Top PDF Signal mapping designs for bit-interleaved coded modulation with iterative decoding (BICM-ID)

Signal mapping designs for bit-interleaved coded modulation with iterative decoding (BICM-ID)

Signal mapping designs for bit-interleaved coded modulation with iterative decoding (BICM-ID)

December, 2004 ABSTRACT Bit-interleaved coded modulation with iterative decoding (BICM-ID) is a spectral ef- ficient coded modulation technique to improve the performance of digital communica- tion systems. It has been widely known that for fixed signal constellation, interleaver and error control code, signal mapping plays an important role in determining the error performance of a BICM-ID system. This thesis concentrates on signal mapping designs for BICM-ID systems. To this end, the distance criteria to find the best map- ping in terms of the asymptotic performance are first analytically derived for different channel models. Such criteria are then used to find good mappings for various two- dimensional 8-ary constellations. The usefulness of the proposed mappings of 8-ary constellations is verified by both the error floor bound and simulation results.
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Performance of combined constellation shaping and bit interleaved coded modulation with iterative decoding (BICM-ID)

Performance of combined constellation shaping and bit interleaved coded modulation with iterative decoding (BICM-ID)

Abstract. The increasing demand of achieving high data rates in modern communication systems requires highly ef- ficient bandwidth utilization. For this purpose, multilevel modulation schemes are used in association with forward er- ror correction (FEC) codes in order to approach the channel capacity. However, there is a gap between the capacity of a uniform signal constellation and the Shannon unconstrained capacity. This gap can be reduced by applying constella- tion shaping. The task of shaping is to modify a uniform distributed signal constellation towards a Gaussian like dis- tribution. In this paper, we investigate different approaches to combine the constellation shaping with a bit interleaved coded modulation with iterative decoding (BICM-ID) sys- tem. Simulation results show that this combination can offer a shaping gain up to 0.6 dB.
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On Bit-interleaved Coded Modulation with QAM Constellations

On Bit-interleaved Coded Modulation with QAM Constellations

Bit-interleaved coded modulation (BICM) is a flexible modulation/coding scheme which allows the designer to choose a modulation constellation independently of the coding rate. This is because the output of the channel encoder and the input to the modulator are separated by a bit-level interleaver. In order to increase spectral efficiency, BICM can be combined with high-order modulation schemes such as quadrature amplitude modulation (QAM) or phase shift keying. BICM is particularly well suited for fading channels, and it only introduces a small penalty in terms of channel capacity when compared to the coded modulation capacity for both additive white Gaussian noise and fading channels. Additionally, if the so-called BICM with iterative decoding (BICM-ID) is used, the demapper and decoder iteratively exchange information, improving the system performance.
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Two Way Relaying Communications with OFDM and BICM/BICM-ID

Two Way Relaying Communications with OFDM and BICM/BICM-ID

As listed above, techniques are developed to achieve the different types of diversity gains and all schemes are designed for system without considering forward error correction (FEC). Bit-interleaved coded modulation (BICM) is a technique first proposed in [13] which uses convolutional encoder/decoder and bit interleaver/de-interleaver to achieve potential diver- sity gains. Later, [14] gives an analytic framework of BICM and presents the design criterion which treats coding and modulation as separate components. By selecting the convolutional code with large free Hamming distance and designing interleaver with enough interleave depth, BICM is able to achieve any types of diversity gains. Specifically, references [13, 14] assume fast fading scenario where time diversity gains are achieved by using BICM. Then in [12, 15], BICM is combined with OFDM to obtain the multipath diversity gains. In multiple-input multiple-output (MIMO) systems, BICM is also able to exploit the space diversity gains [16, 17]. To further enhance the performance of BICM system, iterative processing is introduced in BICM systems and it is called BICM with iterative decoding (BICM-ID). Reference [18] first proposed the iterative processing between the demodulator and the decoder and shows that it can provide a significant performance gain over BICM systems.
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Luby Transform Coding Aided Bit Interleaved Coded Modulation for the Wireless Internet

Luby Transform Coding Aided Bit Interleaved Coded Modulation for the Wireless Internet

Abstract— Bit-Interleaved Coded Modulation using Iterative Decoding (BICM-ID) is amalgamated with Luby Transform (LT) coding. The resultant joint design of the physical and data link layer substantially improves the attainable Bit Error Rate (BER) performance. A Cyclic Redundancy Check (CRC) combined with a novel Log-Likelihood Ratio (LLR) based packet reliability estimation method is proposed for the sake of detecting and disposing of erroneous packets. Subsequently, bit-by-bit LT decoding is proposed, which facilitates a further BER improvement at a lower number of BICM-ID iterations. Finally, we revisit the pseudo random generator function used for designing the LT generator matrix.
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On Bit-interleaved Coded Modulation with QAM Constellations

On Bit-interleaved Coded Modulation with QAM Constellations

Abstract Bit-interleaved coded modulation (BICM) is a flexible modulation/coding scheme which allows the designer to choose a modulation constellation independently of the coding rate. This is because the output of the channel encoder and the input to the modulator are separated by a bit-level interleaver. In order to increase spectral efficiency, BICM can be combined with high-order modulation schemes such as quadrature amplitude modulation (QAM) or phase shift keying. BICM is particularly well suited for fading channels, and it only introduces a small penalty in terms of channel capacity when compared to the coded modulation capacity for both additive white Gaussian noise and fading channels. Additionally, if the so-called BICM with iterative decoding (BICM-ID) is used, the demapper and decoder iteratively exchange information, improving the system performance.
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Irregular 8PSK mapping for variable length codes with small blocks in a BICM ID system

Irregular 8PSK mapping for variable length codes with small blocks in a BICM ID system

Iterative decoding is an effective technique to approach the channel capacity for very large block sizes with enough iterations. However, due to the limitation of bandwidth and delay, small blocks of data are much more commonly applied in practical communications, and low iteration counts are usually preferred for both decoding complexity and delay consideration. In such cases, the design rules of near capacity decoding—which is generally asymptotic with respect to the block size—may cause inferior performance. To overcome this problem for 8-phase shift keying (8PSK) modulated variable length codes (VLCs), an irregular mapping scheme for the transmission system of bit-interleaved coded modulation with iterative decoding (BICM-ID) is studied in this paper. A submapping searching algorithm and an irregular mapping optimization algorithm are proposed aiming at maximizing the extrinsic mutual information after a target number of iterations. Simulation results show that for small data block size with a low iteration count, our scheme has advantages with respect to the existing near capacity systems optimized by the asymptotic tools.
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Mapping Design for 2M -Ary Bit-Interleaved Polar Coded Modulation

Mapping Design for 2M -Ary Bit-Interleaved Polar Coded Modulation

In a high-order BICM scheme, as the minimum Euclidean distance for each modulation level is different, all bits within a transmitted symbol get unequal protections from the modulator [15]. A properly designed mapping rule between the encoder and the modulator can lead to significant per- formance improvement for the BIPCM scheme [3]. Besides, stopping set in the factor graph of code, is an important cause of the decoding failure with BP decoding [16]. In [17], Eslami et al. analyzed stopping sets for polar code and their effects on the performance of BP decoding. This property for polar codes over the factor graph has been well utilized to improve the performance of iterative decoding [17]–[21]. Motivated by these observations, in this paper we consider the mapping design for the BIPCM scheme with BP decoding taking both the properties of polar codes over the factor graph and the unequal error protection property of high-order modulations into account.
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Optimization of irregular mapping for error floor removed bit interleaved coded modulation with iterative decoding and 8PSK

Optimization of irregular mapping for error floor removed bit interleaved coded modulation with iterative decoding and 8PSK

Bit-interleaved coded modulation (BICM) [1,2] is the serial concatenation of a channel encoder, a bitwise inter- leaver, and a symbol mapper. It is a bandwidth-efficient approach primarily considered for fading channels, which increases the time diversity of coded modulation and yields a better coding gain over Rayleigh fading chan- nels than trellis-coded modulation (TCM). The perfor- mance of BICM can be greatly improved through iterative decoding (ID), which is an effective technique to improve decoding performances. The BICM with iterative decod- ing (BICM-ID) [3-5] takes advantages of iterative infor- mation exchanges between the demapper and the channel decoder and provides excellent performances over both additive white Gaussian noise (AWGN) and Rayleigh fad- ing channels.
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Design, implementation and prototyping of an iterative receiver for bit-interleaved coded modulation system dedicated to DVB-T2

Design, implementation and prototyping of an iterative receiver for bit-interleaved coded modulation system dedicated to DVB-T2

which includes a real demodulator, channel emulator and the demodulator. Promising results have shown the efficiency of the demapper and the LDPC decodere. Afterwards, we have proposed a joint vertical shuffled iterative demapping and decoding algorithm to reduce the processing latency of an iterative receiver. The main idea of our proposal relies on dividing the whole frame into sub-frames and applying iterative processing on every sub-frame. This is achieved by using vertical shuffled LDPC decoding to provide a fast generation of extrinsic information and by using a Look-Up-Table based interleaving/de- interleaving to provide a fast routing of information between the demapper and the decoder. The message exchange schedules have been investigated. An efficient schedule that is suit- able for hardware implementation has been detailed and the corresponding shuffled parallel iterative BICM receiver has been designed and implemented onto an emulation board for QPSK constellation as a first step. The design of this iterative receiver takes up around 50% of hardware resources in terms of RAM and logic slice of a Xilinx Virtex 5 LX330 device. The estimated maximum working frequency of the receiver is 80Mhz, that results to a throughput of 107 Mbps for 64K LDPC with a code rate of R=4/5. The measured performance achieves expected performance gains, which validate the efficiency of our proposal. To the best of our knowledge, this is the first hardware implementation of a BICM-ID receiver for the DVB-T2 standard.
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Design and FPGA prototyping of a bit-interleaved coded modulation receiver for the DVB-T2 standard

Design and FPGA prototyping of a bit-interleaved coded modulation receiver for the DVB-T2 standard

For a BICM-ID scheme, an efficient exchange of extrinsic information between the demapper and the decoder has to be applied. Indeed, the ID imposes a latency that can have an important impact on the whole receiver. Shuffled versions of the standard iterative decoding algorithms for both LDPC and turbo codes are presented in [11]. The proposed schemes have about the same computational complexity as the standard versions while enjoying faster iterative process convergence. This principle can be extended to BICM-ID in order to design a low-latency receiver. It forces however a vertical layered schedule for the decoding of the LDPC codes. Vertical layered schedule for the BP algorithm is found in literature. To our knowledge, normalized MS based on vertical layered decoding was only studied in [12]. Moreover, the problem of memory access conflicts for layered architectures has never been addressed in the case of a normalized MS based on vertical layered decoding. As a possible solution, we extend the reordering mechanism of the DVB-T2 parity check matrix detailed in [13], to a vertical layered schedule. We also solved the message updating inefficiency caused by the double diagonal sub-matrices during the decoder design. The remainder of the paper is organized as follows. Section 2 recalls the basic principles of the BICM-ID and SSD. Section 3 details a vertical layered decoding using a normalized MS algorithm. The challenging issue of resolving memory conflicts is developed in Section 4. Finally, an implementation of the proposed LDPC decoder for a BICM receiver and its experimental setup onto an FPGA device are presented.
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Bit-Interleaved Coded Modulation

Bit-Interleaved Coded Modulation

In contrast to Ungerb¨ ock’s findings, Zehavi proposed bit-interleaved coded modulation (BICM) as a pragmatic approach to coded modula- tion. BICM separates the actual coding from the modulation through an interleaving permutation [142]. In order to limit the loss of infor- mation arising in this separated approach, soft information about the coded bits is propagated from the demodulator to the decoder in the form of bit-wise a posteriori probabilities or log-likelihood ratios. Ze- havi illustrated the performance advantages of separating coding and modulation. Later, Caire et al. provided in [29] a comprehensive analy- sis of BICM in terms of information rates and error probability, show- ing that in fact the loss incurred by the BICM interface may be very small. Furthermore, this loss can essentially be recovered by using iter- ative decoding. Building upon this principle, Li and Ritcey [64] and ten Brink [122] proposed iterative demodulation for BICM, and il- lustrated significant performance gains with respect to classical non- iterative BICM decoding [29, 142] when certain binary mappings and convolutional codes are employed. However, BICM designs based on convolutional codes and iterative decoding cannot approach the coded modulation capacity, unless the number of states grows large [139]. Improved constructions based on iterative decoding and on the use of powerful families of modern codes can, however, approach the channel capacity for a particular signal constellation [120, 121, 127].
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A Self-Adaptive Decoding Scheme for BICM-ID Embedded Turbo Codes

A Self-Adaptive Decoding Scheme for BICM-ID Embedded Turbo Codes

 In recent years, turbo codes have become a major focus of coding research and applications. They havebeenshowntoperformextremelywellwithcomputationallyefficientiterativedecoding[1,2].Bitinterleavedcodedmodulation(BICM)wasfirstintroducedbyZehavi[3],andfurtherstudiedbyCaire[4] toimprovesystemperformanceoverRayleighfadingchannels.Iterativejointdecodinganddemodulation assisted BICM referred to as BICMID has been proposed [5]. It has been proved as an effective transmissionschemewithoutbandwidthexpansion.
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Serially Concatenated Luby Transform Coding and Bit Interleaved Coded Modulation Using Iterative Decoding for the Wireless Internet

Serially Concatenated Luby Transform Coding and Bit Interleaved Coded Modulation Using Iterative Decoding for the Wireless Internet

A sophisticated serial concatenated LT-BICM-ID scheme was pro- posed, which is capable of improving the BER performance of packe- tized data transmission, when communicating over the AWGN-conta- minated BEC. The concept of using BICM-ID to improve the attain- able BER of the LT codes invoked for correcting the packet errors was the main benefit of the proposed scheme. With the advent of using our proposed improved robust distribution of Section 2.4 and a strong BICM-ID inner code, we demonstrated that our scheme is capable of achieving a better BER performance than that of the classic RS (7,3,2) and LT (10000, 13000) benchmarkers, when communicating over the BEC contaminated by AWGN. This scheme is particularly attractive in a wireless Internet scenario. We elaborated on the joint optimiza- tion of the inner and outer code-rates for the sake of maximizing both the effective throughput and the attainable integrity of the system. Our future research will consider the employment of both binary and non- binary LDPC codes as well as TTCM schemes in dispersive turbo- equalized channels [9].
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Bit-interleaved coded modulation

Bit-interleaved coded modulation

Chapter 6 Conclusion Coding in the signal space is dictated directly by Shannon capacity formula and suggested by the random coding achievability proof. In early days of digital com- munications, modulation and coding were kept separated because of complexity. Modulation and demodulation treated the physical channel, waveform generation, parameter estimation and symbol-by-symbol detection. Error correcting codes were used to undo errors introduced by the physical modulation/demodulation process. This paradigm changed radically with the advent of Coded Modulation. Trellis-coded modulation was a topic significant research activities in the 80’s, for approximately a decade. In the early 90’s, new families of powerful random-like codes, such as turbo-codes and LDPC codes were discovered, along with very effi- cient low-complexity Belief Propagation iterative decoding algorithms [10] which allowed unprecedented performance close to capacity, at least for binary-input channels. Roughly at the same time, bit-interleaved coded modulation emerged as a very simple yet powerful tool to concatenate virtually any binary code to any modulation constellation, with only minor penalty with respect to the traditional joint modulation and decoding paradigm. Therefore, BICM and modern powerful codes with iterative decoding were a natural marriage, and today virtually any modern telecommunication system that seeks high spectral efficiency and high performance, including DSL, digital TV and audio-broadcasting, wireless LANs, WiMax, and next generation cellular systems use BICM as the central component of their respective physical layers.
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EXIT constrained BICM ID design using extended mapping

EXIT constrained BICM ID design using extended mapping

This article proposes a novel design framework, EXIT-constrained binary switching algorithm (EBSA), for achieving near Shannon limit performance with single parity check and irregular repetition coded bit interleaved coded modulation and iterative detection with extended mapping (SI-BICM-ID-EM). EBSA is composed of node degree allocation optimization using linear programming (LP) and labeling optimization based on adaptive binary switching algorithm jointly. This technique achieves exact matching between the Demapper (Dem) and decoder’s extrinsic information transfer (EXIT) curves while the convergence tunnel opens until the desired mutual
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Diversity analysis of bit-interleaved coded multiple beamforming with orthogonal frequency division multiplexing

Diversity analysis of bit-interleaved coded multiple beamforming with orthogonal frequency division multiplexing

Boyu Li, Member, IEEE, and Ender Ayanoglu, Fellow, IEEE Abstract For broadband wireless communication systems, Orthogonal Frequency Division Multiplexing (OFDM) has been combined with Multi-Input Multi-Output (MIMO) techniques. Bit-Interleaved Coded Multiple Beamforming (BICMB) can achieve both spatial diversity and spatial multiplexing for flat fading MIMO channels. For frequency selective fading MIMO channels, BICMB with OFDM (BICMB-OFDM) can be applied to achieve both spatial diversity and multipath diversity, making it an important technique. However, analyzing the diversity of BICMB- OFDM is a challenging problem. In this paper, the diversity analysis of BICMB-OFDM is carried out. First, the maximum achievable diversity is derived and a full diversity condition R c SL ≤ 1 is proved, where R c , S, and L are the code rate, the number of parallel steams transmitted at each subcarrier, and the number of channel taps, respectively. Then, the performance degradation due to the correlation among subcarriers is investigated. Finally, the subcarrier grouping technique is employed to combat the performance degradation and provide multi-user compatibility.
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Iterative decoding of JPEG coded images with channel coding

Iterative decoding of JPEG coded images with channel coding

In JSCC design, the rate-distortion (R-D) method [2] is an analytic approach towards optimal bit rate allocation between source and channel encoders. Several JSCC approaches have been proposed for reliable transmission of still images [3] [4]. Previous research work has concentrated on an optimal joint source-channel rate allocation strategy, which was computa- tionally expensive to be adopted in practical systems. How- ever, these methods do not perform well enough for low channel signal-to-noise ratios (SNRs), although they provide excellent results for moderately distorted channels.
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Iterative Demodulation and Decoding for LDPC Coded Generalized Frequency Division Multiplexing

Iterative Demodulation and Decoding for LDPC Coded Generalized Frequency Division Multiplexing

One of the ideas proposed in chapter 4 to reduced receiver complexity was to feed hard estimates of the transmitted symbols to the SISO demodulator instead of the soft-symbol estimates proposed earlier. That is, given a symbol estimate, it would first be mapped to one of the points in the symbol constellation S. However, it should be noted that choosing hard decision feedback is a tradeoff between re- ceiver complexity and BER performance. In Fig. 5.5, we see that the performance penalty for choosing hard decision decoding is around 0.5 dB, and thus hard deci- sion feedback can be further explored as a method to reduced receiver complexity. Receiver complexities are compared in Table 5.3.
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Comparative Study of TCM, TTCM, BICM and BICM ID Schemes

Comparative Study of TCM, TTCM, BICM and BICM ID Schemes

Figure 6 shows the performance of 64state TCM, 64-state BICM, 8-state TTCM using four iterations and 16-state BICM-ID employing four iterations in an 8PSK scheme over uncorrelated narrow[r]

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