摘要:
A procedure for triggering a handdown or a handoff a mobile station served by a base station of a cellular wireless communication system. A tolerable path loss for signal links between the base station and a mobile station located within the base station's cell, is initially determined. A control signal is radiated at a known transmit power level from the base station over its cell. A receive power level threshold is determined for the control signal for reception by the mobile station, according to the transmit power level and the tolerable path loss. A handoff of the mobile station is triggered after deriving the received power level of the control signal at the mobile station, and determining that the received power level is less than the receive power level threshold. In one embodiment, a mobile station reports to a serving base station only after the former determines that the received power level of a control signal from the base station is less than a threshold level initially provided to the mobile station by the base station. The procedure is applicable, e.g., to base station cells of a first CDMA cellular system which cells border on cells of an analog (AMPS) or a second CDMA cellular system.
摘要:
Disclosed is a method for improving call quality and capacity by integrating a dynamic channel allocation technique into an intelligent antenna system. The intelligent antenna systems includes beams which are grouped into sets, wherein each set has associated a long list and a primary short list, and each beam has associated a secondary short list. In one embodiment, long term interference levels are measured on each beam in a set of beams for a plurality of communication channels to produce the long list; short term interference levels are measured on each beam in the set of beams for a portion of the plurality of communication channels to produce a plurality of secondary short lists and the primary short list; and communication channels are assigned to a mobile-station from the portion of the plurality of communication channels based on the measured short term interference levels on each beam in the set of beams. The long list and the primary short list are based upon highest measured long and short term interference levels, respectively, for each of the plurality of communication channels across each beam in the set of beams.
摘要:
Link performance is measured in a code division multiple access (CDMA) personal communication service (PCS) or cellular system, or other type of wireless system, using a test set-up which permits the simulation of various changes in system configuration. An illustrative embodiment includes a first attenuator arranged in a common portion of a receive path and a transmit path of a mobile station of the system, and a second attenuator arranged in either a receive-only portion of the receive path or a transmit-only portion of the transmit path. The amounts of attenuation provided by the first and second attenuators are decoupled such that a different amount of attenuation can be provided on the transmit path than on the receive path. Performance of forward and reverse links of the system are measured while varying a value of at least one of the first or second attenuators. For a given measurement, the attenuator values may be selected to simulate performance of the system in a configuration in which base station amplifier power is increased or decreased. As another example, the attenuator values may be selected to simulate performance of the system in a configuration in which cell size is increased. This arrangement of decoupled forward and reverse link attenuation in accordance with the invention permits efficient and accurate determination of link balance conditions.
摘要:
The present invention provides a method and an apparatus for a wireless communication between a base station and at least one mobile station. The method includes receiving a request for a data rate from the mobile station on a reverse link channel to the base station. The method further includes, in response to the request, skipping a first slot after a delay for a portion of a slot on a forward link transmission before transmitting a data packet in a second slot. By beginning the forward link transmission at the start of the second slot, for example, a software module may cause the base station to skip a slot immediately after the half slot delay. This additional delay of one slot or a portion of the slot may expand radius of a cell for a wireless communication between the base station and the mobile station in a relatively high-speed wireless data network.
摘要:
A code-division multiple access power control for paging channel power and initial traffic channel power dynamically determines optimum initial channel power in accordance with pilot signal strength of a pilot signal as received at a mobile station and current forward link loading of the desired sector. The optimum initial paging channel power and initial traffic channel power may be determined either at a base station or a mobile switching center of the mobile communication system. A paging signal or call is transmitted from the base station to the mobile station over a paging channel and a traffic channel at the optimum paging channel and initial traffic channel power.
摘要:
The present invention, in illustrative embodiments, implements systems and methods for adjusting the timing of access requests in mobile communications systems, such as IS-95-A mobile telephone systems, to reduce the likelihood of request collisions—especially during periods of very high calling rates. These embodiments employ measurements of access channel occupancy, as well as system operator inputs, to develop thresholds and parameter translations at a base station. Execution of control algorithms at a base station advantageously yields modified persistence test parameters sent to mobile stations. When overload conditions are present, these modified parameters cause the mobile stations to experience variable delays through judicious control of persistence testing at the mobile stations.
摘要:
A method for determining the reverse link data Rate Limit for mobile stations active on the reverse link of a High Data Rate system is disclosed. In the ideal case, the Rate Limit is based on only the number of mobile stations located in a common sector that are actually active on the reverse link. Currently, the Rate Limit is determined from the total number of mobile stations in a common sector where the total includes mobiles that are transmitting and receiving. Thus, the current method includes mobile stations that are active on the forward link and may not be active on the reverse link. In this invention, a more optimum method of estimating the reverse link loading is obtained from calculations which includes only the mobile stations which are active on the reverse link. An estimate of the reverse link loading of the mobile stations in a common cell is obtained by adding together the data rates of the data sent from each mobile in a common sector during a common frame. This aggregate rate of data during the frame is filtered to minimize irregularities by using the moving average of an infinite impulse response filter and then normalized. The normalized result is a percentage of the maximum achievable aggregate reverse link rate. The final result is compared with a set of threshold values to obtain the maximum Rate Limit that is then set for each mobile station.
摘要:
In the method according to the present invention, a signal from a mobile station is received. The standard deviation of the symbol error rate is determined, and power control with adaptive adjustment of an amount of change in the target signal-to-noise ratio is performed based on the determined standard deviation of the signal error rate and a target associated therewith.
摘要:
Call processing overload at a base station of a cellular wireless network is controlled by monitoring a level of call processing at the base station, and reducing a present handoff rate for active users when the call processing level exceeds a first threshold less than a maximum call processing capacity. When the call processing level at the base station exceeds a second threshold greater than the first threshold, a present rate of call originations or terminations is reduced while further reducing the handoff rate.
摘要:
The interference on the available communication frequencies is measured during an idle time slot over a first period of time at a first rate. The available frequencies are prioritized based on the interference measurements, and a list is formed of the frequencies having the lowest interference measurements. Interference measurements are made at a second rate, greater than the first rate, for a second period of time less than the first period. When a call is assigned, the interference level requirements for the call are given, and the carrier power level of the call is measured. The carrier-to-interference ratio of each frequency in the list is determined using the second interference measurements and the measured carrier power. The frequencies in the list meeting the interference level requirements for the call are then selected, and frequency hopping while serving the call is performed using the selected frequencies.