It is proposed that up-link relays be used to improve the data throughput for user equipment (UE) near the cell edge in a LTE network. Relay assistance on the up-link occurs when the evolved Node B (eNB) requests a retransmission (HARQ) from the UE at which point the UE and relay transmit simultaneously. The quality of the up-link signal received by the eNB is improved due to a favorable channel through the relay. An analysis and simulation show that relay assistance improves the throughput for a cell-edge user when the average delay per data transport block is allowed to increase. A modification of the up-link power control is recommended when using relays, where the maximum power transmitted by the UE is reduced.

This paper describes an echo cancellation (EC) algorithm used in a mixed mode WCDMA/GSM repeater with digital sub-band filtering. The EC coefficients are estimated iteratively from cross and power spectrums improving the computational efficiency of the estimation. The effect of regularization and spectral normalization on the convergence of an adaptive EC algorithm is investigated. Singular value decomposition (SVD) is applied to the estimation process as a form of regularization, compensating for the bandwidth reduction associated with the sub-band filter. Spectral normalization used in the estimation of the EC coefficients is shown to avoid convergence problems and the frequency- dependent cancellation that affect the baseline approach. Simulation results show echo cancellation of 23 dB across a 60 MHz bandwidth.

This paper investigates the effect of interactions between the Walsh codes and data sequences on the statistical moments of the forward-link CDMA signal. Of primary interest is the normalized fourth-order moment, which is referred to as the "power variance". Several techniques for reducing the power variance of the CDMA signal are discussed that are based on Walsh code selection and data encoding. Certain groupings of Walsh codes, referred to as "active quadruples", are shown to be useful in predicting the potential of each technique. Results demonstrate the reduction in the power variance afforded by two novel approaches referred to as "channel hopping" and "data reversal".

This paper investigates the effects of Walsh code selection and baseband filtering on the statistical moments of the band-limited forward-link CDMA signal. A normalized moment, the "power variance," is proposed as a measure of the signal's sensitivity to nonlinear amplification. The estimation of the power variance for the case of a band-limited QPSK-modulated random waveform is presented as a baseline fur illustrating the effect of filtering on a sampled signal. The band-limited CDMA signal case illustrates the interaction between the Walsh codes and the wave-shaping filter, and quantifies the influence of "missing Hadamard basis functions. "Results verify the accuracy of the statistical models and illustrate the importance of Walsh code selection in the reduction of the power variance of a band-limited CDMA waveform.

This paper develops an error bound for narrow bandwidth Gabor filters synthesized using multiple stages. It is shown that the error introduced by approximating narrow bandwidth Gabor (1946) kernels by a weighted sum of spatially offset, separable kernels is a function of the frequency offset and the reduction in bandwidth of the desired kernel compared to the basis values, as well as the spatial subsampling rate between filter stages. This error bound should prove useful in the design of a general basis filter set for multi-stage filtering because the maximum frequency offset is largely determined by the spacing of the basis filters.

This paper describes how the phase, obtained by Gabor filtering an image, can be used to aggregate related Gabor elements (simple features identified by peaks in the Gabor magnitude). This phase-based feature grouping simplifies the perennial problem of target/background segmentation because we need to only determine if the aggregate feature is target or background, rather than determine the status of each feature independently. Since the phase from a single quadrature Gabor output cannot tolerate large changes in orientation, a new local measure, referred to as the composite phase, has been developed. It is a combination of the filter responses from multiple orientations which allows the phase to follow contours with large changes in orientation. A constant composite phase contour is used to connect related Gabor elements that would otherwise appear separated within the magnitude response.

This paper presents a new representation called "hierarchical Gabor filters" and associated novel local measures which are used to detect potential objects of interest in images. The "first stage" of the approach uses a wavelet set of wide-bandwidth separable Gabor filters to extract local measures from an image. The "second stage" makes certain spatial groupings explicit by creating small-bandwidth, non-separable Gabor filters that are tuned to elongated contours or periodic patterns. The non-separable filter responses are obtained from a weighted combination of the separable basis filters, which preserves the computational efficiency of separable filters while providing the distinctiveness required to discriminate objects from clutter. This technique is demonstrated on images obtained from a forward looking infrared (FLIR) sensor.>

Recognition of aircraft in complex, perspective aerial imagery has to be accomplished in presence of clutter, occlusion, shadow, and various forms of image degradation. This paper presents a system for aircraft recognition under real-world conditions that is based on the use of a hierarchical database of object models. The particular approach involves three key processes: (a) The qualitative object recognition process performs model-based symbolic feature extraction and generic object recognition; (b) The refocused matching and evaluation process refines the extracted features for more specific classification with input from (a); and (c) The primitive feature extraction process regulates the extracted features based on their saliency and interacts with (a) and (b). Experimental results showing the qualitative recognition of aircraft in perspective, aerial images are presented.>

J.G. Daugman's (1988) neural network solution to the Gabor expansion of an image is reformulated as a steepest descent implementation. Nonlinear optimization theory is then applied to select an appropriate convergence factor. Two quasi-Newton-based nonlinear optimization techniques are applied to improve the convergence for certain types of lattice.