Allen Salmasi

Bio: Allen Salmasi is an academic researcher from Qualcomm. The author has contributed to research in topics: Communications satellite & Communications system. The author has an hindex of 7, co-authored 8 publications receiving 535 citations.

On the system design aspects of code division multiple access (CDMA) applied to digital cellular and personal communications networks

Abstract: A breadboard CDMA digital cellular system was developed by QUALCOMM and demonstrated in San Diego in November 1989. In February 1990, an extensive technical field trial was carried out in midtown Manhattan with NYNEX Mobile. For the purposes of carrying out the CDMA trials and demonstrations, a total of three cell-site and two mobile prototype units were built. In each case, the demonstration system utilized two actual cell sites and one mobile and included A/B comparisons with the commercial analog system. The fundamental features of CDMA, such as power control and soft handoff, were tested and proven in a variety of field conditions. The authors describe the CDMA signal and waveform design, the CDMA system design, CDMA power control, and additional features of CDMA. >

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

Abstract: 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

Abstract: 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. >

An overview of Code Division Multiple Access (CDMA) applied to the design of personal communications networks

Abstract: CDMA is a modulation and multiple access scheme based on spread spectrum communications techniques, a well established technology that has been applied only recently to digital cellular radio communications and advanced wireless technologies such as PCN [1]– [2]. It solves the near-term capacity concerns of major markets and answers the industry’s long-term need for a next generation technology for truly portable communications in the most economic and efficient manner providing for a graceful evolution into the future generations of wireless technologies.

On the capacity of a cellular CDMA system

Abstract: 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. >

Location reporting satellite paging system with optional blocking of location reporting

Abstract: A location reporting paging communication system comprising space satellites, ground stations and a remote receiving unit adapted to resolve a global position from signals transmitted from a communication transmitter. The subscriber in possession of the remote receiving unit updates the paging network with global positioning information. A caller paging a subscriber in possession of the remote receiving unit may request the global location of the remote receiving unit. The paging network could divulge or block such information from a caller depending on the requirements of the subscriber.

Personal Security and Tracking System

Abstract: A signaling system is provided for rendering an alarm for an individual in distress combined with a locating and tracking system to thus alert and direct appropriate personnel to the needs of the individual in distress and to monitor the location of that individual. The system comprises a portable signaling unit, a remote alarm switch device, a central dispatch station, and makes use of a wireless communication system. The portable signaling unit and the remote alarm switch may be adapted to be worn at different locations on the person's body. The remote alarm switch way be concealed in the form of a wristband or in the form of any other object such as a broach, pendant, or keychain.

Zero forcing and minimum mean-square-error equalization for multiuser detection in code-division multiple-access channels

Abstract: In code-division multiple-access (CDMA) systems transmitting over time-varying multipath channels, both intersymbol interference (ISI) and multiple-access interference (MAI) arise. The conventional suboptimum receiver consisting of a bank of matched filters is often inefficient because interference is treated as noise. The optimum multiuser detector is too complex to be implemented at present. Four suboptimum detection techniques based on zero forcing (ZF) and minimum mean-square-error (MMSE) equalization with and without decision feedback (DF) are presented and compared. They combat both ISI and MAI. The computational complexity of all four equalizers is essentially the same. All four equalizers are independent of the size of the data symbol alphabet. It is shown that the performance of the MMSE equalizers is better than that of the corresponding ZF equalizers. Furthermore, the performance of the equalizers with DF is better than that of the corresponding equalizers without DF. The impairing effect of error propagation on the equalizers with DF is reduced by channel sorting.

Control, monitoring and/or security apparatus and method

Abstract: Control apparatus and method including a first control device, located at the vehicle or premises, for monitoring or detecting an event, which generates and/or transmits a first notification signal containing event information to a second control device located remote from the vehicle or premises. The second control device generates and/or transmits a second notification signal to a remote communication device for providing notification of the event occurrence. Control apparatus and method including a first control device, located at a vehicle or premises, which generates and/or transmits a first signal for activating, deactivating, enabling, or disabling, a vehicle or a premises system, equipment system, subsystem, device, component, appliance, a vehicle, or a premises, in response to a signal generated and/or transmitted from a remote second control device. The second control device is responsive to a third signal generated and/or transmitted by a remote third control device.