronization signal generator which generates a synchronization sequence, an RF transmitter which transmits the synchronization signal, and one or more receiver that receives the signal, where the synchronization sequence employs M PN codes of the same length that are repeated in a pseudo-random fashion for N code periods. Each receiver incorporates M filters matched to the M PN codes whose outputs are post detection combined in a manner consistent with the pseudo-random code transmission sequence to provide signal detection and synchronization. In another aspect, the synchronization sequence employs M time-shifted versions of a PN code that are repeated in a pseudo-random fashion for N code periods and each receiver incorporates a filter matched to the unshifted PN code and whose output samples are post detection combined in a manner consistent with the pseudo-random code transmission sequence to provide signal detection and synchronization.

Abstract: Data packets are selected for simultaneous transmission to multiple users using a transmitter with limited transmission power by first establishing transmission power requirements for each user, receiving in a queue a plurality of data packets for transmission to one or more users, and selecting one or more data packets for transmission in a composite burst with cumulative power for the selective packets not exceeding the limited transmission power. Data packets are selected for sequential composite bursts until all data packets in the queue have been transmitted, at which time transmission ceases until more incoming packets arrive at the queue. In selecting data packets for transmission, data packets which have previously been delayed in transmission can be given priority as well as priority based on quality of service subscribed by each user. Additionally a predetermined priority weight can be assigned to data packets and used for selection.

Abstract: 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-CDM channels.

Abstract: An ODS-CDMA communications system is disclosed with at least one hub station and a plurality of user terminals. Each user is assigned a code which is orthogonal to all of the other user codes. The orthogonal code period is chosen such that the code repeats an integer number of times in a data symbol time and the code is synchronized with the symbol transitions so that no data transitions occur within the code. Thus, the selection of an orthogonal code book which enables a high rate data to be spread using shorter code words, and conversely, low data rate to be spread using longer code words, all of which remain mutually orthogonal.

Abstract: Data packets are selected for simultaneous transmission to multiple users using a transmitter with limited transmission power by first establishing transmission power requirements for each user, receiving in a queue a plurality of data packets for transmission to one or more users, and selecting one or more data packets for transmission in a composite burst with cumulative power for the selective packets not exceeding the limited transmission power. Data packets are selected for sequential composite bursts until all data packets in the queue have been transmitted, at which time transmission ceases until more incoming packets arrive at the queue. In selecting data packets for transmission, data packets which have previously been delayed in transmission can be given priority as well as priority based on quality of service subscribed by each user. Additionally a predetermined priority weight can be assigned to data packets and used for selection.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: A method of paging assigns a unique digital address to mobile stations with each unique digital address being mapped into an orthogonal signal set which is then transmitted to all mobile stations. Each mobile station then correlates a received orthogonal signal function against an orthogonal function corresponding to its address. More particularly, each orthogonal signal set comprises a binary orthogonal signal set such as a set of Rademacher-Walsh functions. Other well known orthogonal function sets can be employed. For example, an mbit address can be partitioned into g binary sequences and each sequence is then uniquely mapped into one of 2.sup.m/g orthogonal functions.

Abstract: A method and an apparatus are provided for transmission of band limited QPSK data which is orthogonal direct-sequence spread using a BPSK sequence which preserves the band limiting even with subsequent amplification by non-linear amplifiers. This feature allows inexpensive implementation in mass produced, portable communications devices.

Abstract: An adaptive filter or equalizer for digital data communication includes, a first cascade circuit connected to operate as a digital finite impulse response (FIR) filter, the first cascade circuit having a first plurality of input taps for application of filter weighting signals thereto, a single input for samples of input data, and an output for filtered data. A second cascade circuit, which has the inverse canonical form, has a second plurality of input taps for receiving signal samples of input data, a single input for receiving error signals, and an output for yielding a succession of weighting signals. A sequencing circuit applies data signals to successive cascade stages of the second cascade circuit in a time sequence which is the reverse of that of the weight signals applied to the plurality of input taps of the first cascade circuit, such that the second cascade circuit functions as a weighting signal generator for the first cascade circuit.

Abstract: A conical scan tracking system for spacecraft and radio sources employing a large antenna detects small sinusoidal modulation in received power from a source that is off target with a frequency equal to a very low scan rate, an amplitude proportional to angular deviation of the source from the target, and a phase directly related to the direction the source is off target. The sinusoid is digitally correlated with inphase and out-of-phase (90.degree.) scan sinusoids to obtain azimuth/elevation and hour angle/declination signals which are digitally integrated over exactly one scan period (e.g., 10 to 100 sec) to obtain correction signals for an antenna pointing subsystem.