Telefonaktiebolaget Lm Ericsson (Publ)

Ericsson Gmbh

Torbjorn Ward

Anders Sandell

Daniel Dufour

Kenneth Wallstedt

Norio Iizuka

A system and method for minimizing effects of both internal and external transmitter noise in order to improve control decisions that are based on signal strength measurements. A wireless network includes an internal transmitter transmitting a first signal at a first frequency and noise at other frequencies in a known pattern. The signal strength of the first signal is measured by the receiver at the first frequency. The noise of the transmitter of the first signal is calculated on other frequencies, using the first transmitter's known noise pattern. A determination is then made whether the noise of the first signal is above a threshold on one or more of the other frequencies used by the wireless communication system. If the noise is above the threshold, corrective action is taken. The wireless network further includes one or more receivers that measure signal strengths on the range of frequencies used by the system. A correlation is made between the known spectral pattern of transmitters external to the system and the signal strength measurements. If the correlation is above a threshold, then external noise is present and corrective action is taken.

Detecting and minimizing the effects of transmitter noise on signal strength measurement in a wireless communication system

Each base station in a cellular telephone system includes a signal strength measurement device operable to tune to and make signal strength measurements on not only the voice channels assigned to other cells, but also on its own voice channels. The measurements on the own voice channels provide an indication of injected interference useful in making quality driven voice channel assignments during either call set-up or hand-off. In a conventional analog cellular system, the signal strength measurement device comprises the base station signal strength receiver measuring on own idle base station analog voice frequencies. In a time division multiple access (TDMA) cellular system, the signal strength measurement device comprises the base station location verification module measuring during idle time slots on digital voice frequencies.

Quality driven voice channel selection in a cellular telephone system

A neighborhood zone covering an enclosed or surrounded environment, such as a man-made building or high-rise, is defined within a mobile telecommunications network by associating a plurality of base stations with respective cell areas. A same neighborhood list indicating all measurement channels being utilized within the neighborhood zone by said plurality of base stations is then further defined. The defined same neighborhood list is then transmitted by each of the base stations within its respective coverage area. A mobile station traveling within the neighborhood zone then scans and reports measurements from the indicated measurement channels to the serving mobile telecommunications network. The mobile telecommunications network then effectuates a handover in accordance with the received signal measurements. An idle mobile station further utilizes the measurements to effectuate a cell re-selection.

Providing a neighborhood zone within a mobile telecommunications network

A system and method for dynamically adapting the user bit rate of a time division multiple access (TDMA) cellular telecommunication system to achieve optimum voice quality over a broad range of radio channel conditions are disclosed. The system continuously monitors radio channel quality on both the uplink and the downlink, and dynamically adapts the system's combination of speech coding, channel coding, modulation, and number of assignable time slots per call to optimize voice quality for the measured conditions. Various combinations of the system's speech coding, channel coding, modulation, and assignable time slots are identified as combination types and corresponding cost functions are defined. By identifying and selecting the cost function with the lowest cost for the measured radio channel conditions, the system provides the maximum voice quality achievable within the limits of the system design.

System and method for flexible coding, modulation, and time slot

The time division multiple access (TDMA) frame time synchronization error for received mobile station burst communications transmitted on the reverse digital control channel is monitored by the receiving base station. A probability density function is then prepared by the base station reflecting the number of instances of each determined length of time synchronization error monitored over a predetermined time period. The probability density function is then processed to identify the percentage of burst communications during that predetermined time period that exceed a synchronization error threshold. If the determined percentage exceeds a given percentage, then abbreviated length burst communication operating mode is ordered by the base station for all mobile stations operating within the cell. Otherwise, conventional length burst communication operating mode is ordered by the base station. The measured time synchronization error is continuously processed to effectuate dynamic control over the specified length of mobile station burst communications.

Method and apparatus for dynamically selecting the length of mobile

A digital radiocommunication system and method for providing a consistency check to confirm the identity of a candidate cell for handoff of a digital traffic channel are described. Using relative pathloss comparisons reliance on absolute measurements which can lead to inappropriate handoffs for a variety of reasons. Statistical measurements can also be used to further reduce errors.

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Montreal, Canada

Torbjorn Ward