Variable Content Characteristic and Variable Network Coding for Wireless Digital Video Broadcasting Application

Long Term Evolution (LTE) network offers a high throughput with low latency that makes it the best choice for Evolved Multimedia Broadcast Multicast Service (E-MBMS). E-MBMS transmits data to all users simultaneously using the same channel and same Modulation and Coding Scheme (MCS) level. Each user experiences different channel condition, so an MCS level should be selected properly to satisfy all users. Typically, MCS level is selected on the basis of users' worst channel condition which results in wasting network resources. Since the E-MBMS performance directly depends on the selected MCS level, an efficient Adaptive Modulation and Coding (AMC) scheme is essentially needed. This paper introduces a new mechanism that uses the Standard Deviation (SD) of MCS level of E-MBMS user group operated on single cell mode to efficiently select its optimal MCS level. Simulation results show that the proposed mechanism increase the spectrum efficiency, throughput, and lower Packet Loss Ratio compared to the Worst User Channel Condition mechanism and Fixed Predefined MCS mechanism.

Recently, the importance of channel coding has become prominent for next-generation 5G wireless communication networks. Channel coding is becoming an active area of research and scholars are aiming to improve their knowledge about channel coding schemes which will be playing a crucial part in high-performance 5G networks. polar codes are the class of channel coding techniques that have been standardized in 5G. Moreover, it is a fact that activity tool-based learning raises the learning efficiency and generates intrinsic motivation for learning. Therefore, the main motivation for designing this paper is to develop a Graphical User Interface (GUI) based learning tool to help students easily learn channel coding techniques. In our teaching curriculum, we have used figure-based interactive representations to teach the basic concepts of polar codes efficiently. This learning tool provides users the option to learn about the encoding technique and two different decoding techniques named as Successive Cancellation (SC) and Successive Cancellation List (SCL) for different lengths of user-defined data bits. This complete model has been designed in Python.

Third generation mobile communication systems like the European UMTS will enable a flexible communication, free from standard specific regulation of modulation, channel coding, baud rate and multiple access schemes. This flexibility can only be reached by a radio structure which performs all baseband functions in software and is therefore totally software programmable. To ensure that different software configurations can be understood and supported by all mobile terminal architectures a general programming language is required to describe the used air interface components. By the example of the second generation mobile communication systems like the European GSM, the Japanese PDC, the American IS-54 (respectively IS-136) and the European wireless communications system DECT, a common description and implementation of the transceiver functions like channel coding, modulation and equalisation have been developed.

The established success of wireless communications in terms of high data rates provision is undoubtedly owed to several combinations of different mechanisms. Such a combination is the well-known forward error correction (FEC) mechanism that combines automatic-repeat-request (ARQ) protocol and error correction capabilities. Furthermore, in the last decade, a cross-layer design provides the combination of different mechanisms across the layers and thus the performance gain is increased in wireless communications over fading channels. In this paper, we present a practical cross-layer design implementation that combines adaptive modulation and coding (AMC) and hybrid ARQ at the physical and data link layer by using different error correction schemes. Our implementation is based on a cross-layer design of AMC and HARQ. We perform simulations with different channel coding and modulation schemes that are implemented in broadband wireless access networks as IEEE 802.16 and 3GPP HSPA and thus the results obtained show the performance achieved by this practical cross-layer implementation in terms of spectral efficiency in two main broadband wireless access networks available into the market.

Channel coding is a fundamental procedure in wireless telecommunication systems and has a strong impact on the data transmission quality. This effect becomes more important when the transmission must be characterised by low latency and low bit error rate, as in the case of vehicle-to-everything (V2X) services. Thus, V2X services must use powerful and efficient coding schemes. In this paper, we thoroughly examine the performance of the most important channel coding schemes in V2X services. More specifically, the impact of use of 4th-Generation Long-Term Evolution (4G-LTE) turbo codes, 5th-Generation New Radio (5G-NR) polar codes and low-density parity-check codes (LDPC) in V2X communication systems is researched. For this purpose, we employ stochastic propagation models that simulate the cases of line of sight (LOS), non-line of sight (NLOS) and line of sight with vehicle blockage (NLOSv) communication. Different communication scenarios are investigated in urban and highway environments using the 3rd-Generation Partnership Project (3GPP) parameters for the stochastic models. Based on these propagation models, we investigate the performance of the communication channels in terms of bit error rate (BER) and frame error rate (FER) performance for different levels of signal to noise ratio (SNR) for all the aforementioned coding schemes and three small V2X-compatible data frames. Our analysis shows that turbo-based coding schemes have superior BER and FER performance than 5G coding schemes for the vast majority of the considered simulation scenarios. This fact, combined with the low-complexity requirements of turbo schemes for small data frames, makes them more suitable for small-frame 5G V2X services.

A new integrated framework for source and channel rate allocation is presented for video coding and transmission over wireless channels without feedback channels available. For a fixed total channel bit rate and a finite number of channel coding rates, the proposed scheme can obtain the near-optimal source and channel coding pair, and corresponding robust video coding scheme such that the expected end-to-end distortion of video signals can be minimized. With the assumption that the encoder has the stochastic information such as average SNR and Doppler frequency of the wireless channel, the proposed scheme takes into account robust video coding, channel coding, packetization, and error concealment techniques altogether. An improved method is proposed to recursively estimate the end-to-end distortion of video coding for transmission over error-prone channels. The proposed estimation is about 1-3 dB more accurate compared to the existing integer-pel based method. Rate-distortion optimized video coding is employed for the trade-off between coding efficiency and robustness to transmission errors.

To support truly peer-to-peer applications in ad hoc wireless networks, a judicious and efficient ad hoc routing protocol is needed. Much research has been done on designing ad hoc routing protocols and some well known protocols are also being implemented in practical situations. However, one major drawback in existing state-of-the-art protocols, such as the AODV (ad hoc on demand distance vector) routing protocol, is that the time-varying nature of the wireless channels among the mobile terminals is ignored, let alone exploited. In this paper, by using a previously proposed adaptive channel coding and modulation scheme which allows a mobile terminal to dynamically adjust the data throughput via changing the amount of error protection incorporated, we devise a new ad hoc routing algorithm that dynamically changes the routes according to the channel conditions. Extensive simulation results indicate that our proposed protocol is more efficient in that shorter delays and higher rates are achieved.

This paper provides a technical review of the Chinese Digital Terrestrial Television Broadcasting Standard (DTTB), which defines the physical layer transmission protocol, including the frame structure, channel coding, and modulation schemes. Key technologies adopted into this standard, such as time-domain synchronous orthogonal frequency division multiplexing (TDS-OFDM), etc., are discussed in detail. Measurement results from independent third parties show satisfactory receiving performance of high-definition and standard-definition TV signals under both indoor and outdoor environments for fixed and mobile reception. Major differences between this Chinese standard and the Digital Video Broadcasting-Terrestrial (DVB-T) standard, which has the largest deployment worldwide and also occupies an 8-MHz analog bandwidth, are also briefly addressed.

We propose a new nonlinear Rao-Nam like symmetric key encryption scheme. In our design, we employ a specific type of coded modulation schemes namely quasi-cyclic low-density parity-check (QC-LDPC) lattice-codes which have low-complexity encoding and decoding algorithms. Due to the application of coded modulation schemes in our design, the proposed scheme performs encryption, encoding and modulation simultaneously. Therefore, we regard the proposed scheme as a joint cryptosystem. The proposed joint cryptosystem withstands all variants of chosen plaintext attacks applied on Rao-Nam like cryptosystems due to its nonlinearity. Moreover, some conditions implying the uniformity of the ciphertexts distribution are introduced through our analysis. Our scheme is efficient and admits small key size. These features are obtained due to several reasons including the quasi-cyclic form of the generator and the parity-check matrices of QC-LDPC lattice-codes, and the simple hardware structure for generating the permutation matrix, the intentional error vector and the nonlinear functions used in our design. The QC-LDPC lattice-codes facilitate high-rate transmission which is suitable for bandlimited AWGN channels. Our simulations indicate that QC-LDPC lattice-codes outperform the error performance of high-order coded modulation schemes based on QAM modulations. Hence, our scheme provides secure, reliable and efficient data transmission in bandlimited AWGN channels.

In this paper, we consider a wireless multicast network with multiple sources, relays, and destinations. We adopt a multi-hop decode-and-forward relay protocol such that two canonical subnetworks are relevant, namely broadcast channel with receiver side information (BC-RSI) and orthogonal multiple access channel with correlated sources and receiver side information (MAC-CS-RSI). A joint network and channel coding (JNCC) strategy is proposed by exploiting ARQ, RSI, and correlated sources. The proposed JNCC strategy does not require the knowledge of RSI nor any transmit channel state information, such that each transmitter simply performs retransmissions until the intended receivers have accumulated enough mutual information to successfully decode all desired messages. This successful decoding is then conveyed from the receivers to the respective transmitters via an acknowledgement message. To measure the performance of the proposed JNCC strategy with ARQ, we derive closed-form expressions of network throughput by applying the renewal-reward theorem. Analytical results show that the proposed JNCC strategy outperforms, in terms of network throughput, the conventional separate network and channel coding strategy with random linear network coding.

This paper compares the forward link radio link capacity between variable spreading factor-orthogonal frequency and code division multiplexing (VSF-OFCDM) with one-cell frequency reuse and orthogonal frequency division multiplexing (OFDM) with conventional three-cell frequency reuse or with one-cell frequency reuse utilizing symbol repetition, considering the effect of sectorization and the adaptive modulation and channel coding (AMC) scheme in a multi-cell environment in a broadband multipath fading channel. Simulation results demonstrate that, although the achievable radio link capacity in VSF-OFCDM is approximately 1.5 fold greater compared to that in OFDM with three-cell frequency reuse, almost identical radio link capacity under full channel-load conditions is realized in VSF-OFCDM and OFDM with one-cell frequency reuse applying elaborate symbol repetition transmission to suppress other-cell interference. Meanwhile, to achieve a lower data rate channel than the peak rate, higher-quality transmission is possible in VSF-OFCDM employing two-dimensional spreading compared to OFDM, by utilizing the frequency diversity effect in frequency domain spreading. Consequently, we conclude that VSF-OFCDM is superior to OFDM in broadband wireless access, since the former provides higher-quality transmission and more flexible accommodation of the lower data rate channels, along with the flexibility in designing essential channels such as the control and pilot channels.

Highly efficient and robust source coding, channel coding, and packetization techniques are proposed for video streaming over wireless ATM. At the base station, which is located at the boundary of the wireline and wireless networks, video received from the wireline source is dynamically transformed to match both the hardware capabilities of mobile hosts and the time-varying wireless channel conditions. For wireless transmission, source coding, channel coding, and packetization are jointly implemented as part of the application. For source coding, we propose to use our three-dimensional significance-linked connected component analysis video codec. For channel coding and packetization, both intracell and interlaced (intercell) forward error correction are applied. Furthermore, the time-varying channel characteristics is exploited by adaptively allocating the total bit budget between source coding and channel coding. Extensive performance evaluation demonstrates the effectiveness of the proposed wireless video streaming technique.

Multimedia encoders typically generate symbols having a wide range of legitimate values. In practical mobile wireless scenarios, the transmission of these symbols is required to be bandwidth efficient and error resilient, motivating both source coding and channel coding. However, separate source and channel coding (SSCC) schemes are typically unable to exploit the residual redundancy in the source symbols, which cannot be totally reduced by finite-delay finite-complexity schemes, hence resulting in a capacity loss. Until recently, none of the existing joint source and channel codes (JSCCs) were suitable for this application since their decoding complexity rapidly increases with the size of the symbol alphabet. Motivated by this, we proposed a novel JSCC referred to as the unary error correction (UEC) code, which is capable of exploiting all residual redundancy and eliminating any capacity loss, while imposing only a moderate decoding complexity. In this paper, we show that the operation of the UEC decoder can be dynamically adapted to strike an attractive tradeoff between its decoding complexity and its error correction capability. Furthermore, we conceive the corresponding 3-D EXtrinsic Information Transfer (EXIT) charts for controlling this dynamic adaptation, as well as the decoder activation order, when the UEC code is serially concatenated with a turbo code. In this way, we expedite iterative decoding convergence, facilitating a gain of up to 1.2 dB compared with both SSCC and to its nonadaptive UEC benchmarkers, while maintaining the same transmission bandwidth, duration, energy, and decoding complexity.

In this paper, we present a multiple hierarchical coding and transmission scheme in which both the fragile structure of set partitioning in hierarchical trees (SPIHT) source coding and the unequal importance of bits in the coded bitstream have been taken into account. Multiple subsampling is applied to split the wavelet coeffcients of the original image source into multiple subsources so that each subsource is a crude representation of the original image. The sequential dependence of coded bitstream is broken. As a result, the error propagation is limited to a single subsource which is also coded with SPIHT to achieve desired coding performance. Cyclic redundancy coder/rate compatible punctured convolutional coder (CRC/RCPC) channel coding has been used to offer unequal error protection (UEP) to the multiple coded bitstreams. In each substream all the bits in the same bit layer are protected with the same channel code. The higher the bit-layer, the more the channel coding protects. Experimented results show that this new scheme has a good error resilient performance over wireless channels with time varying and bursty errors characteristics. In particular the reconstructed images often demonstrate good visual quality.

Transmission efficiency, defined as the ratio of successfully transmitted information bits to overall bits transmitted, can be used for evaluating the transmission performance of wireless links. As a function of received signal to noise ratio (SNR), transmission efficiency is determined by physical layer technologies, such as channel coding, interleaving, modulation and other error-recovery techniques of wireless links. In this paper we first analyze the form of transmission efficiency function in wireless links, then based on that we propose an adaptive coding scheme that maximizes the transmission efficiency according to wireless channel conditions (received SNR). Simulation results show that with the proposed adaptive coding, transmission efficiency of wireless links can be significantly enhanced.