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Turbo Codes have been an attractive topic in coding theory community since they were introduced in 1993 due to their powerful error correcting capability and superior coding gain. Thanks to their astounding performance, Turbo codes are used in 3rd generation wireless communication and satellite communication system. Fore these applications, efficient implementation of Turbo Codes, i.e., development...
In this paper, Serial Concatenated Convolutional Code (SCCC) with Continuous Phase Modulation (focus on MSK) and Log-MAP decoding algorithm is investigated. As an alternative solution to Parallel Concatenated Convolutional Code (PCCC), which is termed Turbo Code (TC), SCCC is in some cases superior to that of TC with similar complexity, especially at high Signal-to-Noise ratio. SCCC consists of a...
In satellite mobile communications, TWT (Traveling Wave Tube) amplifiers are used to increase power efficiency. Unfortunately, power-efficient amplifiers cause nonlinear distortions to the transmitted signal These distortions make the received symbols no longer on the original regular lattice but on a warped one. Several authors use analytical models (such as Saleh model) to describe both amplitude...
In Satellite ATM (SATM) networks, the various traffic patterns and dynamically changing topology call for effective network traffic control mechanisms to reduce congestion and utilize network resource efficiently. There are two major challenges in the SATM traffic control. On one hand, the time varying traffic arises big challenges for guaranteed service in ATM. On the other hand, due to the permanent...
A micromachining technique involving the wet chemical etching of bulk silicon wafers has been used to fabricate deep three-dimensional cavity resonators at 30 GHz. Previous attempts at forming cavities using silicon micromachining have been inhibited by the shallow depth of the cavities, which were on the order of a single wafer thickness (∼0.5 mm). This seriously degrades the available unloaded Q-factor...
Digital video communication is becoming popular with the recent advances in the satellite and wireless networks, and the growing popularity of the World Wide Web. The mobile users generally have limited bandwidth, and hence it is crucial to develop efficient scalable video coding scheme for low bandwidth channels. The current video coding standards are primarily based on discrete cosine transform...
Since the introduction of turbo codes in 1993, researchers have turned their attention to the design, performance evaluation and practical application of these codes. The practical implementation of turbo decoding algorithms faces two major challenges: (1) heavy computations for the α and the β values, and (2) huge memory requirement. Using powerful fast processors, which are in hand nowadays, one...
This paper investigates multi-dimensional Block Turbo Codes (BTCs) with trellis-based decoding, which have the possibility of providing a large range of block sizes. Large block size codes can provide significant coding gain and code rates. BTCs thus provide us more attractive options for a wide range of applications and higher bandwidth efficiency. Due to their excellent power and bandwidth efficiency,...
In most MMIC and antenna applications, an accurate knowledge of the relative permittivity of materials is required. At EHF, the two-port transmission/reflection quasi-optical measurement system is an attractive solution due to its contactless and non-destructive nature and to the simplicity of sample preparation. The quasi-optical apparatus consists of a pair of collinear horn-fed lenses. The sample...
While the DVB-RCS standard turbo code, which uses quaternary alphabet and QPSK modulation, has an excellent performance, its bandwidth efficiency is limited by the puncturing and QPSK modulation to less than 2bits/s/Hz. In order to achieve bandwidth efficiencies of 2bits/s/Hz and higher, one needs coding and modulation schemes with M-ary alphabet (M>4). We have investigated an extended non-binary...
Turbo decoders are composed of two or more soft-input soft-output (SISO) decoders that exchange reliability information. A classical way of implementing a SISO decoder for a linear block code is to use a trellis-based decoding algorithm, such as MAP, Max-Log-MAP or SOVA [1]. Recently, the idea of sectionalizing the trellis diagram representing a code has been proposed as a means to decrease the decoding...
In this project, the hardware implementation of double-binary CRSC codes in the Digital Video Broadcasting (DVB) for the Return Channel via Satellite (DVB-RCS) is investigated for use in satellite communication links. The simplified Max_Log_MAP algorithm is derived for the Non-binary convolutional turbo code, which follows the specifications of turbo coding/decoding in the DVB standard, for twelve...
In order to allow maximum exploitation of the frequency spectrum, the current trend is to increase the spectrum efficiency by using high modulation techniques e.g. multilevel quadrature amplitude modulation (QAM). The use of High Power Amplifiers (HPA), e.g., TWT, in satellite communications channels causes severe nonlinear distortions to the transmitted signal. The transmitted signal is more sensitive...
This paper proposes a simple method to calculate the probability of error (POE) of 16-star (8,8) QAM constellations over nonlinear channels. The method does not need to find the decision regions for each constellation, which is often difficult to find. It does not need also any numerical calculation to evaluate integrations that appear in general when we need to calculate the exact probability of...
Next generation millimeter-wave multimedia satellites will require active antenna arrays capable of providing reconfigurable multibeam operation. The successful deployment of these systems will depend on new active array technologies capable of controlling and combining the performance of hundreds or thousands of elements. A promising approach involves the use of a periodic coplanar leaky-wave antenna...
An important characteristic of turbo codes is the iterative nature of their decoder. One of the factors in determining the performance of turbo decoder is the number of iterations that is used for decoding each input sequence (frame). Using more iterations means decoding more sequences correctly. For example a decoder with 6 iterations per frame is not capable of decoding sequences that may be corrected...
Mobile web browsing is becoming very popular with the recent advances in the satellite and wireless networks, and the growing popularity of the World Wide Web. The mobile users generally have limited resources, such as low bandwidth and low-resolution terminal, compared to the conventional desktop users. It is important to develop techniques that will enable the mobile users to access the web efficiently...
This paper presents a microstrip ring resonator design which exhibits suppressed harmonic excitation and high quality factor. The resonator is constructed from four quarter-wave coupled-line couplers, connected in a square configuration. Of interest is the change in the frequency response of the ring when corrugated couplers are used in place of ordinary couplers. By direct comparison it is shown...
The Space Robotics Group at the CSA is currently working on the design of small rovers for Mars' exploration. These small vehicles will be able to cover large distances from their landing site and will require some kind of localization system.
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