Abstract:
A Supervisory Audio Tone (SAT) based Carrier-to-Interference (C/I) ratio measurement system uses the SAT tone to determine the desired signal to undesired interferers so that an intelligent hand-off decision can be made in a digital cellular communication system. The measurement is implemented by digital signal processors which allows additional signal processing and subsequently noise rejection over analog techniques. The received level of the desired SAT as well as the received levels of the SATs for the co-channel interferers is detected. The ratio of the desired SAT level to the sum of the undesired SAT levels provides the C/I measurement. By monitoring this C/I measurement, the base station can determine when to make a hand-off. This SAT based C/I measurement system also aids in the selection of a candidate cell to which the subscriber is handed-off. Surveillance receivers in the candidate cells make SAT based C/I measurements as well as Received Signal Strength Indication (RSSI) measurements. The cell with the most favorable channel conditions would be the cell to which the hand-off is made.
Abstract:
A CDMA communication system includes a signal processor which encodes voice and nonvoice signals into data at various rates, e.g. data rates of 8 kbps, 16 kbps, 32 kbps, or 64 kbps as I and Q signals. The signal processor selects a specific data rate depending upon the type of signal, or in response to a set data rate. When the signal is received and demodulated, the baseband signal is at the chip level. Both the I and Q components of the signal are despread using the conjugate of the pn sequence used during spreading, returning the signal to the symbol level. Carrier offset correction is performed at the symbol level. A lower overall processing speed is therefore required.
Abstract:
A CDMA communication system includes a signal processor which encodes voice and nonvoice signals into data at various rates, e.g. data rates of 8 kbps, 16 kbps, 32 kbps, or 64 kbps as I and Q signals. The signal processor selects a specific data rate depending upon the type of signal, or in response to a set data rate. When the signal is received and demodulated, the baseband signal is at the chip level. Both the I and Q components of the signal are despread using the conjugate of the pn sequence used during spreading, returning the signal to the symbol level. Carrier offset correction is performed at the symbol level. A lower overall processing speed is therefore required.
Abstract:
A subscriber cluster unit for a wireless telecommunication system provides a wireless interface with a base station for a plurality of subscriber units. The cluster unit has a plurality of frequency agile modems for processing wireless communications with the base station and a plurality of subscriber line circuits, each for providing a telecommunication connection with a subscriber unit. A control processor assigns a modem for each communication between the base station and a selected subscriber unit which is coupled to one of the line circuits and associates that line circuit with the assigned modem for that communication. Thus, a subscriber unit coupled with any of the line circuits can communicate with the base station via any of the modems.
Abstract:
A wireless digital telephone system containing at least one emulated base station plus one or more subscriber stations, the emulated base station comprising a station similar to the subscriber station but having the capability of initiating a synchronization process whereby it is enabled to assign time slots to the subscriber station within the frame pattern of an amplitude signal by means of monitoring for positive edges in the signal.
Abstract:
A wireless digital telephone system containing at least one emulated base station plus one or more subscriber stations, the emulated base station comprising a station similar to the subscriber station but having the capability of initiating a synchronization process whereby it is enabled to assign time slots to the subscriber station within the frame pattern of an amplitude signal by means of monitoring for positive edges in the signal.
Abstract:
A modem interface transfers data between a high data rate interface and a wireless interface. The modem interface has a plurality of parallel data highways. Each data highway has frames with time slots for transferring data. The plurality of highways outputs data to the high data rate interface and the wireless interface in selected time slots. At least one of the data highways has an input configured to receive data from the high data rate interface in selected time slots. At least one of the data highways has an input configured to receive data from the wireless interface in selected time slots. A processor controls the transfer of data between the plurality of highways.
Abstract:
A method for simultaneously receiving and processing multiple channels of data at independent rates which share a same frequency spectrum begins with receiving a multichannel data communication signal having multiple data channels at independent data rates on the same frequency spectrum. Next, selected channels of data of the received signal are separated and the data rate for each channel is identified. Then each separated channel of the received signal is decoded at an assigned data rate using a common decoding memory. Lastly, each separated channel is directed to a different decoding means and each decoding means is assigned a data rate responsive to the identification of data rates when the channels were separated.
Abstract:
The present invention is an apparatus for reducing transmission errors by a user equipment (UE) when transmitting a communication signal. An RF communication signal is received at the UE and analyzed for errors. A correction signal is then generated based upon the analysis. Prior to transmission of the communication signal from the UE, the communication signal is corrected using the correction signal.
Abstract:
A spread spectrum base station receives a multichannel data communication signal. The multichannel data communication signal has multiple data channels at independent data rates on a same frequency spectrum. Selected channels of data of the received signal are separated and the data rate for each channel identified. Each separated channel is decoded at an assigned data rate. A common decoding memory is shared.