We propose a generalization of Rank modulation (RM) scheme, Compressed Rank modulation (CRM) scheme for nonvolatile memories. CRM stores information in the multiset permutation induced by the charge levels of N = Sigm...
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ISBN:
(纸本)9781467345392;9781467345378
We propose a generalization of Rank modulation (RM) scheme, Compressed Rank modulation (CRM) scheme for nonvolatile memories. CRM stores information in the multiset permutation induced by the charge levels of N = Sigma(n)(i=1) m(i) cells: set the ranks of the first m(1) highest charge level cells as 1, the ranks of the next m(2) highest charge level cells are 2, and the ranks of the last m(n) highest charge level cells are n. The only allowed charge-placement method is the minimal-push-up aiming to minimize the increase of highest charge levels, and such minimization of highest charge level increase is defined as rewriting cost. CRM achieves a higher capacity comparing with RM, and maintains its advantages meanwhile. The closed-form formula for rewriting cost, sizes of balls, asymptotical rate analysis for rewriting codes, and one rewriting code construction are presented.
We consider rank modulation codes for flash memories that allow for handling arbitrary charge drop errors. Unlike classical rank modulation codes used for correcting errors that manifest themselves as swaps of two adj...
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ISBN:
(纸本)9781467325790
We consider rank modulation codes for flash memories that allow for handling arbitrary charge drop errors. Unlike classical rank modulation codes used for correcting errors that manifest themselves as swaps of two adjacently ranked elements, the proposed translocation codes account for more general forms of errors that arise in storage systems. Translocations represent a natural extension of the notion of adjacent transpositions and as such may be analyzed using related concepts in combinatorics and rank modulation coding. Our results include deriving the asymptotic capacity of translocation rank codes, construction techniques for asymptotically good codes and a simple decoding algorithm.
Recently, the concept of the cooperative communications has been applied extensively for the ultra-wideband (UWB) system. In this paper, the cooperative scheme of the noncoherent UWB impulse radio system with block-co...
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ISBN:
(纸本)9781467313568
Recently, the concept of the cooperative communications has been applied extensively for the ultra-wideband (UWB) system. In this paper, the cooperative scheme of the noncoherent UWB impulse radio system with block-coded modulation (BCM) having a codeword matching and signal aggregation (CMSA) detection is discussed under different fading environments, which has not been studied yet. To enlarge the operation range of the USB system, the amplify-and-forward scheme is used as a relay protocol to re-transmit signals from source to destination. Simulation results illustrate that the proposed method performs better than that without a cooperative scheme over the Nakagami-m fading channel.
With an eye toward coded transmission of high-level modulation on satellite links, we study the information-theoretic potential of nonlinear satellite channels, for both single-user per transponder operation and simul...
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ISBN:
(纸本)9781467350808;9781467350792
With an eye toward coded transmission of high-level modulation on satellite links, we study the information-theoretic potential of nonlinear satellite channels, for both single-user per transponder operation and simultaneous two-way, on-frequency relaying to improve spectrum efficiency as much as 100%. We develop an analytic nonlinear model with finite memory for these two scenarios, and compute achievable rate regions, i.e. information rates that are arbitrarily reliable, as a function of link SNR's and input backoff of the nonlinear amplifier. This provides guidance on required SNR and desired amplifier operating point for advanced coded modulation schemes.
This paper presents a novel design of linear random space time coding (LRSTC) scheme. This scheme is able to achieve the dual benefits for MIMO receiver rate adaptation: (1) rateless coding and modulation and (2) appr...
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ISBN:
(纸本)9781457720536
This paper presents a novel design of linear random space time coding (LRSTC) scheme. This scheme is able to achieve the dual benefits for MIMO receiver rate adaptation: (1) rateless coding and modulation and (2) approximately universal tradeoff between diversity gain and multiplexing gain. In this scheme, an LRSTC symbol is the superposition of a block of randomly rotated QPSK symbols. Such superposition generates a dense constellation that ensures a high saturation rate. The random rotation guarantees the pseudo-orthogonality between QPSK symbols. Through utilizing the orthogonality of symbols, a power gain can be generated at receiver end. The power gain can be increased by transmitting more LRSTC symbols to the receiver in order to resist stronger noise of the MIMO system. Therefore, the rate can be seamlessly adapted through varying the number of transmitted symbols rather than the adopting conventional strategies in terms of modulation, coding and antenna selection. Moreover, the transmission of LRSTC symbols will span over all of the transmit antennas which allows the spatial diversity to be fully exploited. When the rank of MIMO matrix is greater than 1, more linear independent symbols can be received in each time slot. Hence, multiplexing gain can also be achieved. We have carried out both analysis and simulations to verify this LRSTC design. The simulation results show that LRSTC not only achieves the throughput comparable with the ideal conventional rate adaptation, but also accomplishes a seamless switching between diversity and multiplexing gain.
This paper presents a novel scheme of low-densityparity- check (LDPC) coded modulation system called bit-expandinterleaved coded modulation with iterative decoding and demapping (BEICM-ID) over Rayleigh fading channel...
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ISBN:
(纸本)9781467358293;9781467358309
This paper presents a novel scheme of low-densityparity- check (LDPC) coded modulation system called bit-expandinterleaved coded modulation with iterative decoding and demapping (BEICM-ID) over Rayleigh fading channels. In traditional bit-interleaved coded modulation (BICM) schemes and its iterative version, BICM-ID, each bit node is mapped into one single symbol, but in our new BEICM-ID scheme some bit nodes may map into multi symbols, thus diversity is achieved, and since iterative decoding and demapping is used, more mutual information will exchange among bit nodes, check nodes and symbol nodes which may further improve the total error correcting ability. Compared to the BICM and BICM-ID schemes, the proposed coded modulation scheme can achieve a performance gain with different modulation types under Rayleigh fading channels, with 256qam modulation the gain over BICM is about 1.5dB and the gain over BICM-ID is about 0.75dB.
In this paper, we investigate designing of hybrid free space optical (FSO)/radio frequency (RF) symbol mappers using bit-interleaved coded modulation with iterative decoding (BICM-ID) with asymmetric data rates betwee...
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ISBN:
(纸本)9781467309219;9781467309202
In this paper, we investigate designing of hybrid free space optical (FSO)/radio frequency (RF) symbol mappers using bit-interleaved coded modulation with iterative decoding (BICM-ID) with asymmetric data rates between the FSO and the RF links. Data bits are first encoded with a channel code and the coded bits after an interleaver are mapped to hybrid FSO/RF symbols instead of separate conventional RF symbols and on-off keyed FSO transmissions. Iterative decoding is used at the receiver. An orthogonal evolutionary (OE) algorithm to obtain optimal symbol mappings is used. Two cost functions to be used in the OE algorithm are proposed. For high signal-to-noise ratio (SNR) regime, analytical error bound expressions are used and at the low SNR regime, extrinsic information transfer (EXIT) chart is used for the cost function. The proposed mappings achieve significant gains over conventional mappings. For a hybrid FSO/RF link with an FSO and RF channel use ratio of 10:1, the proposed mapping achieves an optical SNR gain of more than 7 dB over conventional mapping. A good agreement between simulation and analysis results is obtained for the proposed scheme at high SNR.
This paper proposes a codeword-based iterative detecting and decoding (IDD) algorithm using a rank-reduced maximum likelihood (ML) detector with pre-whitened interference over multiple-input multiple-output (MIMO) cha...
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ISBN:
(纸本)9781467318792
This paper proposes a codeword-based iterative detecting and decoding (IDD) algorithm using a rank-reduced maximum likelihood (ML) detector with pre-whitened interference over multiple-input multiple-output (MIMO) channels. This iterative algorithm operates on the principle of successive interference cancelation (SIC) where all the layers per codeword are decoded together at each iteration. The recent wireless standard requires to encode data bits per codeword, not per layer at multiple antennas. Thus, SIC algorithms based on layer-separating detectors could lose joint information between layers in a single codeword. Instead, the proposed algorithm minimizes this loss by using rank-reduced ML detectors over soft feedback. Simulations are performed on a space-time bit-interleaved coded modulation over Rayleigh fading channels, and demonstrate the proposed SIC algorithm is superior to comparable iterative and non-iterative IDD algorithms.
A completely automated system has been designed to calibrate path delays in a two way satellite time and frequency transfer (TWSTFT) ground station. The heart of this delay calibration system is a dual bidirectional u...
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ISBN:
(纸本)9781467319232
A completely automated system has been designed to calibrate path delays in a two way satellite time and frequency transfer (TWSTFT) ground station. The heart of this delay calibration system is a dual bidirectional up/down converter that converts the modulated pseudo random noise (PRN) code from 70 MHz to Ku-band (10 GHz to 14 GHz) frequencies and vice versa. Besides the usual transmit (Tx) and receive (Rx) paths in the TWSTFT system, the dual bi-directional up/down converter offers two additional independent transmit and receive paths. These additional paths allow performing different independent loop delay measurements within the station from which the individual path delays can be calculated.
An RDS-minimizing, multi-mode modulation coding scheme, using maximum run-length violating markers and based on the Knuth balancing approach, is applied to run-length limited sequences. Simulations are used to measure...
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ISBN:
(纸本)9781467302234;9781467302241
An RDS-minimizing, multi-mode modulation coding scheme, using maximum run-length violating markers and based on the Knuth balancing approach, is applied to run-length limited sequences. Simulations are used to measure spectra and DC suppression performance. A comparison to EFM is included.
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