Entropy Coding Aided Adaptive Subcarrier-Index Modulated OFDM

Kadir, Mohammad Ismat; Zhang, Hongming; Chen, Sheng; Hanzo, Lajos

doi:10.1109/access.2018.2801561

“…• Different from the adaptive Huffman coded OFDM-IM schemes proposed in [23] and [24] that focus on the optimization of the architecture of the Huffman tree, we instead focus on the optimization of the bijective mapping relation between all legitimate SAPs and leaves on a given Huffman tree, i.e., the variable-length bit sequences. Therefore, EHC-OFDM-IM can be applied on top of the optimized systems constructed in [23] and [24] to further enhance their error performance.…”

Section: Introductionmentioning

confidence: 99%

“…over {G n (ξ n )} N n=1 when the allocated power for active subcarriers is independent of H, which yields(23), where (a) follows from by the independence among subcarriers and Γ( ) = ∞ 0 u −1 exp(−u)du is the complete gamma function. Substituting(23) into(17) gives the approximate BLER when x(s, m) is transmitted.Finally, according to(6),(14) and the Huffman encoding rules, it is evident that there exist M K legitimate OFDM blocks adopting the same SAP. Hence, it is straightforward to explicitly express the average BLER asPe = 1 M K x(s,m)∈X p(s)P e (x(s, m)).(24)V.…”

mentioning

confidence: 99%

Enhanced Huffman Coded OFDM With Index Modulation

Dang

¹

,

Guo

²

,

Coon

³

et al. 2020

IEEE Trans. Wireless Commun.

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In this paper, we propose an enhanced Huffman coded orthogonal frequency-division multiplexing with index modulation (EHC-OFDM-IM) scheme. The proposed scheme is capable of utilizing all legitimate subcarrier activation patterns (SAPs) and adapting the bijective mapping relation between SAPs and leaves on a given Huffman tree according to channel state information (CSI). As a result, a dynamic codebook update mechanism is obtained, which can provide more reliable transmissions.We take the average block error rate (BLER) as the performance evaluation metric and approximate it in closed form when the transmit power allocated to each subcarrier is independent of channel states.Also, we propose two CSI-based power allocation schemes with different requirements for computational complexity to further improve the error performance. Subsequently, we carry out numerical simulations to corroborate the error performance analysis and the proposed dynamic power allocation schemes. By studying the numerical results, we find that the depth of the Huffman tree has a significant impact on the error performance when the SAP-to-leaf mapping relation is optimized based on CSI. Meanwhile, through numerical results, we also discuss the trade-off between error performance and data transmission rate and investigate the impacts of imperfect CSI on the error performance of EHC-OFDM-IM.Orthogonal frequency-division multiplexing with index modulation (OFDM-IM), Huffman coding, dynamic codebook design, power allocation, channel state information (CSI).both provide good thoughts on how the Huffman tree architecture could be adapted to provide a higher capacity and transmission rate when utilizing all legitimate SAPs. In [25], Huffman coding was applied to OFDM-IM with the help of channel state information (CSI). However, the Huffman coded OFDM-IM scheme proposed in [25] did not fully exploit all legitimate SAPs, and thereby only shows limited improvements. The latest research results with respect to the optimization of the achievable rate of binary-tree coded OFDM-IM (a generic version of Huffman coded OFDM-IM) were presented in [26]. In this work, the achievable rate is optimized by dynamically varying the SAP probability distribution and transmit power allocated to active subcarriers. January 7, 2020 DRAFT

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“…• Different from the classic Huffman coded OFDM-IM scheme proposed in [22] that does not rely on any channel feedback, we employ CSI at the transmitting side to provide an adaptive optimization mechanism. • Different from the adaptive Huffman coded OFDM-IM schemes proposed in [23] and [24] that focus on the optimization of the architecture of the Huffman tree, we instead focus on the optimization of the bijective mapping relation between all legitimate SAPs and leaves on a given Huffman tree, i.e., the variable-length bit sequences. Therefore, EHC-OFDM-IM can be applied on top of the optimized systems constructed in [23] and [24] to further enhance their error performance.…”

Section: Introductionmentioning

confidence: 99%

Enhanced Huffman Coded OFDM with \\Index Modulation

Dang¹,

Guo²,

Coon³

et al. 2020

Preprint

0

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In this paper, we propose an enhanced Huffman coded orthogonal frequency-division multiplexing with index modulation (EHC-OFDM-IM) scheme. The proposed scheme is capable of utilizing all legitimate subcarrier activation patterns (SAPs) and adapting the bijective mapping relation between SAPs and leaves on a given Huffman tree according to channel state information (CSI). As a result, a dynamic codebook update mechanism is obtained, which can provide more reliable transmissions. We take the average block error rate (BLER) as the performance evaluation metric and approximate it in closed form when the transmit power allocated to each subcarrier is independent of channel states. Also, we propose two CSI-based power allocation schemes with different requirements for computational complexity to further improve the error performance. Subsequently, we carry out numerical simulations to corroborate the error performance analysis and the proposed dynamic power allocation schemes. By studying the numerical results, we find that the depth of the Huffman tree has a significant impact on the error performance when the SAP-to-leaf mapping relation is optimized based on CSI. Meanwhile, through numerical results, we also discuss the trade-off between error performance and data transmission rate and investigate the impacts of imperfect CSI on the error performance of EHC-OFDM-IM.Index Terms-Orthogonal frequency-division multiplexing with index modulation (OFDM-IM), Huffman coding, dynamic codebook design, power allocation, channel state information (CSI).

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“…To address these issues related to the mapping of source bit sequences to permutation patterns, a few recent contributions have focused on the adaptation of binary Huffman coding [19] for permutation/index codebook design [11], [17], [20]- [23]. Here, a bijective mapping between information bit sequences and the permutation/index patterns is constructed with the aid of a full binary tree; patterns are associated with leaves in the tree, and corresponding bit sequences are defined according to a labeling rule (used in the Huffman algorithm) pertaining to the respective paths from each leaf to the root.…”

Section: Introductionmentioning

confidence: 99%

“…Binary-tree encoding for permutation modulation schemes enables one to choose the probability distribution of the arXiv:1901.01736v1 [cs.IT] 7 Jan 2019 permutation patterns to achieve certain design criteria, e.g., achievable rate maximization [11], [17], [21], [23] or symbolerror rate (SER) minimization [21], [23]. However, existing works along this direction fall short in a number of ways.…”

Section: Introductionmentioning

confidence: 99%

Binary-Tree Encoding for Uniform Binary Sources in Index Modulation Systems

Coon

¹

,

Badiu

²

,

Liu

³

et al. 2019

IEEE J. Sel. Top. Signal Process.

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The problem of designing bit-to-pattern mappings and power allocation schemes for orthogonal frequency-division multiplexing (OFDM) systems that employ subcarrier index modulation (IM) is considered. We assume the binary source conveys a stream of independent, uniformly distributed bits to the pattern mapper, which introduces a constraint on the pattern transmission probability distribution that can be quantified using a binary tree formalism. Under this constraint, we undertake the task of maximizing the achievable rate subject to the availability of channel knowledge at the transmitter. The optimization variables are the pattern probability distribution (i.e., the bit-to-pattern mapping) and the transmit powers allocated to active subcarriers. To solve the problem, we first consider the relaxed problem where pattern probabilities are allowed to take any values in the interval [0, 1] subject to a sum probability constraint. We develop (approximately) optimal solutions to the relaxed problem by using new bounds and asymptotic results, and then use a novel heuristic algorithm to project the relaxed solution onto a point in the feasible set of the constrained problem. Numerical analysis shows that this approach is capable of achieving the maximum mutual information for the relaxed problem in low and high-SNR regimes and offers noticeable benefits in terms of achievable rate relative to a conventional OFDM-IM benchmark.

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Entropy Coding Aided Adaptive Subcarrier-Index Modulated OFDM

Cited by 15 publications

References 47 publications

Enhanced Huffman Coded OFDM With Index Modulation

Enhanced Huffman Coded OFDM With Index Modulation

Enhanced Huffman Coded OFDM with \\Index Modulation

Binary-Tree Encoding for Uniform Binary Sources in Index Modulation Systems

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