In the torn paper channel, a transmitted codeword is broken at random locations into fragments that arrive at the decoder in an unordered manner. A central theoretical challenge within this model is global alignment -- the task of determining each fragment's original position -- in order to faithfully reconstruct the entire codeword. Prior work by Shomorony and Vahid introduced an interleaved-pilot scheme that successfully achieved a vanishing error probability. However, their alignment strategy relies heavily on global statistics, requiring fragments to exceed a minimum length and effectively discarding many shorter ones as erasures, which results in rates significantly below capacity. To address this gap, we propose an improved coding scheme that achieves a provable rate increase through a novel approach we call \textit{local alignment}. This approach identifies global alignment bits within each fragment using only local information, allowing the decoder to determine the positions of fragments that are shorter than those used in previous work. Consequently, the decoder can extract information from a much larger fraction of the channel output than in previous work, yielding significantly higher rates. Furthermore, we extend our analysis to torn paper coding with lost pieces (TPC-LP), a generalized model that accounts for length-dependent fragment deletion. For a class of TPC-LP channels that delete all fragments below a logarithmic length threshold while allowing arbitrary length-dependent deletion probabilities for longer fragments, we show that the proposed local alignment strategy achieves an arbitrarily small additive gap to capacity as the threshold increases.

Focusing on the problem of target recognition in complex land backgrounds, a target identification method using scanning correlation and beam pointing is proposed in this paper. Considering the complex scattering characteristics of ground clutters, correlation thresholds associated with range and angles are set to eliminate false targets. Firstly, seeker scanning is implemented twice from left to right, then from right to left to eliminate the negative influences of ground clutters. The information of the detected targets during scanning including range and angles are stored. Point or body identification is realized based on the high-resolution range profile (HRRP). Finally, error distribution area is calculated by combining with the beam pointing information from the fire control system. Target identification is realized by finding the nearest target.

For ultra-wideband (UWB) communications with signal energy dispersed by a large number of multipath compnents, the design of a Rake receiver that can provide a desirable output signal-to-noise ratio (SNR) using only a moderate number of fingers becomes an important issue. In this paper, we propose a pilot-channel-assisted log-likelihood-ratio selective combining (PCA-LLR-SC) scheme for UWB Rake receivers to be used in long-range low-rate UWB communications envisioned by the IEEE 802.15.4a PHY specification. The pilot and data channels are constructed using quadrature sinusoidal bursts that have the same Gaussian envelope. The system parameters are optimized through jointly minimizing the channel estimation mean square error and maximizing the receiver output SNR. Extensive simulations confirm that the proposed PCA-LLR-SC scheme is capable of providing robust low-rate UWB communications in fast-fading multipath channels and in the presence of multi-user interference.

Providing diversity is one of the two possible objectives (the other one is providing multiplexing) of a multi-input multi-output (MIMO) system. For ultra wideband (UWB) impulse radio systems using rake receivers, there are already richly inherent multipath diversities. However, there may be UWB applications making use of more than one UWB transmit antenna and/or receive antenna, which leads to UWB MIMO systems. The difference between the diversity analyse of a UWB MIMO system from that of a narrow band system lies in the different choice of propagation channel model for the branches linking each transmit antenna and receive antenna. Similar to the narrow band system, the existence of the correlation between the branches can severely degrade the diversity performance, and complicate the performance analyse. In this paper, the wideband propagation channel for the UWB MIMO system, with pre-defined correlation model for the branches, is broken down into several uncorrelated elementary narrow-band propagation channels with equivalent diversity performance. Based on this, a novel method for evaluating the diversity performance of a MIMO UWB impulse radio system is presented.

In this paper, we propose a pulse-coded orthogonal M-ary pulse position modulation (PPM) scheme that employs coded equivalent pulses, for non-coherent receivers operating in low-data-rate ultra-wideband (UWB) communications. Major system parameters, such as the size of pulse coding and the temporal spacing between adjacent pre-coding pulses, are provided to fully exploit the FCC average- and peak-power constraints. Simulation results show that the performance of the proposed scheme in conjunction with a square-law detector applying fixed large integration duration compares favourably with that of a selective Rake receiver, under realistic UWB channel models