Broadband Multimedia Services Research Articles

Resource Allocation for Millimeter-Wave Train-Ground Communications in High-Speed Railway Scenarios

With the development of wireless communication, higher requirements arise for train-ground wireless communications in high-speed railway (HSR) scenarios. The millimeter-wave (mm-wave) frequency band with rich spectrum resources can provide users in HSR scenarios with high performance broadband multimedia services, while the full-duplex (FD) technology has become mature. In this paper,we study train-ground communication system performance in HSR scenarios with mobile relays (MRs) mounted on rooftop of train and operating in the FD mode. We formulate a nonlinear programming problem to maximize network capacity by allocation of spectrum resources. Then, we develop a sequential quadratic programming (SQP) algorithm based on the Lagrange function to solve the bandwidth allocation optimization problem fortrack-side base station (BS) and MRs in this mm-wave train-ground communication system. Extensive simulation results demonstrate that the proposed SQP algorithm can effectively achieve high network capacity for train-ground communication in HSR scenarios while being robust to the residual self-interference (SI).

The Quality of Video Communication in Encrypted Traffic

Abstract The rapid development of network and computer technologies creates opportunities for offering advanced broadband multimedia services to a growing number of end users. Instant messaging and group communication services based on real-time video transmission based on global Internet resources are the most popular. The basic challenge related to the implementation of video transmission services is to ensure an appropriate level of quality and security (Quality & Security). The article presents a multi-criteria assessment of the impact of encryption protocols for multimedia video transmissions on the perceived quality of QoE (Quality of Experience) service implementation. The presented measurement method together with the proposed research methodology create the possibility of determining the likelihood of video service availability with accepted QoE in heterogeneous networks.

Efficient Transmission of an Encrypted Image Through a MIMO–OFDM System with Different Encryption Schemes

In today’s world, broadband multimedia services are growing at a rapid pace. It is very much essential to secure data in financial, defense, health care, government, and marketing services. To ensure the data from eavesdroppers, the physical layer security (channel coding, modulation schemes, and diversity techniques, etc.) is one of the best solutions. The security attributes at this level reduce maintenance, operational cost, and complexity without affecting the quality of service. Physical layer security with cryptographic techniques makes it well suited for transferring multimedia data through unsecure or potentially risky communication (wired and wireless) path. To provide security attributes to an image/data, one needs to protect the transmitted data from unauthorized access. Several encryption algorithms have been proposed to ensure confidentiality and security for multimedia data over an insecure wireless channel. Cryptography techniques do not involve any system complexity but add a little computation complexity. Use of advanced processors mitigates the computational burden. In this paper, efficient transmission of an encrypted image through a multiple-input multiple-output orthogonal frequency division multiplexing (MIMO–OFDM) system over an additive white Gaussian noise channel with different encryption schemes is presented. The advanced encryption standard (AES), data encryption standard (DES), and Rubik’s Cube encryption algorithms are incorporated to improve security aspects. The comparison aims to select the most appropriate wireless communication systems (2 × 2 MIMO–OFDM and 4 × 4 MIMO–OFDM), and the most suitable image encryption algorithm for efficient transmission of the encrypted image. The quality of the received image is evaluated using the peak signal-to-noise ratio between the original and decrypted image at different signal-to-noise (SNR) ratio. Performance estimates of the cryptosystems are also provided by computing the bit-error-rate at different SNR. The Performance estimates of encryption algorithms (irrespective of the MIMO–OFDM system) are also included, which consists of various performance metrics. The metrics are histogram, entropy, correlation coefficient, number of changing pixel rate, and unified averaged changed intensity. From the MATLAB simulation experiments, it is observed that the performance of 4 × 4 Crypto-MIMO–OFDM system configurations outperformed 2 × 2 Crypto-MIMO–OFDM system configurations. The performance of the Crypto-MIMO–OFDM system is compared with the original MIMO–OFDM system performance without encryption algorithm. For all variants of Crypto-MIMO–OFDM systems, the use of Rubik’s Cube encryption algorithm shows significant improvement over DES and AES.

Energy Efficient Scheduling in Content Distribution Collaborative Mobile Clusters

Most of the existing literatures on green communications aimed to improve the energy efficiency at the base station or data server. However, in order to fully experience high rate broadband multimedia services, prolonging the battery life of user equipment is also critical for the mobile terminals, especially for the smartphone users. In this work, we investigate the problem of designing a content distribution mobile platform named collaborative mobile clusters (CMC) via user cooperation to reduce the energy consumption at the terminal side. Specifically, given numbers of users interested in downloading a common content from the operator, both centralized and distributed user grouping and scheduling algorithms are proposed in order to find the proper user to join the CMC in different scheduling time with the objective to obtain energy efficiency as well as user fairness. Through simulation studies, it is shown that a significant energy saving can be achieved by the proposed schemes and user fairness can be maintained as well.

Energy Efficient Power Allocation for Delay Constrained Cognitive Satellite Terrestrial Networks Under Interference Constraints

With the ever increasing spectrum demand of broadband multimedia services, cognitive satellite terrestrial networks have emerged as a promising paradigm for future space information networks. To provide services with diverse delay quality-of-service (QoS) requirements in an energy-limited system, in this paper, we investigate energy efficient power allocation for cognitive satellite terrestrial networks. Employing statistical delay-QoS metric, power allocation schemes are formulated as optimization problems to maximize effective energy efficiency of secondary satellite communications while satisfying interference constraints imposed by primary terrestrial communications. Specifically, allowing for the availability of instantaneous channel state information (CSI) of the secondary transmitter-primary receiver link, optimal transmit powers are derived for both the cases of statistical and instantaneous interference constraints. Moreover, to provide a theoretical insight on the performance of the considered network, we derive closed-form expressions for the outage probability based on the obtained optimal transmit powers. The simulation results demonstrate the validity of the theoretical results and show the impacts of the delay exponent, interference constraint, and aggregate interference from terrestrial networks on the performance of satellite networks.

Stochastic Optimization for Green Multimedia Services in Dense 5G Networks

The manyfold capacity magnification promised by dense 5G networks will make possible the provisioning of broadband multimedia services, including virtual reality, augmented reality, and mobile immersive video, to name a few. These new applications will coexist with classic ones and contribute to the exponential growth of multimedia services in mobile networks. At the same time, the different requirements of past and old services pose new challenges to the effective usage of 5G resources. In response to these challenges, a novel Stochastic Optimization framework for Green Multimedia Services named SOGMS is proposed herein that targets the maximization of system throughput and the minimization of energy consumption in data delivery. In particular, Lyapunov optimization is leveraged to face this optimization objective, which is formulated and decomposed into three tractable subproblems. For each subproblem, a distinct algorithm is conceived, namely quality of experience--based admission control, cooperative resource allocation, and multimedia services scheduling. Finally, extensive simulations are carried out to evaluate the proposed method against state-of-art solutions in dense 5G networks.

Disparities in the Induced Rain Attenuation between Beacon (Narrowband) and Broadband Satellite Links in Tropical Zones

<span lang="EN-GB">The utilisation of higher frequency bands above 10 GHz by the satellite industries to provide the bandwidth (BW) required for broadband multimedia services, video conferencing, direct-to-home TV programmes and IP data requires the understanding of atmospheric losses and good link planning for satellite-to-earth links. The trade-off between the service availability, data rate and BW determine the type of modulation scheme and error corrections to be employed. These services also depend on the link performance under adverse atmospheric conditions, especially rain-induced attenuation. In this research, study measurements were conducted on space-to-earth satellite links using the beacon narrowband and broadband IP carrier signals of a Nigcomsat-1R satellite operating at 42.5°E. A VSAT receiving terminal at a latitude of 7.4°N, longitude of 9.04°E and altitude of 334 m above sea level was utilised to quantify the rain-induced attenuation of both the beacon and broadband signals during rain events. The measurements were then compared with the link performance under clear sky conditions. The performance revealed that, when compared with the broadband signal, the induced rain attenuation on beacon signal presented a disparity in the responses, resulting in significant variations of 10.14 dB in the carrier-to-noise ratio (C/N) and 17.42 dB in the received signal level at a Ku-band frequency of 12.518 GHz. These observations were also compared with the Crane global rain map and ITU-R P.618-12. Both models disagreed with the measurement values for Abuja, Nigeria.</span>

Integrated Network Management for ATM and Broadband Networks using Integrated Speed Bit Protocol

High speed network covers several means of communication and the innovation accomplished in networks had a significant impact on communication concerning terminals and computers. Obviously asynchronous transfer mode (ATM) has appeared as the most significant technology in supporting imminent broadband multimedia communication services, considered to decrease the complexity of the network and advancement in the flexibility of traffic performance and a conventional technique incorporate network management for ATM network is stochastic estimator learning algorithm. Although introduced numerous methods, high speed is the fundamental issue in networking and as it is the asynchronous mode, the sending process continuous to send the data cells that prompts the temporary memory overflow at the receiver side. In this paper propose a new protocol integrated speed bit protocol (ISBP) for integrated network management to preserve the objects. Initially the ISB protocol preserves speed bit manager which encloses the prioritized objects and the objects having the data about the systems, the objects priority vanquished through specific priority factors. As a result the transaction process done faster and the synchronization have the capacity to finish in asynchronous mode, so the temporary memory losses get avoided and consumed more time. Thus the proposed integrated network management for ATM and Broadband networks using ISB protocol system has embraced with the assistance of the speed bit protocol and the experimental results demonstrated that the performance of the system enhanced significantly.

Energy Efficient Resource Allocation for Wireless Power Transfer Enabled Collaborative Mobile Clouds

In order to fully enjoy high rate broadband multimedia services, prolonging the battery lifetime of user equipment is critical for mobile users, especially for smartphone users. In this paper, the problem of distributing cellular data via a wireless power transfer enabled collaborative mobile cloud (WeCMC) in an energy efficient manner is investigated. WeCMC is formed by a group of users who have both functionalities of information decoding and energy harvesting, and are interested for cooperating in downloading content from the operators. Through device-to-device communications, the users inside WeCMC are able to cooperate during the downloading procedure and offload data from the base station to other WeCMC members. When considering multi-input multi-output wireless channel and wireless power transfer, an efficient algorithm is presented to optimally schedule the data offloading and radio resources in order to maximize energy efficiency as well as fairness among mobile users. Specifically, the proposed framework takes energy minimization and quality of service requirement into consideration. Performance evaluations demonstrate that a significant energy saving gain can be achieved by the proposed schemes.

Two-Phase Multicast DRX Scheduling for 3GPP LTE-Advanced Networks

For next-generation wireless communications, the 3GPP Long Term Evolution-Advanced (LTE-A) is the most promising technology which provides transmission rate up to 1 Gbps and supports various broadband multimedia services, such as IPTV and Voice/Video-over-IP services. To reduce the energy consumption of user equipments (UEs) , the LTE-A standard defines the Discontinuous Reception Mechanism (DRX) to allow UEs to turn off their radio interfaces and go to sleep when no data needs to be received. However, how to optimally configure DRX for UEs is still left as an open issue. In this paper, we address the DRX optimization problem for multicast services. This problem asks how to guarantee the quality of service (QoS) of the multicast streams under the Evolved Node B (eNB) while minimizing the UEs’ wake-up time. We prove this problem to be NP-complete and propose an energy-efficient heuristic. This heuristic consists of two phases. The first phase tries to aggregate the required bandwidth of the multicast streams for UEs to reduce their wake-up periods. The second phase further minimizes UEs’ unnecessary wake-up periods by optimizing their DRX configurations. Extensive simulation results show that our scheduling is close to the optimum in most cases.

Cross‐polarisation discrimination‐induced interference in dual‐polarised high‐capacity satellite communication systems

The design of spectrally-efficient, high-throughput satellite (HTS) systems with capacity approaching one terabit per second requires operating at Ka-band frequencies and above, where there are several gigahertz of allocated radio spectrum, using multiple spot beams with dual orthogonal polarisation mode. At these high frequencies, rain attenuation poses a major obstacle to the design of high-availability satellite links which are needed for the realisation of ubiquitous broadband multimedia communication services including high-speed Internet access at rural and remote locations. Furthermore, depolarisation-induced interference in such systems could have a performance-limiting impact if a co-channel cross-polar signal combines with system noise to drive the carrier-to-noise-plus-interference ratio (CNIR) below an acceptable threshold. This paper employs real measurement data to investigate the impact of depolarisation-induced interference on dual-polarised HTS systems for temperate and tropical climatic regions. Scenarios that cause significant system performance degradation are analysed, including the effects of signal frequency, antenna size, and regional rainfall rate. The impact of depolarisation on system performance is quantified by the reductions in the CNIR and link availability of a dual-polarised system when compared with those of a similarly-dimensioned single-polarised system.

Delay analysis of MSW-ARQ system based on wireless multimedia services

This paper firstly analyzes the transmission mechanism of the wireless broadband multi-media services in the MSW-ARQ(Multi-channel Stop-and-Wait ARQ) system. Considering the real-time multimedia service's four features (high requirement for delay but allows some loss rate, the constraints of the delay and jitter), in order to meet with professional standard, we model the real-time multimedia service packet transmission as an M[X]/G/1 queuing model for MSW-ARQ. The packet transition probability is derived by constructing steady state Markov Chain based on the method of selecting the reference packet. On the basis of equivalent service delay, we also solve the packet mean service delay. Then under the given condition, we analyze the influence of the channel number and channel environments on the mean delay through numerical simulating. The characteristics and superiorities of multi-channel transmission mechanism in wireless communication are checked enough by solving the M[X]/G/1 queuing model. So this paper provides useful thought and approach for optimizing system delay and throughput by checking the change of channel environments and the used number of parallel channels.

Smart Downlink Scheduling for Multimedia Streaming Over LTE Networks With Hard Handoff

This paper presents a novel smart downlink scheduling scheme to enhance the performance of multimedia transmission over long-term evolution (LTE) networks. LTE represents a promising framework for the next-generation broadband multimedia services because of its significantly increased data rate over 3G cellular networks. However, the current LTE scheduling scheme has largely been designed for general data traffic without adequate consideration of multimedia characteristics. Moreover, the hard handoff (HO) procedure adopted in LTE will further degrade the multimedia services when the mobile user moves from one cell to another. Even with increased data rate, current LTE systems still cannot deliver the expected quality of service (QoS) to the mobile users under various mobility scenarios, especially when the hard HO is evoked. Aiming at overcoming these major challenges, we develop in this paper a QoS-driven smart downlink scheduling scheme for enhanced multimedia transmission over LTE networks. The proposed design shall take the following QoS metrics into consideration: 1) the delay constraint of voice-over-Internet protocol flow; 2) the packet deadline of video flow; and 3) the service degradation induced by the hard HO procedure. We achieve the design objectives by creating three QoS-driven operational control modules: 1) a transmission delay control module to ensure the on-time arrival of various types of multimedia data; 2) an HO control module to warrant continuous multimedia services when the user moves across a cell boundary; and 3) a resource allocation module to strategically map the requested flows to best fit radio resource blocks. The simulation results confirm the performance gain of the proposed scheme.

Demonstration and field trial of a resilient hybrid NG-PON test-bed

A multi-layer next generation PON prototype has been built and tested, to show the feasibility of extended hybrid DWDM/TDM-XGPON FTTH networks with resilient optically-integrated ring-trees architecture, supporting broadband multimedia services. It constitutes a transparent common platform for the coexistence of multiple operators sharing the optical infrastructure of the central metro ring, passively combining the access and the metropolitan network sections. It features 32 wavelength connections at 10Gbps, up to 1000 users distributed in 16 independent resilient sub-PONs over 100km. This paper summarizes the network operation, demonstration and field trial results.

Performance Analysis of Resilient FTTH Architecture with Protection Mechanism

Fiber-To-The-Home [FTTH] is an alternate technology for broadband access networks. Passive optical network (PON) is considered the most promising solution due to the relatively low deployment cost. Current time division multiplexing [TDM] PON architectures are economically feasible, are band limited. The WDM PONs currently available offers enough bandwidth for the present and also for future multimedia broadband services. The purpose of this paper is to simulate resilient access network architecture with a cable route protection function based on hybrid wavelength division multiplexing and time division multiplexing passive optical network (WDM/TDM-PON) systems. Hybrid WDM-TDM PON combines the advanced features of both TDM PON and WDM PON. The reuse of existing optical fiber cable networks allows the introduction of duplicate routes for the shared portions of PONs by using a few optical fiber cables with simple structures. In this work, the hybrid WDM/TDM PON based Ladder network is simulated and the transmission characteristics evaluated. Simulation is done by using Optsim ver.5.3.

Performance Analysis of Resilient FTTH Architecture with Protection Mechanism

Fiber-To-The-Home [FTTH] is an alternate technology for broadband access networks. Passive optical network (PON) is considered the most promising solution due to the relatively low deployment cost. Current time division multiplexing [TDM] PON architectures are economically feasible, are band limited. The WDM PONs currently available offers enough bandwidth for the present and also for future multimedia broadband services. The purpose of this paper is to simulate resilient access network architecture with a cable route protection function based on hybrid wavelength division multiplexing and time division multiplexing passive optical network (WDM/TDM-PON) systems. Hybrid WDM-TDM PON combines the advanced features of both TDM PON and WDM PON. The reuse of existing optical fiber cable networks allows the introduction of duplicate routes for the shared portions of PONs by using a few optical fiber cables with simple structures. In this work, the hybrid WDM/TDM PON based Ladder network is simulated and the transmission characteristics evaluated. Simulation is done by using Optsim ver.5.3.

Reliable cooperative multicasting for MBS WiMAX traffic

Cooperative multicast communication techniques for emerging broadband multimedia services over WiMAX reduces network resource consumption, by broadcasting the data simultaneously to multiple users independently of their number, on a common shared downlink channel. Users distributed around the cell face different channel conditions due to fading, user location, mobility, and other related issues. Recently, several schemes were reported in the literature that attempt to introduce cooperative multicasting reliably and efficiently, some of which utilize subscribers with good-channel as Relay Agents (RAs) to provide coverage for subscribers suffering bad-channel conditions but ignore the large amount of energy consumed in the process. In this paper, we propose energy-efficient cooperative multicasting schemes by properly selecting RAs based on their location, channel condition and coverage. By exploiting the channel state information (CSI) and the location based service (LBS), three protocols based on nearest neighbor, transmission distance and subscriber-subscriber interlink instantaneous CSI were proposed and implemented in order to improve the system’s energy consumption performance. Number of RAs was varied according to channel conditions on a frame-per-frame basis. This approach considerably reduces the amount of energy consumed as proven by analysis and simulation models, providing a lower cost coverage solution with no dereliction in achieved throughput.

Statistical Analysis of Field Strength Location Variability for UHF Multimedia Broadband Services

This letter investigates the location variability of the field strength for dimensioning broadcast networks targeting mobile reception. A statistical analysis of empirical data from three European cities is performed for services in UHF band, specifically in TV bands IV and V (470-860 MHz). This work demonstrates that currently used values based on ITU-R P.1546-1 are too pessimistic and lead to inefficient network dimensioning.

Digital Dividend: The Path Towards Business and Marketing Development

Information and Communication Technologies (ICT) enable a large number of users worldwide to receive advanced real time services provided by sophisticated networking platforms. More specifically, access to mobile broadband networks, in the case where wire-line access is restricted, enables users to ubiquitously communicate at anytime. From the European Union’s (EU) perspective, the Lisbon Treaty envisions providing significant improvements in mobile broadband multimedia services and Internet access for European citizens. For this purpose, the European Commission puts effort to create a pan-European network of mobile services through the harmonization of spectrum use by all EU Member States in the future. Furthermore, television radio spectrum, which is a range of low frequencies in VHF and UHF bands, is traditionally used exclusively by analogue television broadcasters. This part of the radio spectrum offers attractive features, such as high penetration of buildings, wide coverage and moreover, the wavelength of the UHF band signals is short enough such that resonant antennas with small footprint can be used, enabling the provision of signals to many portable and handheld devices. However, regulatory rules do not allow unlicensed devices in the television bands, except of the remote control devices, medical telemetry devices and wireless microphones (PMSE).

CIR Samples and Channel Taps Based WindowedDFT Channel Estimation for MIMOOFDM System

For high capacity demand for 4G broadband multimedia and internet services with high quality of service (QoS), multiple input multiple output (MIMO) transmission methods are exploited for high speed machine to machine communication. In order to mitigate the fast fading multipath effects, orthogonal frequency division multiplexing (OFDM) is used as modulation technique for MIMO systems. Time-domain channel characteristics are used to make efficient channel state information (CSI) available at the transmitter side. In this paper Windowed-DFT technique is optimized for channel estimation and the performance and complexity are determined. Computer Simulations are used to show the effect of channel filter length and the number of multipath channel taps.