Single-Carrier Frequency Division Multiple Access (SC-FDMA) has been selected as the uplink transmission scheme in the 3GPP Long Term Evolution standard. SC-FDMA has reduced sensitivity to phase noise and a lower Peak...
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Single-Carrier Frequency Division Multiple Access (SC-FDMA) has been selected as the uplink transmission scheme in the 3GPP Long Term Evolution standard. SC-FDMA has reduced sensitivity to phase noise and a lower Peak-to-Average Power Ratio (PAPR) compared to Orthogonal Frequency Division Multiple Access. In this paper we propose joint Tomlinson-Harashima Precoding and transmit power allocation for SC-FDMA. We derive the optimum power allocation for SC-FDMA transmission for both Zero-Forcing (ZF) and Minimum Mean-Square Error (MMSE) LE receivers in order to maximize the achievable data rate subject to constant transmit power. Although this improves the system's performance and offers a 1-2 dB improvement over Frequency-Domain Decision Feedback Equalization (FD-DFE), when the proposed transmit power allocation scheme is combined with decision feedback equalization the system incurs a performance degradation due to error propagation. In this paper we propose a joint implementation of the derived power allocation scheme with THP. Here we show that the system's performance is further improved over both FD-LE and FD-DFE when transmit power allocation is applied.
This paper presents the performance evaluation of phase shift keying technique modulation such as BPSK and QPSK using error correcting code. Three error correcting codes types; Bose-Chaudhuri-Hocquenghem (BCH) code, C...
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This paper presents the performance evaluation of phase shift keying technique modulation such as BPSK and QPSK using error correcting code. Three error correcting codes types; Bose-Chaudhuri-Hocquenghem (BCH) code, Cyclic code and Hamming code were used as the encoder/decoder technique to calculate the bit error rate through an Additive White Gaussian Noise (AWGN) channel. Basically, the performance was determined in term of bit rate error (BER) and signal energy to noise power density ratio (Eb/No). Both BPSK and QPSK were also being compared in the symbol error capability known as t in which expected that the performance is graded in response to the increasing of value of t. All simulations were done using MATLAB R2007b software. In general BCH codes demonstrate best performance than Hamming code and Cyclic code for both BPSK and QPSK.
A modified two-group resource allocation scheme is tested with three channel ordering schemes, a hard decision parallel interference cancellation (HDPIC) scheme and a successive interference cancellation (SIC) scheme ...
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ISBN:
(纸本)9781424463961;9781424463985
A modified two-group resource allocation scheme is tested with three channel ordering schemes, a hard decision parallel interference cancellation (HDPIC) scheme and a successive interference cancellation (SIC) scheme to improve the data rate. Channel ordering ensures channels with the lowest energy requirement are loaded with the higher data rate in the two-group resource allocation scheme but may yield an increased computational load, which affects the feasibility of hardware implementation such as in Femtocells. Furthermore, channel ordering is also needed in SIC schemes to reduce error propagation loss, hence improving detection reliability.
For the additive Gaussian noise channel with average codeword power constraint, sparse superposition codes and adaptive successive decoding is developed. Codewords are linear combinations of subsets of vectors, with t...
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For the additive Gaussian noise channel with average codeword power constraint, sparse superposition codes and adaptive successive decoding is developed. Codewords are linear combinations of subsets of vectors, with the message indexed by the choice of subset. A feasible decoding algorithm is presented. Communication is reliable with error probability exponentially small for all rates below the Shannon capacity.
Among the 4G technologies that managed to impose is the IEEE 802.16e Mobile WiMAX technology. Mobile WiMAX promises to deliver high data rates over wide areas and at vehicular speeds of up to 120 km/h. The performance...
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Among the 4G technologies that managed to impose is the IEEE 802.16e Mobile WiMAX technology. Mobile WiMAX promises to deliver high data rates over wide areas and at vehicular speeds of up to 120 km/h. The performance of such a system is greatly influenced by the type of application desired to be supported, either TCP-based (FTP, web browsing) or UDP-based (video streaming). The current paper proposes to analyze and compare the performance of a fully compliant Mobile WiMAX system operating at 2.3 GHz in a vehicular multipath fading channel (ITU M.1225 Veh.A). The results are generated on a link speed basis and are expressed in terms of the adaptive modulation and coding (AMC) switching points as well as the maximum achievable throughput and operating range. Different physical packet error rate (PER) requirements are considered, based on the quality of service (QoS) level imposed.
coding techniques for reducing peak-to-mean-envelope-power-ratio (PMEPR) have been intensively investigated for the orthogonal frequency division multiplexing (OFDM) systems adopting PSK, square QAM, and rectangular Q...
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coding techniques for reducing peak-to-mean-envelope-power-ratio (PMEPR) have been intensively investigated for the orthogonal frequency division multiplexing (OFDM) systems adopting PSK, square QAM, and rectangular QAM constellations since the PMEPR is the crucial problem in OFDM. Recently, we designed a new coding method for reducing the PMEPR in OFDM built on star 16QAM constellations. In this paper, we present a generalized paradigm for the novel asterisk 16QAM constellations and facilitate the new PMEPR controlling technique for OFDM systems. In this new framework of the asterisk 16QAM (A16QAM) coded OFDM systems, we establish the theoretical development and show that the maximum PMEPR is bounded by 4.0 and 2.0, if the information symbols are coded using Golay sequences and Golay complementary pairs, respectively.
This paper studies the impact of HSPA equipments and devices evolution, from 3GPP R5 to R7 ones, on the capacity of a real macro-cell network. A simulation method has been developed. It combines drive test measurement...
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This paper studies the impact of HSPA equipments and devices evolution, from 3GPP R5 to R7 ones, on the capacity of a real macro-cell network. A simulation method has been developed. It combines drive test measurements, link-level simulations, and a statistical capacity model, which provides a reliable estimate of the network radio capacity. Different receiver schemes are simulated: linear receivers such as Rake/MMSE and a non-linear receiver using Successive Interference Cancellation (SIC). Simulation results show that the network capacity is higher with high HSDPA devices category. In particular, a significant capacity gain is achieved with MIMO combined with advanced receivers.
In this paper, we propose a generalized multiple-input multiple-output (MIMO) transmit preprocessing system, where both the channel coding and the linear MIMO transmit precoding components exploit the knowledge of the...
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In this paper, we propose a generalized multiple-input multiple-output (MIMO) transmit preprocessing system, where both the channel coding and the linear MIMO transmit precoding components exploit the knowledge of the channel. Moreover, we also propose a novel technique, hereby referred to as pilot symbol assisted rateless (PSAR) coding, where a predetermined fraction of binary pilot symbols is interspersed with the channel-coded bits at the channel coding stage, instead of multiplexing the pilots with the data symbols at the modulation stage, as in classic pilot symbol assisted modulation (PSAM). We will subsequently demonstrate that the PSAR code-aided transmit preprocessing scheme succeeds in gleaning more beneficial knowledge from the inserted pilots, because the pilot bits are not only useful for estimating the channel at the receiver, but they are also beneficial in terms of significantly reducing the computational complexity of the rateless channel decoder.
Steganography is a branch in the information hiding research area which aims to conceal data transmission between two parties. In this paper a new method based on predictive coding is proposed which employs Quantizati...
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Steganography is a branch in the information hiding research area which aims to conceal data transmission between two parties. In this paper a new method based on predictive coding is proposed which employs Quantization Index modulation (QIM) for quantizing error values and embedding data simultaneously. Furthermore, a correction mechanism is proposed to preserve the histogram of the cover image and make it resistant against histogram-based attacks. To evaluate the performance of the proposed method, several experiments on gray-level images are carried out and compared with two prominent methods called Jsteg and Steganography Based on Predictive coding (SBPC). The experimental results show that the proposed method achieves an efficient trade-off among imperceptibility, hiding capacity, compression ratio and robustness against malicious attacks.
Classical systems using hierarchical modulation (such as DVB-SH) involve a "high-priority" (HP) and a "low-priority" (LP) bit stream that are separately and independently encoded before being mappe...
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Classical systems using hierarchical modulation (such as DVB-SH) involve a "high-priority" (HP) and a "low-priority" (LP) bit stream that are separately and independently encoded before being mapped on non-uniformly spaced constellation points, leading to different levels of error protection. However, an inherent drawback of this scheme is the severe performance degradation of the less protected LP stream. In this paper, we propose a concatenated encoding scheme that mixes the two streams in order to make the encoding of the LP stream dependent on the well protected HP stream. Consequently, at the receiver side, the reliable information on HP bits provided by the HP decoder is naturally involved in the decoding process of the LP stream and acts as "soft pilots". We have exploited this feature inside a soft decoding mechanism in order to improve the LP decoding performance while keeping the HP decoding performance unchanged. Numerical results presented in the case of the DVB-SH standard show that the proposed system outperforms the classical approach in terms of LP bit error rate without a considerable increase in the receiver complexity.
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