Telefonaktiebolaget Lm Ericsson (publ)

Ericsson Gmbh

Dayong Chen

Dennis Hui

Abdulrauf Hafeez

Evin Feli

Leonard Lee

John Walter Diachina

Stephen G Craig

Stefan G Eriksson

A demodulator is provided that functions as a reduced-state equalizer and produces reliable soft bit values. According to an embodiment, soft bit values are generated for a sequence of transmitted symbols using a demodulator by updating an M-state trellis managed by the demodulator responsive to a transition from symbol time n&#x2212;1 to symbol time n, where M is a function of the number of bits per symbol in the sequence of transmitted symbols. Survivor metrics associated with the M states of the trellis are saved each symbol time so that the demodulator can calculate soft bit values with regard to transitions from symbol time n+D&#x2212;1 to symbol time n+D. The trellis is traced back through to calculate soft bit values for a symbol detected at symbol time n&#x2212;D based on survivor metrics saved for the M states at symbol time n&#x2212;D.

Method and apparatus for generating soft bit values in reduced-state equalizers

A demodulator is provided that functions as a reduced-state equalizer and produces reliable soft bit values. According to an embodiment, soft bit values are generated for a sequence of transmitted symbols using a demodulator by updating an M-state trellis managed by the demodulator responsive to a transition from symbol time n&#x2212;1 to symbol time n, where M is a function of the number of bits per symbol in the sequence of transmitted symbols. Survivor metrics associated with the M states of the trellis are saved each symbol time so that the demodulator can calculate soft bit values with regard to transitions from symbol time n+D&#x2212;1 to symbol time n+D. The survivor metrics indicate the probability that each respective state represents the transmitted symbol associated with symbol time n+D&#x2212;1. The trellis is traced back through to calculate soft bit values for a symbol detected at symbol time n&#x2212;D based on survivor metrics saved for the M states at symbol time n&#x2212;D.

A method and apparatus in a base station for jointly controlling sub-channel transmission power and assigned codec modes for a first and second mobile station utilizing Voice services over Adaptive Multi-user channel on One Slot (VAMOS). The base station receives signal quality information reports from the mobile stations every 480 ms using the Slow Associated Control Channel (SACCH), and receives codec mode requests from the mobile stations every 40 ms using Adaptive Multi-Rate (AMR) in-band signaling. The base station associates the requested codec modes with estimated levels of speech quality currently being experienced by the first and second mobile stations. The base station then allocates sub-channel transmission power and assigns codec modes to the first and second mobile stations based on the estimated levels of speech quality associated with the requested codec modes and the signal quality reports.

Integrated power control and link adaptation

According to a method and apparatus taught herein, a network node includes a receiver circuit that determines soft values for received packets corresponding to the information bit groups associated with network coding operations, where the soft values are determined for each information bit group based on joint probabilities of the information bits within the information bit group. For example, first soft values are determined for the information bit groups in a first (received) constituent packet and second soft values are likewise determined for the information bit groups in a network-coded (received) packet that depends on the first constituent packet and a second constituent packet. Third soft values are generated for the information bit groups of the second constituent packet based on jointly evaluating the first and second soft values.

Method and apparatus for the use of network coding in a wireless communication network

A hybrid channel estimator for a wireless communication system receiver includes both correlation based and least squares based channel estimators. The correlation estimator is used when signal quality is low or noise is colored. The least squares estimator is used when signal quality is high or noise is white. An interference suppression filter improves signal quality by suppressing interference in a received signal. Generally, correlation channel estimation is performed initially, when signal quality is low and noise is colored, and interference suppression filtering is performed to increase signal quality by removing certain portion of interference and whitening the overall impairment spectrum. These may be done iteratively. When the signal quality improves, least squares channel estimation is performed, which may also be iterative. The training sequence and noise may be whitened prior to performing least squares channel estimation, which is the final operation before channel estimates are forwarded to a demodulator.

Hybrid correlation and least squares channel estimation

A method and apparatus blindly detects a received signal's modulation type characterizing an impairment component of the received signal for each postulated modulation type by determining spatial correlations between In-phase and Quadrature components of the received signal. The blind detection circuit then detects the modulation type based on the characterized impairment component. A metric generator generates a postulation metric for each postulated modulation type based on the characterized impairment component. After evaluating the postulation metrics, an evaluation circuit identifies the postulated modulation type having the best postulation metric as the modulation type of the received signal. According to an exemplary embodiment, the blind detection circuit determines a whitened noise estimate for each postulated modulation type and generates the postulation metrics based on the whitened noise estimate to reduce interference effects in the postulation metrics.

Method and apparatus for interference cancellation in communication signal processing

In a wireless communication network using point-to-point or point-to-multipoint communications, this disclosure teaches the use of combined packets for retransmission and corresponding soft value processing at a receiver, wherein combined packets are formed as the logical combination of two or more previously transmitted packets and allow the receiver to use a single combined packet to correct one or more failed packets. For example, with the combined packet retransmission and corresponding soft value receiver processing as taught herein, a given receiver can use a given combined packet to correct bit errors in all (failed) packets comprising the combined packet as long as the bit errors in a failed packet do not overlap (or align) with bit errors in the other failed packets comprising the combined packet.

Method and apparatus for combined packet retransmission and soft decoding of combined packets in a wireless communication network

A received information signal is decoded to obtain the received information and to produce at least one feature of the received information signal. The received information signal is preliminarily classified as containing a normal burst or a truncated burst based upon the at least one feature, to obtain a preliminary classification. Cyclic redundancy checking of the received information that is decoded is performed. The received information signal is then further classified as containing a normal burst or a truncated burst based upon the preliminary classification and whether the cyclic redundancy checking is valid, to obtain a further classification. The received information signal may be still further classified as containing a normal burst or a truncated burst based upon the further classification and at least one transition rule for normal bursts and truncated bursts between the received information signal and a previously received information signal.

Systems and methods for detecting discontinuous transmission (DTX) using cyclic redundancy check results to modify preliminary DTX classification

A method of mapping input bit positions in an input sequence to output bit positions in an output sequence uses compressed mapping sequences stored in memory derived from a predetermined mapping function. The mapping function is decompressed into periodic component functions that are used to generate the compressed mapping sequences. Each compressed mapping sequence comprises a plurality of partial mapping values that represent one period of a corresponding component function or group of component functions. Partial mapping values are selected from each compressed mapping sequence based on a bit index of the current input bit and summed or otherwise combined to get an output index.

Interleaving/de-interleaving using compressed bit-mapping sequences

The invention involves selection of modulation scheme for a mobile unit () having access to a link quality enhancing algorithm () operable only on data modulated using a subset of the available modulation schemes. The mobile unit () performs signal quality measurements on a communications link (), over which data modulated with a first modulation scheme is communicated. A link quality measure is then determined for this first modulation. A quality enhancement due to operation of the algorithm () is also determined. This quality measure and the quality enhancement are used for generating decision information, which is reported to the network (). There the information is used for estimating link quality measure(s) of currently non-employed modulation(s) for the mobile unit (). The selection of a modulation scheme for the communications link is then performed based on the decision information and the estimated quality measure(s).

Modulation scheme management

A wireless communications system receiver classifies a received burst as a DTX-high state normal burst or a DTX-low state truncated burst with a high probability of success. D1, the Euclidean distance between the known CDVCC and the bit position of CDVCC in a normal burst, is determined by calculating a confidence-weighted correlation between the two bit patterns. In a high-noise environment, D2, the Euclidean distance between the known CDVCC and the bit position of CDVCC in a truncated burst, is calculated. The ratio D1/D2 is compared to a threshold to classify the DTX state of the received burst. D1 and D2 may be normalized by dividing by the maximum average RSSI over the received burst, plotted on a graph of normalized D1 vs. normalized D2, and compared to a predetermined thresholding function that minimizes the probability of false classification. The thresholding function may be a piece-wise linear curve.

DTX detection method with high success probability

Differential puncture patterns are used for puncturing and de-puncturing codewords transmitted over a communication channel. The puncture pattern comprises a series of successive differential indices or offsets corresponding to differences between successive bit indices in an absolute bit index sequence. The differential puncture patterns are used at the transmitter to select bits of a codeword for transmission over the communication channel. At the receiver, the differential puncture pattern is used to determine the bit positions of received bits in a de-punctured codeword.

Puncturing/depuncturing using compressed differential puncturing pattern

A received information signal is decoded to obtain the received information and to produce at least one feature of the received information signal. The received information signal is preliminary classified as containing a normal burst or a truncated burst based upon the at least one feature, to obtain a preliminary classification. Cyclic redundancy checking of the received information that is decoded is performed. The received information signal is then further classified as containing a normal burst or a truncated burst based upon the preliminary classification and whether the cyclic redundancy checking is valid, to obtain a further classification. The received information signal may be still further classified as containing a normal burst or a truncated burst based upon the further classification and at least one transition rule for normal bursts and truncated bursts between the received information signal and a previously received information signal.

A network receiver is dynamically configurable to process access bursts received from mobile stations as both normal-type and abbreviated-type access bursts. With this capability, radio signal measurement data may be collected in the network cell or sector in which the receiver is positioned for signals originating from mobile stations operating in surrounding cells, whether or not those surrounding cells use the same burst structure. In an exemplary implementation, the receiver determines whether access burst data exhibits a lower error rate when processed as a normal burst, or when processed as an abbreviated burst. The data derived from the processing approach that yields the lower error rate is then compared with an error threshold defining an unacceptable error level for the burst data. If the data is below the threshold, it is retained for post-processing analysis, where it is used to develop accurate inter-cell measurement data for the network.

Efficient radio reception method for automatic frequency planning

Asymmetric frequency allocation for packet channels in a wireless network. Asymmetric radio spectrum allocation along with multiple duplex carrier types within a spectrum allocated in uplink and downlink blocks of frequencies provides greater capacity for downlink traffic. Each uplink block of frequencies has multiple associated downlink blocks of frequencies. When the invention is employed for packet channel operations in a TDMA-based network, the base station system can assign timeslots to the mobile station on an asymmetric carrier. The base station system also assigns a flag value to the mobile station for use in packet channel operations. In the case of GSM, the flag is an uplink state flag.

Growing community of inventors

Cary, NC, United States of America

Dayong Chen