Showing papers by "Amitava Ghosh published in 1999"

Data transmission within a spread-spectrum communication system

Abstract: Remote units (113) having large amounts of data to transmit will be dynamically assigned Orthogonal Variable Spreading Factor (OVSF) codes corresponding to higher data rates and remote units (113) with lower amounts of data to be transmitted will be assigned OVSF codes corresponding to lower data rates. The reduction of the data rate between the base station (100) and remote units (113) occurs by changing the current OVSF codes utilized by both the remote units (113) and the base station (100). In order to eliminate collisions among remote units transmitting data, a remote units transmission is advanced and retarded in time based on an amount of offset from a frame boundary.

Method and apparatus for communicating signals of various channel types in cdma communication systems

Abstract: In a code division multiple access communication system providing a plurality of communication type services between a first unit (100) and a second communicating unit (200) by time-multiplexing a plurality of data channel signals (101, 102, 103) associated with the plurality of communication type services to produce a time-multiplexed data channel signal (106) which are combined to produce a combined signal (136). Combined signal (136) is transmitted from first unit (100) to be received by second unit (200). After producing a code-demultiplexed time-multiplexed data channel signal (218), and a plurality of signal-to-interference ratios estimated based on a plurality of time-multiplexed portions of signal (218), a plurality of power control thresholds corresponding to the plurality of communication type services are compared to the plurality of signal-to-interference ratios. As a result, producing a plurality of power control data bits corresponding to the plurality of communication type services based.

Shared channels for packet data transmission in W-CDMA

Abstract: One of the targets for a wideband CDMA (W-CDMA) system is to provide an efficient transfer of low bit rate to very high bit rate packet data services. A shared channel concept has been proposed for both the downlink and uplink channels that is better suited for bursty packet data traffic. The shared channels allows UEs to transmit and receive data bursts at high rates by using short leases on the radio resource thereby lowering the overall delay by taking the greatest advantage of statistical multiplexing. The high rate bursts require the network tightly manage its resources to insure that the appropriate OVSF codes are assigned on the downlink and the aggregate interference does not exceed the noise rise on the uplink. In both cases, the network must convey the new assignments on a frame by frame basis. In this paper, packet data transmission using both downlink shared channel (DSCH) and uplink shared channel (USCH) is discussed for a W-CDMA system.

Method and device for position finding in radio communication multiple-user code-access system

Abstract: FIELD: CDMA communication system. SUBSTANCE: according to first claim of invention method involves sending location request to user by means of extended spectrum signal, and receiving user's response which specifies time of reception of character of base sequence of spectrum extension, and time for transmission of character of user sequence of spectrum extension. One base as well other receiving bases, receives preliminary defined character of user sequence of spectrum extension, so that each base detects corresponding time for reception of this preliminary defined signal. This received information is processed together with known information about position of base and delay time information in order to detect position of user. If number of bases to achieve connection to a particular user is small, for example, due to heavy load or noise, method involves additional bases for achieving duplex communication with given user. EFFECT: increased functional capabilities, increased efficiency. 10 cl, 9 dwg