Patent Application
20060099912
1. Field
The present disclosure is directed to a method and apparatus for transmit power level reporting with reduced interference. More particularly, the present disclosure is directed to removing adjacent channel interference when reporting transmit power level measurements.
2. Description of Related Art
Presently, radio frequency channels are being overused and cell sizes are being reduced in wireless communication systems. Accepted reuse patterns and adjacent channel buffers are changing. Unfortunately, with higher density channel reuse, radio frequency channel power measurements being artificially boosted by interference from adjacent cells affects handover algorithms and timing. For example, artificially high traffic channel (TCH) power measurement reporting can lead to delayed handovers and dropped calls. When the interference is at an initial stage, it boosts reported radio frequency power levels. As the interference increases it causes decode errors on the channel and leads to poor call performance.
TCH hopping can help reduce interference. This can provide for overall better signaling performance, but still does not completely address the potential of measurement interference. For example, a boost in the reported level on a TCH of as little as 2 dB can delay a handover long enough to result in a dropped call. There is no accommodation for bad measurements. For example, it has been seen in certain power measurement logs that interference from adjacent channels can influence the measured radio frequency power level by as much as 40 dB.
Thus, there is a need for a method and apparatus for transmit power level reporting with reduced interference.
A method and apparatus for transmit power level reporting with reduced interference. An average radio frequency power level can be computed from measurements for each of a plurality of radio frequency channels of a hop sequence. The presence of interference can be detected on a radio frequency channel. The total average radio frequency power level of the plurality of radio frequency channels can be calculated without the radio frequency power level of the radio frequency channel having the presence of interference. The total average radio frequency power level can be reported to a base station.
The embodiments of the present disclosure will be described with reference to the following figures, wherein like numerals designate like elements, and wherein:
In operation, the base stations can broadcast cell and system information on a broadcast channel (BCH). The base stations can utilize a traffic channel (TCH) to transfer speech, circuit switched data, or other information between the wireless communication device 110 and the base stations. To avoid interference between sectors and cells, a base station can engage in channel hopping by changing channels or frequencies based on a selected sequence. While it is possible for the system 100 to predict the movement of the wireless communication device 110 between adjacent sectors, such as 121 and 123 or 121 and 143 it is difficult to determine when the wireless communication device 110 has moved between non-adjacent sectors, such as 121 and 131. Yet, the wireless communication device 110 can detect and correct such movement, as discussed below.
The display 340 can be a liquid crystal display (LCD), a light emitting diode (LED) display, a plasma display, or any other means for displaying information. The transceiver 350 may include a transmitter and/or a receiver. The audio input and output circuitry 330 can include a microphone, a speaker, a transducer, or any other audio input and output circuitry. The user interface 360 can include a keypad, buttons, a touch pad, a joystick, an additional display, or any other device useful for providing an interface between a user and a electronic device. The memory 370 may include a random access memory, a read only memory, an optical memory, a subscriber identity module memory, or any other memory that can be coupled to a mobile communication device.
In operation, the transceiver 350 can send and receive wireless communication signals. The controller 320 can compute an average radio frequency power level from measurements for each of a plurality of radio frequency channels of a hop sequence. The interference detection module 390 can detect the presence of interference on a radio frequency channel. The controller 320 can then calculate a total average radio frequency power level of the plurality of radio frequency channels without the radio frequency power level of the radio frequency channel having the presence of interference. The transceiver 350 can then report the total average radio frequency power level to a base station.
The controller 320 can disregard measurements corresponding to the radio frequency channel having the presence of interference when calculating the total average radio frequency power level. The controller 320 can compute an average radio frequency power level on a plurality of radio frequency channels of a hop sequence by computing an average radio frequency power level on each radio frequency channel of the hop sequence. The interference detection module 390 can detect the presence of interference by detecting a signal level of at least one radio frequency channel of the hop sequence not being accordance with other channels in the hop sequence. The interference detection module 390 can also detect the presence of interference by detecting an abnormal signal to noise ratio on a specific radio frequency channel in the hop sequence. The abnormal signal to noise ratio can be a lower signal to noise ratio on a specific channel than on other channels in the hop sequence. The interference detection module 390 can additionally detect the presence of interference by detecting the presence of a radio frequency channel that is adjacent to a radio frequency channel in the hop sequence. An adjacent channel can be a radio frequency channel that is within 200 kHz of a radio frequency channel in the hop sequence.
The method of this disclosure is preferably implemented on a programmed processor. However, the controllers, flowcharts, and modules may also be implemented on a general purpose or special purpose computer, a programmed microprocessor or microcontroller and peripheral integrated circuit elements, an ASIC or other integrated circuit, a hardware electronic or logic circuit such as a discrete element circuit, a programmable logic device such as a PLD, PLA, FPGA or PAL, or the like. In general, any device on which resides a finite state machine capable of implementing the flowcharts shown in the Figures may be used to implement the processor functions of this disclosure.
While this disclosure has been described with specific embodiments thereof, it is evident that many alternatives, modifications, and variations will be apparent to those skilled in the art. For example, various components of the embodiments may be interchanged, added, or substituted in the other embodiments. Also, all of the elements of each figure are not necessary for operation of the disclosed embodiments. For example, one of ordinary skill in the art of the disclosed embodiments would be enabled to make and use the teachings of the disclosure by simply employing the elements of the independent claims. Accordingly, the preferred embodiments of the disclosure as set forth herein are intended to be illustrative, not limiting. Various changes may be made without departing from the spirit and scope of the disclosure.
