Irwin M. Jacobs

On the capacity of a cellular CDMA system

It is shown that, particularly for terrestrial cellular telephony, the interference-suppression feature of CDMA (code division multiple access) can result in a many-fold increase in capacity over analog and even over competing digital techniques. A single-cell system, such as a hubbed satellite network, is addressed, and the basic expression for capacity is developed. The corresponding expressions for a multiple-cell system are derived. and the distribution on the number of users supportable per cell is determined. It is concluded that properly augmented and power-controlled multiple-cell CDMA promises a quantum increase in current cellular capacity. >

Increased capacity using CDMA for mobile satellite communication

The performance of a spread-spectrum CDMA (code-division multiple access) system in a mobile satellite environment is analyzed. Comparisons to single-channel-per-carrier FDMA systems are presented which show that the CDMA approach provides greater capacity. Results from computer simulations, laboratory tests, and field tests of a prototype modem are also presented. The tests results show excellent performance of the modem in the mobile environment and also the feasibility of the spread-spectrum approach to satellite mobile communications. >

General purpose packet satellite networks

The use of satellite communication techniques to provide integrated data network and point-to-point and conference speech services is discussed. The concept of a General Purpose Packet Satellite Network (GPSN) is introduced in terms of its requirements, and consideration is given to techniques that satisfy these requirements. The class of Priority Oriented Demand Assignment (PODA) algorithms is defined and compared with other packet-oriented demand assignment algorithms. PODA is shown to be well suited to the GPSN application. Networking and access protocol issues are considered in the context of a GPSN. The Atlantic Packet Satellite Experiment, an ongoing experimental program which is developing packet satellite technology, is described in some detail.

The OmniTRACS/sup R/ Mobile Satellite Communications and Positioning System

The OmniTRACS two-way mobile satellite communications and position reporting system is described. This system provides message communications between moving vehicles and their operations centers. Me mobile unit directly communicates with a central hub facility which provides system control, message processing and archival, and point-to-point communications with the operations centers. QASPR, a dual satellite positioning system giving accuracies in the United States to about 1/4 mile, is described. Experiences and benefits to the trucking industry are also highlighted.

The application of a novel two-way mobile satellite communications and vehicle tracking system to the transportation industry

A two-way mobile satellite communications and vehicle position reporting system currently operational in the US and Europe is described. The system characteristics and service operations are described in detail, and technical descriptions of the equipment and signal processing techniques are provided. The application of this technology to the land transportation industry, specifically the over-the-road truckload motor carrier segment, and the types of benefits being derived by the current users are described. >

Cpoda - a demand assignment protocol for satnet

A new contention-based demand assignment protocol (CPODA) is described. The protocol is designed to handle packetized data and voice traffic in a multiple access satellite broadcast channel, where the channel is typically shared by hundreds of earth stations. A sophisticated traffic environment is assumed, including multiple priority and delay class distinctions, variable message lengths, and an arbitrary load distribution among the stations. In addition, stations may have different receiving rate capabilities. The CPODA protocol is part of a broader research project concerned with developing protocols for a one-hop satellite network (SATNET). The CPODA and other protocols are currently undergoing experimental evaluation using an INTELSAT IV-A satellite and four earth stations in the Atlantic region.

OmniTRACS: a commercial Ku-band mobile satellite terminal and its applicability to military mobile terminals

The technical characteristics of the OmniTRACS system are described. This system is the first operational mobile Ku-band satellite communications system and provides two-way message and position determination service to mobile terminals using existing Ku-band satellites. Interference to and from the system is minimized by the use of spread-spectrum techniques, together with low-power, low-data-rate transmissions. The applicability of this technology to implement a military mobile terminal operating over existing SHF satellites is also presented. Features discussed include the return- and forward-link modulating signals, the return-link power density, and the mobile-terminal hardware.<<ETX>>