An improved method to design QPSK Balanced Space-Time Trellis Codes

International audienceRecently, a new class of Space-Time Trellis Codes was proposed as having the best performance. These codes are 'balanced' because they use the points of the constellation with the same probability. In this correspondence, we propose a new and simpler method than exisiting method to design these class for QPSK modulation and several transmit antennas. New and better balanced codes for 3 and 4 transmit antennas are also proposed

Implementable Wireless Access for B3G Networks - III: Complexity Reducing Transceiver Structures

This article presents a comprehensive overview of some of the research conducted within Mobile VCE’s Core Wireless Access Research Programme,1 a key focus of which has naturally been on MIMO transceivers. The series of articles offers a coherent view of how the work was structured and comprises a compilation of material that has been presented in detail elsewhere (see references within the article). In this article MIMO channel measurements, analysis, and modeling, which were presented previously in the first article in this series of four, are utilized to develop compact and distributed antenna arrays. Parallel activities led to research into low-complexity MIMO single-user spacetime coding techniques, as well as SISO and MIMO multi-user CDMA-based transceivers for B3G systems. As well as feeding into the industry’s in-house research program, significant extensions of this work are now in hand, within Mobile VCE’s own core activity, aiming toward securing major improvements in delivery efficiency in future wireless systems through crosslayer operation

Improved Balanced 2n-PSK STTCs for Any Number of Transmit Antennas from a New and General Design Method

ISBN: 978-1-4244-2517-4International audienceRecently, it has been established that the best space- time trellis codes (STTCs) belong to a specific class of codes. The codes of this class are called "balanced STTCs" because they use the points of the MIMO constellation with the same probability. Therefore, the search of the best codes can be reduced to this class. This paper presents a new and general method to design 2n-PSK balanced STTCs for any number of transmit antennas. This method is simpler than the first method, which was described only for 4-PSK modulation and can be generalized for any configuration of the space-time trellis encoder. Simulation results of new 4-PSK and 8-PSK balanced codes prove the importance of this class

4-PSK Balanced STTC with Two Transmit Antennas

International audienceIn this paper we introduce a new class of space-time trellis codes (STTC). We call them Balanced STTC (B-STTC) because the points of the constellation are used with the same probability. Comparing to known codes, the balanced codes offer the best performance. Therefore, the systematic search for good codes can be reduced to this class. We present here the design of the 4-PSK balanced STTC with 2 transmit antennas. A complete list of the best 4-state and several 16-state good balanced codes are also given

4-PSK Balanced STTC with Two Transmit Antennas

International audienceIn this paper we introduce a new class of space-time trellis codes (STTC). We call them Balanced STTC (B-STTC) because the points of the constellation are used with the same probability. Comparing to known codes, the balanced codes offer the best performance. Therefore, the systematic search for good codes can be reduced to this class. We present here the design of the 4-PSK balanced STTC with 2 transmit antennas. A complete list of the best 4-state and several 16-state good balanced codes are also given

Space-Time Signal Design for Multilevel Polar Coding in Slow Fading Broadcast Channels

Slow fading broadcast channels can model a wide range of applications in wireless networks. Due to delay requirements and the unavailability of the channel state information at the transmitter (CSIT), these channels for many applications are non-ergodic. The appropriate measure for designing signals in non-ergodic channels is the outage probability. In this paper, we provide a method to optimize STBCs based on the outage probability at moderate SNRs. Multilevel polar coded-modulation is a new class of coded-modulation techniques that benefits from low complexity decoders and simple rate matching. In this paper, we derive the outage optimality condition for multistage decoding and propose a rule for determining component code rates. We also derive an upper bound on the outage probability of STBCs for designing the set-partitioning-based labelling. Finally, due to the optimality of the outage-minimized STBCs for long codes, we introduce a novel method for the joint optimization of short-to-moderate length polar codes and STBCs

Optimal Generation of Space-Time Trellis Codes via Coset Partitioning

International audienceCriteria to design good space-time trellis codes (STTCs) have been already developed in previous publications. However, the computation of the best STTCs is time-consuming because a long exhaustive or systematic computing search is required, especially for a high number of states and/or transmit antennas. In order to reduce the search time, an efficient method must be employed to generate the STTCs with the best performance. In this paper, a technique called coset partitioning is proposed to design easily and efficiently optimal 2^n-PSK STTCs with any number of transmit antennas. The coset partitioning is an improved extension to multiple input multiple output (MIMO) systems of the set partitioning proposed by Ungerboeck. This extension is based on the lattice and coset Calderbank's approach. With this method, optimal blocks of the generator matrix are obtained for 4-PSK and 8-PSK codes. These optimal blocks lead to the generation of the STTCs with the best Euclidean distances between the codewords. Thus, new codes are proposed with 3 to 6 transmit antennas for 4-PSK modulation and with 3 and 4 transmit antennas for 8-PSK modulation. These new codes outperform the corresponding best known codes. Besides, the first 4-PSK STTCs with 7 and 8 transmit antennas and the first 8-PSK STTCs with 5 and 6 transmit antennas are given and their performance is evaluated by simulation

Performance Analysis Of A Cellular System Using C-Ofdm Techniques

The basic idea of COFDM is to split the modulation samples of incoming data stream onto a large number of carriers instead of modulating a unique carrier. Therefore, COFDM is an effective technique for combating multi-path fading and for highbit- rate transmission over wireless channel. In a single carrier system a frequency Selective fading can cause the entire transmission link to fail, but in an COFDM multi carrier system, only a small percentage of the sub-carriers will be corrupted. Frequency and time interleaving in conjunction with forward error correction coding can then be used to correct for erroneous subcarriers. The background information with the aim to provide an intuitive explanation of our research motivation. C-OFDM is the modulation scheme of choice , as enshrined in International standard for all forms of digital broadcasting both audio and video and including satellite, terrestrial, and cable. In the existing standard the “coding” referred to consists of an inner convolutional code concatenated with an outer R-S code; here in this thesis, we replace the inner code with the coding like space time trellis code for analysi

New Method to Generate Balanced 2n-PSK STTCs

The first theoretical bases of the space-time trellis codes (STTCs) have been established by Tarokh (1998). Many STTCs have been published using several criteria proposed by Tarokh (1998) and Chen (2001) for slow and fast Rayleigh fading channels. More recently, a new class of codes called balanced codes, which contains all the best STTCs has been presented by Ngo (2007, 2008). These balanced codes have the same property: if the data are generated by a binary memoryless source with equally probable symbols, the used points of the MIMO constellation are generated with the same probability. Therefore, the systematic search for the best codes can be reduced to this class. Thus, the time to find the best codes is reduced. The new and general method is proposed to design balanced 2^n-PSK STTCs for several transmit antennas. This new method is simpler and faster than the previous one presented by Ngo 2007 in particular when the number of transmit antennas and n increase