Abstract: A range equalization transceiver system (100) for increasing efficiency of a continuous duty communications link includes a first transceiver (105) for transmitting data traffic over a broadband traffic channel and a second transceiver (107) for determining routing information using a discovery channel based on link quality. A controller (103) is used for interpreting routing information from the second transceiver (107) where the controller (103) selects a transmitting scheme based on data traffic conditions on both the broadband traffic channel and link quality channel for sending data over a wireless network.

Abstract: A receiver configured for: a) receiving (410) a first OFDM symbol and generating a plurality of demodulated symbols for the first OFDM symbol; b) generating (420) decoder output code symbols corresponding to a subset of the plurality of demodulated symbols; c) determining (430) that a set of the decoder output code symbols make up a set of reference symbols corresponding to at least a portion of the subset of the plurality of demodulated symbols; d) generating (440) the set of reference symbols; e) generating (450) a set of channel estimates based on the set of reference symbols and the at least a portion of the subset of the plurality of demodulated symbols, for use in decoding a current OFDM symbol; and f) repeating steps b-e until a channel estimate for each demodulated symbol corresponding to the first OFDM symbol has been generated.

Abstract: This invention extends Alamouti's scheme for wideband TDMA systems; it then works in conjunction with time-domain equalization. In fact, the present invention envisages time-domain DFE or MLSE equalization (which is more robust than linear frequency-domain equalization) via the use of a training mid-amble to separate adjacent sub-blocks; this mid-amble is used in equalizer training and its direct and inter-symbol interference contributions to the received signal, are subtractively eliminated to facilitate the detection process itself. This approach may be applied to all systems in time-dispersive propagation media, where the burst or slot length is short enough that the fading can be considered time-invariant over its duration.

Abstract: A system that includes a receiver (100) that is configured for: selecting (210) a set of demodulator output samples and a corresponding set of reference symbols; generating (220) a set of raw channel estimates based on the set of demodulator output samples and the corresponding set of reference symbols; subdividing (230) the set of raw channel estimates into a plurality of subsets; assigning and applying (240) a corresponding reference symbol magnitude quantization scheme to each subset; determining (250) a set of filter coefficients that is based on the quantization schemes applied to the subsets of raw channel estimates; and combining (260) the set of raw channel estimates with the set of filter coefficients to generate a channel estimate.

Abstract: A system that includes a receiver (100) that is configured for: selecting (210) a set of demodulator output samples and a corresponding set of reference symbols each having a magnitude; generating (220) a set of raw channel estimates based on the set of demodulator output samples and the corresponding set of reference symbols; determining (230) a set of linearly-constrained filter coefficient parameters; and combining (240) the set of raw channel estimates with the set of linearly-constrained filter coefficient parameters to generate a channel estimate.

Abstract: A wireless communication unit provides (10) a first signal as received from a first portion (11) of a single antenna and provides (13) a second signal as received from a second portion of the antenna, which in a preferred embodiment can comprise a feedline (12). The two signals contain information that is cross-coupled with respect to one another as a function, at least in part, of the structure of the antenna. A digital processing platform (34) de-couples (17) these signals to permit recovery of the original payloads. In one embodiment similar approaches are used to facilitate cross-coupling of signals and transmission of such cross-coupled signals from different portions of a single antenna structure. In another embodiment, both transmission and reception are facilitated by a common platform.

Abstract: A method for determining a frequency error over at least one frequency search space for a received signal, the method including the steps of: calculating a first noise estimation for a first frequency offset in a frequency search space; calculating at least a second noise estimation for a second frequency offset in the frequency search space; and determining a minimum noise estimation from the calculated noise estimations, wherein the frequency error is the frequency offset corresponding to the minimum noise estimation.

Abstract: A wireless communication unit provides (10) a first signal as received from a first portion (11) of a single antenna and provides (13) a second signal as received from a second portion of the antenna, which in a preferred embodiment can comprise a feedline (12). The two signals contain information that is cross-coupled with respect to one another as a function, at least in part, of the structure of the antenna. A digital processing platform (34) de-couples (17) these signals to permit recovery of the original payloads. In one embodiment similar approaches are used to facilitate cross-coupling of signals and transmission of such cross-coupled signals from different portions of a single antenna structure. In another embodiment, both transmission and reception are facilitated by a common platform.

Abstract: This invention extends Alamouti's scheme for wideband TDMA systems; it then works in conjunction with time-domain equalization. In fact, the present invention envisages time-domain DFE or MLSE equalization (which is more robust than linear frequency-domain equalization) via the use of a training mid-amble to separate adjacent sub-blocks; this mid-amble is used in equalizer training and its direct and inter-symbol interference contributions to the received signal, are subtractively eliminated to facilitate the detection process itself. This approach may be applied to all systems in time-dispersive propagation media, where the burst or slot length is short enough that the fading can be considered time-invariant over its duration.

Abstract: A method for controlling an adaptive antenna array (50) is provided and includes receiving a plurality of signals, each signal including a series of signal data symbols (42) and signal non-data symbols (38, 40) divided into symbol transmission units with the signal non-data symbols (38, 40) disposed among the signal data symbols (42) in each unit and each signal related to the other signals of the plurality of signals as reflections of an original signal. The method also includes separating the signal non-data symbols (38, 40) from the signal data symbols (42), and comparing the signal non-data symbols (38, 40) to a set of known non-data symbols. The method further includes determining a set of weights according to the comparison of the signal non-data symbols (38, 40) to the set of known non-data symbols, the weights to be combined with the signal data values (42) to limit the effect of interference on the signal data symbols (42).

Abstract: A base site (104) generates a pseudo-random signal based on at least one system parameter known to both the base site and a communication unit (112). The base site (104) then transmits the pseudo-random signal to the communication unit via an idle communication resource (102). Upon receiving the pseudo-random signal, the communication unit (112) determines at least one characteristic of the idle communication resource (102) using the pseudo-random signal.

Abstract: An antenna array portion of a communication device receives a desired signal and an interfering signal. The unweighted desired and interfering signals from a first antenna (302) are then combined in a summer (308) with weighted versions of the signals from a second antenna (304) to produce a received RF signal (312). The signal-to-noise ratio (SNR) of the received RF signal (312) is then estimated using a spectral analysis technique. This estimate, along with the complex weights applied to the signal from the second antenna, is then stored. Utilizing feedback and a methodology for searching through a range of sets of complex weights, the weights optimizing the SNR are determined and used to weight subsequent signals from the second antenna.

Abstract: A wireless communication system (100) that includes a plurality of base sites (101-103) employs a method and apparatus for determining a location of a communication unit (107) in the system. Upon transmission of an information signal (109) by the communication unit, each of the base sites receives the transmitted information signal. A serving base site (e.g., 103) determines a stream of information symbols from the information signal, derives timing information based on the information signal and the stream of information symbols, and conveys the stream of information symbols preferably to at least two non-serving base sites (101-102). The non-serving base sites determine respective timing information based on the information signal received from the communication unit and the stream of information symbols received from the serving base site.

Abstract: EMI spur interference is reduced in a system where the desired signal has periodically repeating components without destructively interfering with the repeating components. The frequency of the spur interference is determined (203) and fed to a notch filter (201) so as to center the notch at the frequency of the spur interference. Determination of the frequency is scheduled (601) to avoid cancellation of desired periodically repeating components of the signal.

Abstract: A method determines the signal usability of an adjacent channel in a multi-cell communication system without the aid of synchronization symbols. In general, a three step search is used to arrive at the adjacent channel signal quality. The first step is a coarse timing phase search. This is accomplished through a signal quality estimates (606). The second step arrives at the optimum time phase by first interpolating (608) the received signal around the time phase selected in the first step to generate additional samples. After the interpolation (608), signal quality estimates are calculated (610) for the time phases immediately surrounding the time phase found in the first step. The optimum time phase corresponds to the maximum of these quality estimates. Finally, in the third step, the signal quality estimate is calculated for the optimum time phase. This provides the adjacent channel signal quality estimate desired.

Abstract: A method of low-splatter peak-to-average reduction for a linear communication system includes the step of sampling (1201) an input signal at a first rate, yielding a plurality of input samples. When at least one (1401, 1403, and 1405) of the plurality of input samples is above a first threshold, a local maximum (1401) is determined (1207) from among the plurality of input samples. At least one value (1407 and 1409) is interpolated (1207) between the local maximum and at least one sample (1405) adjacent to the local maximum. The at least one value and the local maximum are compared (1211) to determine which has the highest magnitude. The value having the highest magnitude (1407) is compared (1213) to a second threshold. When the value having the highest magnitude (1407) is above the second threshold, an attenuating window is centered (1505) at the value having the highest magnitude and applying (1507) the attenuating window to at least some of the plurality of input samples.

Abstract: In a diversity reception communication system (200), a method is provided for recovering data symbols (213) from a transmitted signal. Multiple signals representing the transmitted signal are received via corresponding multiple reception paths (201, 202). For each reception path, values are determined for noise (206), channel quality (207), and for a weighting factor (209) as a function of the channel quality. The signals are processed using diversity combining (212) which includes the weighting factor (209) for each reception path, to provide a resultant signal that more likely represents the transmitted signal than any of the received signals alone. The data symbols (213) are recovered from the resultant signal.

Abstract: In a Radio Frequency (RF) communication system using Time Division Multiple Access (TDMA) having time slots of a common duration, a quantity of information bits to be transmitted is provided. Based at least in part on the number of information bits to be transmitted, a modulation technique is selected from a plurality of modulation techniques. Based at least in part on the modulation technique selected and the common duration of the time slots, the information bits are formatted into blocks, each block containing an equal number of information bits. The blocks are transmitted in the time slots such that a predetermined symbol rate is maintained.

Abstract: A quad 16 QAM transmission and reception methodology wherein a time domain pilot reference is advantageously associated therewith. There may be one or more such pilot references for each packet of multiple 16 QAM pulses. Depending upon the embodiment, each 16 QAM pulse can include a time domain pilot reference, or an estimated pilot reference for that pulse can be determined either by reference to pilot references in other pulses sharing the same packet, or by reference to pilot references for other previously received 16 QAM pulses corresponding to that same pulse.

Abstract: A diversity receiver that receives modulated signals may determine signal usability of the received signals in the following manner. A modulated signal that includes a desired component and an undesired component is received in each receiver branch of the diversity receiver, wherein the desired component includes an originally transmitted signal and the undesired component includes noise and interference. Each receiver branch estimates the desired and undesired components and processes the modulated signal with a channel gain/phase estimator, a complex conjugator, and a complex mixer to produce a complex output. The complex output of each receiver branch is derived independently of the undesired component and combined to produce a diversity resultant. The diversity receiver estimates the signal usability of the diversity resultant based on the estimated desired components and the estimated undesired components.