Implementasi Dan Evaluasi Kinerja Encoder-Decoder Hamming Pada M-Ary Quadrature Amplitude Modulation (M-Qam) Mengunakan Wireless Open-Access Research Platform (Warp)

Salah satu kendala dalam sistem komunikasi digital adalah adanya bit error yang disebabkan oleh noise yang timbul selama proses transmisi berlangsung. Akibatnya data yang diterima pada penerima tidak sesuai dengan data yang dikirim. Apalagi jika modulasi yang digunakan adalah modulasi multilevel seperti M-ary Quadrature Amplitude Modulation (M-QAM). Semakin tinggi level modulasi maka tingkat kesalahannya pun semakin besar. Kode Hamming merupakan salah satu error control coding yang berfungsi untuk mendeteksi kesalahan (error detection) sekaligus memperbaiki kesalahan (error correction) bit. Kode Hamming mampu untuk mengoreksi kesalahan tunggal dalam satu blok. Pada Tugas Akhir ini, kode Hamming ( ), ( ), dan ( ) diimplementasikan pada M-QAM menggunakan modul Wireless Open-Access Research Platform (WARP) sebagai model pemancar dan penerima yang bersifat real-time. Hasil implementasi dan pengukuran pada sistem modulasi M-QAM dengan menggunakan kode Hamming menunjukkan bahwa Bit Error Rate (BER) menurun. Kode Hamming dapat bekerja dengan baik pada level modulasi 4-QAM, 8-QAM dan 16-QAM. Tingginya level modulasi menyebabkan peluang error semakin besar, sehingga pada level modulasi 32-QAM dan 64-QAM, kinerja kode Hamming kurang maksimal karena kemampuan koreksinya terbatas hanya satu bit error pada setiap bloknya. ============================================================================ One of the problems in digital communication systems is the presence of bit errors caused by noise that arises during the transmission process. As a result, the data received at the receiver is not in accordance with the data sent. Moreover, if the modulation used is multilevel modulation such as M-ary Quadrature Amplitude Modulation (M-QAM). Higher of modulation level is proportional with probability of errors. Hamming code is one of error control coding is used to detect errors (error detection) while fixing errors (error correction) bits. Hamming code is able to correct a single error in one block. In this final project, the Hamming code (7,4), (15,11) and (31,26) in the M-QAM are implemented using Wireless Open-Access Research Platform (WARP) modules as a transmitter and receiver models that are real- time. The implementation and results of measurements on M-QAM modulation system using Hamming code show that decreseas Bit Error Rate ( BER ). Hamming Code have good performance at the level modulation of 4-QAM, 8-QAM and 16-QAM. The high-level modulation causing higher probability of error, so the level modulation of 32-QAM and 64-QAM performance less than the maximum because the correction capability is limited to only a single bit error in each block

Error performance analysis of n-ary Alamouti scheme with signal space diversity.

Masters Degree. University of KwaZulu-Natal, Durban.In this dissertation, a high-rate Alamouti scheme with Signal Space Diversity is developed to improve both the spectral efficiency and overall error performance in wireless communication links. This scheme uses high modulation techniques (M-ary quadrature amplitude modulation (M-QAM) and N-ary phase shift keying modulation (N-PSK)). Hence, this dissertation presents the mathematical models, design methodology and theoretical analysis of this high-rate Alamouti scheme with Signal Space Diversity.To improve spectral efficiency in multiple-input multiple-output (MIMO) wireless communications an N-ary Alamouti M-ary quadrature amplitude modulation (M-QAM) scheme is proposed in this thesis. The proposed N-ary Alamouti M-QAM Scheme uses N-ary phase shift keying modulation (NPSK) and M-QAM. The proposed scheme is investigated in Rayleigh fading channels with additive white Gaussian noise (AWGN). Based on union bound a theoretical average bit error probability (ABEP) of the system is formulated. The simulation results validate the theoretical ABEP. Both theoretical results and simulation results show that the proposed scheme improves spectral efficiency by 0.5 bit/sec/Hz in 2 × 4 16-PSK Alamouti 16-QAM system compared to the conventional Alamouti scheme (16-QAM). To further improve the error performance of the proposed N-ary Alamouti M-QAM Scheme an × N-ary Alamouti coded M-QAM scheme with signal space diversity (SSD) is also proposed in this thesis. In this thesis, based on the nearest neighbour (NN) approach a theoretical closed-form expression of the ABEP is further derived in Rayleigh fading channels. Simulation results also validate the theoretical ABEP for N-ary Alamouti M-QAM scheme with SSD. Both theoretical and simulation results further show that the 2 × 4 4-PSK Alamouti 256-QAM scheme with SSD can achieve 0.8 dB gain compared to the 2 × 4 4-PSK Alamouti 256-QAM scheme without SSD

Multilevel Coded Modulation for Unequal Error Protection and Multistage Decoding—Part II: Asymmetric Constellations

In this paper, multilevel coded asymmetric modulation with multistage decoding and unequal error protection (UEP) is discussed. These results further emphasize the fact that unconventional signal set partitionings are more promising than traditional (Ungerboeck-type) partitionings, to achieve UEP capabilities with multilevel coding and multistage decoding. Three types of unconventional partitionings are analyzed for asymmetric 8-PSK and 16-QAM constellations over the additive white Gaussian noise channel to introduce design guidelines. Generalizations to other PSK and QAM type constellations follow the same lines. Upper bounds on the bit-error probability based on union bound arguments are first derived. In some cases, these bounds become loose due to the large overlappings of decision regions associated with asymmetric constellations and unconventional partitionings. To overcome this problem, simpler and tighter approximated bounds are derived. Based on these bounds, it is shown that additional refinements can be achieved in the construction of multilevel UEP codes, by introducing asymmetries in PSK and QAM signal constellations

Maximum Euclidean distance network coded modulation for asymmetric decode-and-forward two-way relaying

Network coding (NC) compresses two traffic flows with the aid of low-complexity algebraic operations, hence holds the potential of significantly improving both the efficiency of wireless two-way relaying, where each receiver is collocated with a transmitter and hence has prior knowledge of the message intended for the distant receiver. In this contribution, network coded modulation (NCM) is proposed for jointly performing NC and modulation. As in classic coded modulation, the Euclidean distance between the symbols is maximised, hence the symbol error probability is minimised. Specifically, the authors first propose set-partitioning-based NCM as an universal concept which can be combined with arbitrary constellations. Then the authors conceive practical phase-shift keying/quadrature amplitude modulation (PSK/QAM) NCM schemes, referred to as network coded PSK/QAM, based on modulo addition of the normalised phase/amplitude. To achieve a spatial diversity gain at a low complexity, a NC oriented maximum ratio combining scheme is proposed for combining the network coded signal and the original signal of the source. An adaptive NCM is also proposed to maximise the throughput while guaranteeing a target bit error probability (BEP). Both theoretical performance analysis and simulations demonstrate that the proposed NCM can achieve at least 3 dB signal-to-noise ratio gain and two times diversity gain

Simulation of WiMAX System Based on OFDM Model with Difference Adaptive Modulation Techniques

This paper presents the simulation of Worldwide Interoperability for Microwave Access (WiMAX) system based on Orthogonal Frequency Division Multiplexing (OFDM) with different adaptive modulation techniques. WiMAX is the next generation broadband wireless technology which offers greater range and bandwidth compared to the other available broadband wireless access technologies such as Wireless Fidelity (WiFi) and Ultra Wideband (UWB) family of standards. The simulation is based on the WiMAX physical layer which adopted an OFDM model in the transmitter and receiver. The Matlab software is used to develop the OFDM model and analysis the performance of WiMAX system. Hence the investigation of the performance of OFDM physical layer in WiMAX system by using different adaptive modulation techniques like Binary Phase Shift Keying (BPSK), Quadrature Phase Shift Keying (QPSK), Quadrature Amplitude Modulation (QAM) for modulator and demodulator. The performance of system was compared between the model with cyclic prefix and without cylic prefix. The cyclic prefix is added additional bits at the transmitter end. The signal is transmitted through the channel and it is received at the receiver end. Then the receiver removes these additional bits. The purpose of the cyclic prefix is to minimize the inter symbol interference and to improve the bit error rate. The analysis is based on the Bit Error Rate (BER), Signal to Noise Ratio (SNR) and probability error. At the end, the modulation BPSK and QPSK have the lower bit error rate while the 64 QAM has the higher bit error rate at low SNR. For the probability of error, the lower order modulation scheme also has the lower BER at low SNR

Design of cyclic prefix characteristic-based OFDM system for WiMAX technology

Worldwide interoperability for microwave access (WiMAX) offers the wireless connectivity using orthogonal frequency division multiplexing (OFDM) modulation is a proficient wireless technology that capacities high-speed data transmission facilities. The existing WiMAX techniques have the problem of increase in inter-symbol interference (ISI) and bit error rate (BER) at reduced power spectrum that degrades the performance of WiMAX system due to high data rate transmission. The utilization of different adaptive modulation techniques seen as a potential solution to reduce the ISI and BER for high data rate transmission. In this paper, OFDM is adapted using advanced modulation technique for WiMAX system. The technique proposes the cyclic prefix (CP) is utilized that include supplementary bits at the stage of the transmitter. The proposed technique offers minimization of ISI and improvement in BER. It is defined that performance of the existing CP system is equated with the designed single cyclic prefix (SCP) and double cyclic prefix (DCP) and non-cyclic prefix (NCP). BER, probability of error, and power spectral density are utilized to analyse the performance of the designed system. The OFDM based SCP and DCP and NCP for WiMAX are demonstrated for modulation techniques such as; QPSK, BPSK, and QAM. It is determined that BPSK has the smallest BER when compared to QPSK, 16-QAM, and 64-QAM modulations. It is also demonstrated that QPSK is also very competent, however, it has a higher BER as compared to BPSK modulation. It is also observed that 16-QAM and 64-QAM are less efficient in terms of BER compared to QPSK and BPKS modulations. 64-QAM offers the high data rates, and due to high SNR ratio. The designed system is tested for under AWGN and Rayleigh fading channel, and effect power spectral density of signal to noise ratio on OFDM for rayleigh fading channel are demonstrated for SCP and DCP and NCP. It is determined that the OFDM transmitter with proposed DCP for random signals is efficiently reducing the BER and ISI for WiMAX system

Generalized Spatial Modulation in Large-Scale Multiuser MIMO Systems

Generalized spatial modulation (GSM) uses $n_t$ transmit antenna elements but fewer transmit radio frequency (RF) chains, $n_{rf}$. Spatial modulation (SM) and spatial multiplexing are special cases of GSM with $n_{rf}=1$ and $n_{rf}=n_t$, respectively. In GSM, in addition to conveying information bits through $n_{rf}$ conventional modulation symbols (for example, QAM), the indices of the $n_{rf}$ active transmit antennas also convey information bits. In this paper, we investigate {\em GSM for large-scale multiuser MIMO communications on the uplink}. Our contributions in this paper include: ($i$) an average bit error probability (ABEP) analysis for maximum-likelihood detection in multiuser GSM-MIMO on the uplink, where we derive an upper bound on the ABEP, and ($ii$) low-complexity algorithms for GSM-MIMO signal detection and channel estimation at the base station receiver based on message passing. The analytical upper bounds on the ABEP are found to be tight at moderate to high signal-to-noise ratios (SNR). The proposed receiver algorithms are found to scale very well in complexity while achieving near-optimal performance in large dimensions. Simulation results show that, for the same spectral efficiency, multiuser GSM-MIMO can outperform multiuser SM-MIMO as well as conventional multiuser MIMO, by about 2 to 9 dB at a bit error rate of $10^{-3}$. Such SNR gains in GSM-MIMO compared to SM-MIMO and conventional MIMO can be attributed to the fact that, because of a larger number of spatial index bits, GSM-MIMO can use a lower-order QAM alphabet which is more power efficient.Comment: IEEE Trans. on Wireless Communications, accepte

Multiple trellis coded 16 QAM.

by Kingsley, King-chi, Kwan.Thesis (M.Phil.)--Chinese University of Hong Kong, 1994.Includes bibliographical references (leaves 85-88).Tables of ContentsLists of Figures & TablesAcknowledgmentsAbstractChapter Chapter 1 --- IntroductionChapter 1.1 --- Digital Communication System --- p.P. 1Chapter 1.2 --- Channel Coding --- p.P. 1Chapter 1.3 --- Convolution Encoder --- p.P. 4Chapter 1.4 --- Additive White Gaussian Noise (AWGN) Channel --- p.P. 7Chapter 1.5 --- Trellis Diagram --- p.P. 8Chapter 1.6 --- Error Event and Free Distance --- p.P. 8Chapter 1.7 --- Euclidean Distance --- p.P. 10Chapter 1.8 --- Organization of the Thesis --- p.P. 11Chapter Chapter 2 --- QAM and MTCMChapter 2.1 --- Introduction --- p.P. 13Chapter 2.2 --- M-ary Quadrature Amplitude Modulation (QAM)Chapter 2.2.1 --- M-ary Digital Modulation --- p.P. 13Chapter 2.2.2 --- Quadrature Amplitude Modulation (QAM) --- p.P. 14Chapter 2.2.3 --- Probability of Bit Error of M-ary QAM --- p.P. 16Chapter 2.3 --- Trellis Coded Modulation (TCM) --- p.P. 17Chapter 2.4 --- Multiple Trellis Coded Modulation (MTCM) --- p.P. 19Chapter Chapter 3 --- Set Partitioning of Signal SetsChapter 3.1 --- Introduction --- p.P. 21Chapter 3.2 --- Traditional Set Partitioning MethodsChapter 3.2.1 --- Ungerboeck's Set Partitioning Method --- p.P. 21Chapter 3.22 --- Set Partitioning by M.K. Simon and D. Divsalvar --- p.P. 23Chapter 3.3 --- The new Set Partitioning MethodChapter 3.3.1 --- Nomenclature of the Signal Points in the Signal Constellations --- p.P. 24Chapter 3.3.2 --- Generation of the Signal Sets --- p.P. 26Chapter 3.3.3 --- Partitioning of the Signal SetsChapter 3.3.3.1 --- Input Constraints of the Partitioning Method --- p.P. 30Chapter 3.3.3.2 --- The Set Partitioning Method --- p.P. 30Chapter 3.3.4 --- Distance Properties of the Partitioned Signal Sets --- p.P. 36Chapter 3.3.5 --- The Selection Scheme --- p.P. 39Chapter 3.3.6 --- Assignment of Signal Subsets into Trellis --- p.P. 42Chapter Chapter 4 --- Performance EvaluationChapter 4.1 --- Introduction --- p.P. 46Chapter 4.2 --- Upper Bound of Error ProbabilityChapter 4.2.1 --- Probability of Symbol Error --- p.P. 46Chapter 4.2.1.1 --- Upper Bound on Probability of Symbol Error --- p.P. 48Chapter 4.2.1.2 --- Computation of the Transfer Function --- p.P. 49Chapter 4.2.2 --- Probability of Bit Error --- p.P. 51Chapter 4.3 --- Computation of the Free Distance --- p.P. 53Chapter Chapter 5 --- Results Presentation and DiscussionsChapter 5.1 --- Introduction --- p.P. 58Chapter 5.2 --- Results PresentationsChapter 5.2.1 --- Normalized Square Free Euclidean Distance --- p.P. 58Chapter 5.2.2 --- Error Probability --- p.P. 71Chapter 5.3 --- Discussions --- p.P. 77Chapter Chapter 6 --- Conclusions --- p.P. 83Bibliography --- p.P. 85Chapter Appendix A - --- Flowchart of the Program --- p.P. 89Chapter Appendix B - --- Tabulated Results of d2free --- p.P. 10

On the use of the Gaussian approach for the performance evaluation of direct-detection OFDM receivers impaired by in-band crosstalk

The Gaussian approach (GA) is used to assess the impact of in-band crosstalk on the performance of direct-detection orthogonal frequency division multiplexing (OFDM) optical communication systems. The GA accuracy is compared with estimates of the bit error probability (BEP) and crosstalk penalty obtained using Monte Carlo (MC) simulation. The GA revealed a reduced accuracy when estimating the BEP. However, when estimating the 1 dB crosstalk penalty, the GA exhibited a good accuracy (less than 0.5 dB in comparison with the crosstalk level estimated using MC simulation), for 16-quadrature amplitude modulation (QAM) and 64-QAM mappings in the OFDM subcarriers. The GA leads to very discrepant estimates of the crosstalk penalty for high crosstalk levels.info:eu-repo/semantics/acceptedVersio