EXIT Chart Optimized Rate Matching for Wireless Communication Systems

Characterizing the energy cost of different physical (PHY) layer building blocks is becoming increasingly important in modern cellular-based communications, considering the cross sector requirements for performance enhancements and energy savings. This paper presents energy profiling metrics of different PHY-layer FPGA implementations encountered in modern wireless communication systems. The results give an insight of the distribution of the consumed energy in different baseband building blocks or configurations before and after applying power optimizations in the FPGA design and implementation.

In the modern wireless communication system, digital technology has tremendous growth, and all the communication channels are slowly moving towards digital form. Wireless communication has to provide the reliable and efficient transfer of information between transmitter and receiver over a wireless channel. The channel coding technique is the best practical approach to delivering reliable communication for the end-users. Many conventional encoder and decoder units are used as error detection and correction codes in the digital communication system to overcome the multiple transient errors. The proposed convolutional encoder consists of both Recursive Systematic Convolutional (RSC) Encoder and Adaptive Variable-Rate Convolutional (AVRC) encoder. Adaptive Variable-Rate Convolutional encoder improves the bit error rate performance and is more suitable for a power-constrained wireless system to transfer the data. Recursive Systematic Convolutional encoder also reduces the bit error rate and improves the throughput by employing the trellis termination strategy. Here, AVRC encoder ultimately acquires the channel state information and feeds the data into a fixed rate convolutional encoder and rate adaptor followed by a buffer device. A hybrid encoder combines the AVRC encoder and RSC encoder output serially and parallel, producing the solid encoded data for the modulator in the communication system. A modified turbo code is also obtained by placing interleaver between the two encoder units and building the stronger code word for the system. Finally, the conventional encoder system is compared and analyzed with the proposed method regarding the number of LUT’s, gates, clock cycle, slices, area, power, bit error rate, and throughput.

Solving channel equalization problem in communication systems is based on adaptive ltering algorithms. Today,Mobile Agents (MAs) with Recurrent Neural Networks (RNNs) can be also adopted for e ective interferencereduction in modern wireless communication systems (WCSs). In this paper MAs with RNNs are proposed asnovel computing algorithms for reducing interferences in WCSs performing an adaptive channel equalization.The method to provide it is so called MAs-RNNs. We perform the implementation of this new paradigm forinterferences reduction. Simulations results and evaluations demonstrates the e ectiveness of this approach andas better transmission performance in wireless communication network can be achieved by using the MAs-RNNsbased adaptive ltering algorithm.Keywords: Wireless communication systems, Mobile Agents, Recurrent Neural Networks, interferences reduc-tion, channel equalization 1. INTRODUCTION New challenges in modern communication is to conceive highly reliable and fast communication system deprivedfrom problems caused by multipath fading in wireless channels. A very important problem in data commu-nications is channel equalization. i.e., the removal of interferences introduced by linear or nonlinear messagecorrupting mechanisms. Thus the originally transmitted symbols can be recovered correctly at the receiver.New techniques to provide the optimal detection under bad channel estimation and solving the channel equal-ization must be developed and evaluated. To achieve fast and reliable wireless digital communication, as forinter-symbol interference (ISI), studies must concern adaptive equalization to minimize the communication errors

In modern wireless communication systems, accurate characterization of wireless propagation channels remains a significant challenge. In multiple-input multiple-output (MIMO) wireless systems, a double-directional channel can be achieved by utilizing multipath components' spatial and temporal properties (MPCs). Grouping the MPC can simplify the parameters as a trade-off between complexity and accuracy. This paper implements k-Deep Auto Encoder (k-DAE), AE+k-means, and K Power Means (KPM) clustering approaches and compares their performance in clustering wireless propagation multipaths in indoor and outdoor scenarios. The results show that AE+k-means performs better than k-DAE in indoor scenarios by 25.48%, while k-DAE performs 24.60 % better in outdoor scenarios. The KPM algorithm performs best in all indoor scenarios among the three algorithms, with a significant increase of 4.38% and 11.062% to AE+k-means and k-DAE, respectively. However, both k-DAE and AE+k-means have quite similar performance in outdoor scenarios. The study also highlights the first use of autoencoders in clustering the MPCs. The results indicate that k-DAE can be used as an alternative clustering method in channel modeling. Future works envisioned applying the approach to other wireless channel models.

Energy efficiency is always an essential concern in modern wireless communication systems. Energy harvesting is a promising technique and can substantially extend the lifetime of power-critical wireless systems such as wireless sensors. Unlike the traditional battery powered system, the system utilizing energy harvesting usually has a smaller battery or merely a super-capacitor. Rather than the limitation on the maximum energy capacity, it is much more critical to take considerations on the energy harvesting rate when an optimal transmission strategy is proposed for such wireless communication systems. In this paper, we study the above issues, and develop an innovative framework considering the characteristics of the wireless communication systems with energy harvesting. The balance between the available resources such as harvested energy and the output such as successful packets is optimized. The simulation results show that our proposed framework works better in all scenarios compared with the baseline strategy.

Now a days, the demand for wireless communication systems with high data rates and high capacity has dramatically increased. CDMA (Code Division Multiple access) plays an important role in modern wireless communication systems. MIMO refers to links with multiple antennas at the transmitter and receiver side. CDMA with MIMO is a very promising technique beyond 3G and 4G wireless communications. The BER performance of MIMO-CDMA system depends on its spreading strategy. In this paper MIMO-CDMA system is designed with STBC (Space-Time Block Code) matrices for spreading. The proposed technique outperforms the tdesign permutation spreading method and also the conventional method. Simulation results shows that gain improvement with STBC approach as compared to other existing techniques.

Adaptive techniques play a key role in modern wireless communication systems. The concept of adaptation is emphasized in the Adaptation in Wireless Communications Series through a unified framework across all layers of the wireless protocol stack ranging from the physical layer to the application layer, and from cellular systems to next-generation wireless networks. Adaptation and Cross Layer Design in Wireless Networks is devoted to adaptation in the data link layer, network layer, and application layer. The book presents state-of-the-art adaptation techniques and methodologies, including cross-layer adaptation, joint signal processing, coding and networking, selfishness in mobile ad hoc networks, cooperative and opportunistic protocols, adaptation techniques for multimedia support, self organizing routing, and tunable security services. It presents several new theoretical paradigms and analytical findings which are supported with various simulation and experimental results. Adaptation in wireless communications is needed in order to achieve high capacity and ubiquitous communications. The current trend in wireless communication systems is to make adaptation dependent upon the state of the relevant parameters in all layers of the system. Focusing on simplified cross layer design approaches, this volume describes advanced techniques such as adaptive resource management, adaptive modulation and coding, 4G communications, QoS, diversity combining, and energy and mobility aware MAC protocols. The first volume in the series, Adaptive Signal Processing in Wireless Communications (cat no.46012) covers adaptive signal processing at the physical layer.

The advancement of mobile communications has rapidly expanded in recent years, with the invention of transmitting and receiving system technology. The use of multiple antennas, also known as Multiple-Input Multiple-Output (MIMO) technology, is a key feature in modern wireless communication systems such as 5G. MIMO utilizes multiple antennas at both the transmitter and receiver to improve the system's performance in terms of data rate, link reliability, and spectral efficiency. In this paper, a block coding technique, was deployed to enhance the reliability of data transmission and introducing redundancy and error correction capabilities. These techniques involve encoding data into blocks and adding redundancy bits, which allow the receiver to detect and correct errors that may occur during transmission. The encoding technique, called the Asymmetric Arithmetic Coder (AAC), and it is supported in 5G system to provide high speed signal transmission in multiple users’ environment. For retrieving a smooth signal at the receiver, a filter was introduced to improve its efficiency of the wireless link. However, the existing filter in the system, caused the increasing of the peak-to-average-power-ratio (PAPR) at the transmitter system. Thus, the block coding technique was implemented to increase the efficiency and reduced the power ratio. The most common block coding technique for wireless communication is AAC technique. The AAC technique was founded to reduce the power ratio and further improve the signal diversity. Recently, for the application of 5G, the AAC was enhanced by adding the number of symbol and improved the PAPR. It is called the Enhancement Asymmetric Arithmetic Coding (EAAC) technique. The EAAC contributes to the lower value of the PAPR. With the use of EAAC as the block coding technique, the transmitter is said to support the system and thus improved the PAPR measurements by 5.5%. Lastly, the reduction of PAPR contributes to minimize the distortion and enhanced spectral efficiency for wireless communication system.

Multiple-input multiple-output (MIMO) system is a very promising technique in modern wireless communication systems, which can meet the demand of high data rate with limited bandwidth. Integration of MIMO technology with mobile ad hoc network can improve the performance of transmission process in hazardous environment. In order to design a real MIMO wireless system and predict its performance under certain circumstances, it is necessary to have accurate MIMO wireless channel models for different scenarios. Mobile ad hoc network with multiple antennas suffers scattering effects. A combination of two ring model and random scattering model is described in this paper to evaluate channel impulse response of the network. Channel impulse response or channel matrix is used to estimate the propagation loss of the MIMO-based mobile ad hoc network in different terrain. Finally, a minimum loss secure path selection is described here using path loss-based administrator selection secure routing protocol (PASR) protocol to select loss less secure route for transmission.

In modern wireless communication systems, a combination of multiple-input multiple-output (MIMO) system with the orthogonal frequency division multiplexing (OFDM) technique can be used to achieve high data rate and & better spectral efficiency. A Channel estimation technique using pilot carriers for multiple input multiple output (MIMO) systems for a Rayleigh fading channel is proposed in this paper. The channel estimation is carried out with conventional Least Square (LS) and Minimum Mean Square (MMSE) estimation algorithms. The performance of MIMO-OFDM system is evaluated on the basis of Bit Error Rate (BER) and Mean Square Error (MSE) level.

In this contribution, a Si-LDMOS transistor is used to design a power amplifier (PA) in a broad frequency band covering a number of modern wireless communications systems. The design, implementation, and experimental results of 4 W wideband Si-LDMOS PA are presented. A method based on source/load--pull characterization has been used to extract optimum source and load impedances over the desired bandwidth. Following this, a systematic approach to design wideband matching network is suggested. In the frequency band 1.7-2.7 GHz, 3.4 - 4.0 W output power and 25 % drain efficiency were achieved. The 3rd-order intermodulation distortion (IMD3) performance of the designed PA is evaluated by providing a two-tone signal to the amplifier. At two-tone output power of 1 W, IMD3 of around -30 dBc was measured over the design band.

This research article discusses the design methodology and related findings of a compact triband printed bandpass filter (TBP-BPF). The geometry of the proposed model is based on two open-loop rectangular resonators coupled with two open stubs. The prototype of the proposed TBP-BPF is fabricated on a compact surface area of (10.7 × 7.25) mm2 and measured with a vector network analyzer (VNA) to validate the simulation outcomes. The proposed filter exhibits low insertion losses of 0.51, 0.7, and 0.36 dB at the respective operating bands. Furthermore, the designed BPF model maintains a return loss |S 11| of ≥ 10 dB at all operating bands centered at 2.48, 3.22, and 5.87 GHz, respectively. The proposed BPF shows multiple passbands with excellent insertion and return loss characteristics by maintaining an attractive compact size. It can be used efficiently in various modern data communication systems such as WLAN, Bluetooth, Wi-Fi, and WiMAX.

In this study, a novel periodic leaky‐wave antenna (LWA) with wide beam‐scanning angle and low cross‐polarisation is proposed by using miniaturised composite right/left‐handed transmission line (CRLH TL). By introducing the metallic holes loaded in the interdigital lines of the miniaturised CRLH TL, not only the parasitic resonant modes can be eliminated, but also the miniaturisation is realised. Considering the continuous phase constants from negative to positive values of the balanced CRLH TL, a continuous beam‐scanning property from backward to forward of the resultant LWA can be obtained. For verification, a periodic LWA, which consists of 20 unit cells of the balanced CRLH TL, is fabricated and measured; the measured and simulated results are in good agreements with each other, indicating that the fabricated LWA operates from 3.90 to 4.90 GHz (a bandwidth of 22.7%), and has a wide continuous beam‐scanning capability from backward −61° to forward 67° (including the broadside) within the operating band. Moreover, it also has very low cross‐polarisation, which remains at a level of at least 25 dB below the co‐polarisation across the entire radiation region. As a result, the presented LWA should find promising applications in modern wireless communication systems and the high‐resolution radar system due to these wonderful electromagnetic performances.

Power amplifier plays a great important role in modern wireless communication system. In this paper, a class-AB power amplifier working in 2.11GHz–2.17GHz is designed and fabricated, tuned, measured. The measurement results show that the output power at 1dB compression point (P1dB) is 46.5dBm along with a drain efficiency of 36.9% at central frequency 2.14GHz. The upper TOI measured using a two-tone signal is 52.98 dBm, and the lower TOI 53.04 dBm. The results of simulation and measurement are compared and analyzed.

Hybrid automatic retransmission request (HARQ) in modern wireless communication systems such as 4G and 5G is designed to allowing efficient combining of multiple (re)transmissions so as to to achieve coding gain. The coding performance for each retransmission in isolation may, however, not be consistent, potentially lacking self-decodability of individual retransmissions. This can require the UE to receive multiple additional retransmissions when the initial transmission is missed, undermining the intended efficiency of the HARQ system. In this paper, we discuss the self-decodability of HARQ retransmissions and show it can be improved, providing a balance between coding gain and self-decodability, by modifying the rate-matching operation without changing the channel code construction. We present results illustrating the gains in self-decodability using the proposed scheme.