An Improved Group Space-Time Block Code Through Constellation Rotation

A new improved group space-time block code (G-STBC) based on constellation rotation for four transmit antennas was proposed. In comparison with the traditional G-STBC coding scheme, the proposed space-time code has longer code length and adopts proper rotation-based symbols, which can increase the minimum distance of space-time codes and thereby improve code gain and achieve full diversity performance. The simulation results verify that the proposed group space-time code can achieve better bit error performance than both the traditional group space-time code and other quasi-orthogonal space-time codes. Compared with Ma’s full diversity full rate (FDFR) codes, the proposed space-time code also can achieve the same excellent error performance. Furthermore, the design of the new space-time code gives another new and simple method to construct space-time codes with full diversity and high rate in case that it is not easy to design the traditional FDFR space-time codes.

Performance analysis and code recognition for dual N-ary orthogonal hybrid modulation systems

A dual N-ary orthogonal hybrid modulation system is introduced in this paper, which can increase the data rate greatly compared with conventional N-ary orthogonal spread spectrum system, so it can be used for high rate data communication. Then, three code recognition algorithms are presented for dual N-ary orthogonal hybrid modulation system and the analytic bit error rate （BER） performance of the system in additive white Gaussian noise （AWGN） and fiat Rayleigh fading channel is derived. Finally, the computer simulation of the system with three code recognition algorithms is performed, which shows that the simplified maximum a posteriori （MAP） algorithm is the best for the system with a compromise between the performance and the complexity.

Computer Vision Applied to Recognition Barcodes

The bar code is one of the identification technologies used more successfully in the world. This technology was first developed as the second half of the twentieth century and quickly achieved acceptance in both industry and commerce. In this paper studies are discussed on the design, development and printing of one-dimensional barcodes of the symbologies Code 39 and Interleaved 2 of 5. There are also discussed techniques for recovering the information encoded in the bar code, which can be extended to other symbologies. The purpose of the paper is the development of an open solution with the objective to make the decoding of barcodes using computer vision techniques possible, which will be divided into four basic stages： acquisition, pre-processing, processing and presentation of results. Practical tests conducted with samples show satisfactory results, validating the operating principles of the elements involved. The proposed objective was achieved and practical tests validated the operating principles of the elements addressed by providing contribution to that segment decoding barcodes.

Research on Recognition Technology of 2-Dimensional Barcode

This paper briefly introduces the characteristics and structure of symbol QR two-dimensional code, a detailed analysis of the image processing method to identify QR code of the whole process, and the bilinear mapping method is applied to image correction, the final steps of decoding are given. The actual test results show that, the design algorithm has theoretical and practical, this recognition system can correctly read QR code, and has high recognition rate and recognition speed, has practical value and application prospect.