Charles E. Wheatley

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. >

CDMA reverse link open loop power control

An open-loop power control algorithm for code-division multiaccess (CDMA) cellular mobile telephony is presented. The algorithm is optimum in the sense of minimizing the mobile transmitted power and hence reduces the level of interference. Normally, the open-loop power control is used to mitigate long-term variations. The mobile unit measures the total received power and uses the measurement to estimate the transmission loss. This estimate is used to permit a rapid response to changes in the channel characteristics. It is shown that the open-loop mobile transmitted power is inversely proportional to its total received power. The constant can be part of a broadcast message that it is sent by the home cell. It is shown that the constant is sensitive to system parameters such as the cell effective radiated power (EPR), noise figure, antenna gain, the set of E/sub b//N/sub t/, and system loading. The open loop should have a large dynamic range (80 dB) and a reasonable fast response in order to accommodate subscriber units passing behind buildings or subject to shadowing effects. Data collected from both the laboratory and field tests support the analytical results presented.<<ETX>>

Geolocation technologies and applications for third generation wireless

Wireless Service Providers have become increasingly interested in developing position location services for commercial application of the evolving Third Generation (3G) communication systems. The initial and driving force behind this interest is a regulation in the United States promulgated by the Federal Communications Commission, requiring wireless carriers to be capable of delivering the position of a wireless device (or mobile station) making an emergency call to emergency authorities by October 2001. Similarly in Europe, the 1999 Communications Review (COM 1999/539) set the date of 1 January 2003 for the carriers to make location information available for emergency authorities. The cellular mobile station geolocation problem can be solved using either network-based methods or handset-based methods. A hybrid position location method that combines measurements from the communication systems forward and/or reverse links with measurements from the Global Positioning System (GPS) can improve position service availability. Given the ability to accurately determine a users location means that position location service applications can and most certainly will provide value-added features such as navigation, fleet management, real-time traffic updates, location sensitive billing, etc. In this paper we present different geolocation technologies, list some of the important applications, and review the status of the location services in the 3G Standards Development Organizations. Copyright