Multimedia Broadcast Multicast Service Research Articles

Optimal Resource Allocation for Loss-Tolerant Multicast Video Streaming.

In video streaming applications, especially during live streaming events, video traffic can account for a significant portion of the network traffic and can lead to severe network congestion. For such applications, multicast provides an efficient means to deliver the same content to a large number of users simultaneously. However, in multicast, if the base station transmits content at rates higher than what can be decoded by users with the worst channels, these users will experience outages. This makes the multicast system's performance dependent on the weakest users in the system. Interestingly, video streams can tolerate some packet loss without a significant degradation in the quality experienced by the users. This property can be leveraged to improve the multicast system's performance by reducing the dependence of the multicast transmissions on the weakest users. In this work, we design a loss-tolerant video multicasting system that allows for some controlled packet loss while satisfying the quality requirements of the users. In particular, we solve the resource allocation problem in a multimedia broadcast multicast services (MBMS) system by transforming it into the problem of stabilizing a virtual queuing system. We propose two loss-optimal policies and demonstrate their effectiveness using numerical examples with realistic traffic patterns from real video streams. It is shown that the proposed policies are able to keep the loss encountered by every user below its tolerable loss. The proposed policies are also able to achieve a significantly lower peak SNR degradation than the existing schemes.

A Multi-Antenna Pilot Predistortion Scheme and Channel Estimation Algorithm for LTE-Based Terrestrial Broadcast System

Multi-Antenna technology is a physical layer technique widely used in mobile communication and terrestrial broadcast systems. For fully utilizing the antenna diversity, conventional Multi-Antenna pilots usually meet the characteristic of orthogonality in terms of the pilot arrangement to avoid inter-pilot interference between different transmitting antennas. However, the scheme with orthogonality leads to the doubling of the pilot overhead, which seriously reduces the transmission efficiency. The latest LTE-based terrestrial broadcast system, Further evolved Multimedia Broadcast Multicast Service (FeMBMS), is probably to adopt the Multi-Antenna technique in the future, but no corresponding pilot scheme has been provided. This paper proposes a novel pilot pre-distortion scheme and Channel Estimation (CHE) algorithm for FeMBMS. The pre-distortion scheme does not require the pilot on different antennas to meet the restriction of orthogonality, so to address the problem of pilot overhead doubling. Meanwhile, it deals with the issue of inter-pilot interference by converting the interference into the white noise spreading over the whole OFDM symbol. Furthermore, the proposed CHE algorithm effectively eliminates the whitened interference by utilizing the processing of DFT-based windowing and Iterative Interference Cancellation (IIC). Simulation shows that the pre-distortion scheme and CHE algorithm could provide a CHE performance with accuracy same or close to that of the orthogonality scheme while significantly improving the transmission efficiency.

Machine Learning-Based 5G RAN Slicing for Broadcasting Services

Along with the commercialization of evolved multimedia broadcast multicast services (eMBMS), the number of mobile broadcasting users is growing notably. Previous works reveal that the accuracy of mobile channel estimation will significantly impact the quality of broadcasting services. Motivated by this fact, we apply machine learning (ML) to the fifth-generation Radio Access Network (5G RAN) slicing in this paper for the estimation and the prediction of the channel status in mobile scenarios. More specifically, a cascaded convolutional neural network (CNN)-long short term memory network (LSTM) architecture is developed to achieve channel estimation for mobile broadcasting users. The energy efficiency of the base station (BS) is modeled mathematically, and the sub-optimal solution is achieved by deep Q-Network (DQN) based on the available channel status. Finally, we present the simulation results to justify the performance of our proposed schemes.

Experimental Assessment of New Generation Radio Networks Based on Layered Division Multiplexing

Despite the recent advances in broadband penetration and accessibility, broadcasting networks continue to be the most efficient way for delivering media content to large areas independently of the user density. Nevertheless, a convergence of broadcasting services into the broadband networks is foreseen. In this context, Layered Division Multiplexing (LDM) allows the joint provision of unicast, multicast, and broadcast services in mobile cells infrastructure. Despite the success of LDM in broadcasting infrastructure, its practical application in Long Term Evolution networks providing Evolved Multimedia Broadcast Multicast Services (LTE eMBMS) and 5G-MBMS is more difficult. In this paper, we experimentally quantify the cell-interference and its impact on the network performance and Quality of Service. Our experiments reveal that the inter-cell interference margin for LTE eMBMS is about 3 dB higher compared to traditional LTE networks. If a layered architecture is incorporated this higher inter-cell interference would cause a reduction of approximately 19% of the Enhanced Layer (Lower Layer) coverage.

Aliasing-Elimination Channel Estimation for CAS Reception

Multimedia Broadcast Multicast Service (MBMS)-dedicated cell is a Long Term Evolution (LTE) based broadcast transmission mode with both high transmission efficiency and good compatibility with LTE unicast systems. However, since the physical design of Cell Acquisition Subframe (CAS), which is the control part of an MBMS-dedicated cell transmission period, does not take into account the long delay spread channels in Medium Tower Medium Power (MTMP) and High Tower High Power (HTHP) cells, receivers would probably suffer from multipath aliasing errors in practical transmission. This paper analyzes the impact of aliasing errors on channel estimation (CHE) accuracy and proposes an Aliasing-Elimination CHE algorithm for CAS reception. In the proposed algorithm, the pre-decoded Physical Broadcast Channel (PBCH) is reconstructed and utilized to generate a complete multipath distribution within the entire OFDM symbol length. By using this full-symbol length multipath distribution, the proposed algorithm eliminates aliasing errors effectively. Simulation results and complexity analysis show that the proposed CHE algorithm achieves a significant performance improvement compared to conventional CHE algorithms in long delay spread channels, with acceptable increment in complexity.

An improving performance cellular DTV broadcasting with hybrid non-orthogonal LDM and orthogonal eMBMS configuration

In this article, we focus on the hybrid of orthogonal and non-orthogonal broadcasting. The hybrid configuration is raised and proposed for improving cellular digital television broadcasting (CDTB) technology. The hybrid scheme is configured as layered division multiplexing (LDM) multiplexed with an evolved multimedia broadcast multicast service (eMBMS) standalone layer is superimposed. The LDM and eMBMS are sub-sections of power division-non orthogonal multiple access (PD-NOMA) and long-term evolution (LTE) respectively. We assume perfect knowledge of the channel state information (CSI) over the Rayleigh fading multipath channel. The bit error rate (BER) and outage probability performance criteria are investigated. The impact of injection level using the fractional transmit power allocation (FTPA) algorithm is discussed. The proposed hybrid can operate in conditions without a subscriber identity module (SIM) card for uplink beamforming and internet protocol (IP). The broadcast network provider selection is feasible by the user equipment (UE) device. Performance analysis is derived based on the exact closed-form expressions, which allows the theory of hybrid proposed LDM/eMBMS consistent with results. Evaluations and performance will be done based on the Monte Carlo iterative methodology. The results show that the performance and efficiency will be increased when a proposed hybrid LDM/eMBMS configuration is compared with LDM and eMBMS services individually.

The MBSFN-based eMBMS using the method of Incremental Allocation of Radio Resource between Unicast and Multicast (IARR-UM)

The evolved Multimedia Broadcast Multicast Service (eMBMS) using the Multicast Broadcast Single Frequency Network (MBSFN) technique was designed for having multimedia streaming services using the multicast/broadcast way over the cellular network. Since (1) the unit of resource allocation in eMBMS-MBSFN is a subframe, (2) the code rate of an eMBMS-MBSFN session is based on the lowest Modulation and Coding Scheme (MCS) among involved User Equipments (UEs) of the eMBMS-MBSFN session and (3) the resource allocation for eMBMS-MBSFN cannot be so instantly and dynamically adjusted based on the status of involved UEs, triggering eMBMS-MBSFN in the inappropriate time and allocating inappropriate resource to eMBMS, for which a framework of how to set the configuration of the allocated resource for eMBMS-MBSFN has been defined in the standard, may cause (1) the radio resources to be wasted and (2) the low streaming quality and code rate. Based on the MBMS operation on Demand (MooD) concept, this work proposed the Incremental Allocation of Radio Resource between Unicast and Multicast (IARR-UM) method to dynamically allocate radio resources to eMBMS based on the current Radio Access Network’s (RAN’s) congestion situation such that some suitable multimedia streaming services are switched to eMBMS and others still use unicast communication. To effectively use eMBMS to mitigate RAN’s congestion, the proposed IARR-UM method (1) dynamically increases/decreases the amount of radio resources allocated to eMBMS, i.e., modifying the configuration of the allocated resource for eMBMS-MBSFN using the standard’s framework, based on the situation of RAN’s congestion, (2) uses the Knapsack algorithm to select a subset of suitable multimedia streaming services to be eMBMS sessions according to the given amount of radio resources allocated to eMBMS, and then (3) design a Common Subframe Allocation (CSA) pattern that can have the lower amount of redundant radio resources allocated to eMBMS. The results of the performance evaluation shown that the proposed method can (1) provide UEs with appropriate radio resources and (2), although the throughput may be reduced in some cases, effectively reduce (increase) the UEs’ invalid packet rates (data rates), especially in the higher density of UEs’ situation.

MBSFN or SC-PTM: How to Efficiently Multicast/Broadcast

In Multimedia Broadcast/Multicast Service(MBMS), Multicast/Broadcast Single Frequency Network (MBSFN) and Single-cell Point-to-multipoint Network (SC-PTM) are two essential ways to organize networks to provide multicast services. MBSFN shows its unique advantage of enhancing signals at the boundary of two cells, however, highly requiring synchronization of symbols. SC-PTM shows the advantage of the flexibility on the network deployment. The comparison and complementarity of these two modes are explored. In this paper, we analyze the reception performance of MBSFN and SC-PTM from multiple perspectives. We first compare the successful transmission probability (STP) of MBSFN with that of SC-PTM. Then, we consider optimal power control problems in MBSFN and SC-PTM. The corresponding power control optimization problems are with fraction and max-min forms and solved by the Dinkelbach algorithm. Furthermore, we propose a joint mode-selection and power-control method in the hybrid mode of MBSFN and SC-PTM, where each cell could select the multicast mode from MBSFN and SC-PTM. This is a mixed-integer nonlinear programming (MINLP) problem and solved by the concave-convex procedure (CCCP) and the Dinkelbach algorithm. To further improve the throughput, the appropriate successful reception proportion is selected under the opportunistic multicast. Finally, the numerical simulations show the performance of our algorithms and compare the throughput of two modes, which verify our analysis.

Optimizing Video QoE for Mobile eMBMS Users in Cellular Networks

Evolved Multimedia Broadcast Multicast Service (eMBMS) is used in cellular networks to improve the utilization of scarce wireless resources in high user density service areas. However, eMBMS configuration involves interwoven decisions including which base stations (eNB) to synchronize to form Single Frequency Networks (SFN), which video qualities to be serviced, and how to distribute resources among different videos. These decisions should accommodate disparate channel conditions for eMBMS users, and the impact of eNB's unicast-load in the service area. In this paper, we formulate eMBMS configuration as an optimization problem that maximizes the video QoE for users. Additionally, we present NIMBLE as an eMBMS configuration heuristic, guided by our optimization framework, to solve the problem in realtime. Furthermore, NIMBLE's design integrates elements to accommodate the dynamic nature of cellular networks resulting from changes in both user, and network state over time. We developed a simulation testbed, and performed extensive experiments to show that, in comparison to state-of-the-art schemes, NIMBLE can increase the average user throughput by 150%, and reduce the bitrate switches by 75%.

Challenges and Solutions for Cellular Based V2X Communications

A wide variety of works have been conducted in vehicle-to-everything (V2X) communications to enable a variety of applications for road safety, traffic efficiency and passenger infotainment. Although dedicated short-range communications (DSRC) based V2X is already in the deployment phase, cellular based V2X is gaining more interest in academia and industry most recently. This article surveys the existing work and challenges on LTE and 5G to support efficient V2X communications. First, we present the motivations for cellular based V2X communications. Second, we summarize the LTE V2X architecture and operating scenarios being considered. Third, we discuss the challenges in existing LTE for supporting V2X communications such as physical layer structure, synchronization, multimedia broadcast multicast services (MBMS), resource allocation, security and survey the recent solutions to these challenges. We further discuss the challenges and possible solutions for 5G based vehicular communications. Finally, we discuss the open research issues and possible research directions in cellular based vehicular communications.

Improved Delay Priority Resource Scheduling with Low Packet Loss Rate for MBMS in LTE Systems

An improved delay priority resource scheduling algorithm with low packet loss rate for multimedia broadcast multicast service (MBMS) in long term evolution (LTE) systems is proposed in this paper. Real-time services in LTE systems require lower delay and packet loss rate. However, it is difficult to meet the QoS requirements of real-time services using the current MBMS resource scheduling algorithm. The proposed algorithm in this paper jointly considers user delay information and real-time channel conditions. By introducing the user delay information, the lower delay and fairness of users are guaranteed. Meanwhile, by considering the channel conditions of users, the packet loss rate can be effectively reduced, improving the system throughput. Simulation results show that under the premise of ensuring the delay requirements of real-time services, the proposed algorithm achieves a lower packet loss rate compared to other existing algorithms. Furthermore, it can achieve a good balance between system throughput and user fairness.

UMUcast: A Framework for Massive Small-Data Delivering in Industrial Internet of Things

As a key infrastructure of Industry 4.0, Industrial Internet-of-Things (IIoT) promises the opportunity to build powerful industrial environments by leveraging the growing ubiquity of wired and wireless communication technologies. Designing a data delivery scheme in the future IIoT networks is undoubtedly a challenging task, as it should satisfy several conflicting requirements: massive-scale, data-intensive, and mission-critical, the requirements of which have motivated the desired need for feasible IIoT network architecture. In particular, the traffic characteristics of certain IIoT applications feature small-data patterns especially in typical automation control scenarios such as robot control on the downlink. In order to reduce the huge overhead associated with each individual unicast transmission of the small-data message, we propose a novel “multipoint-to-multipoint” and/or “point-to-multipoint with different contents” communication paradigm-Uni-Multi-Unicast (UMUcast), which is based-on traditional 4G technologies such as evolved Multimedia Broadcast Multicast Service (eMBMS) and Group Communication System Enablers (GCSE), and novel 5G technologies such as Multi-Access Edge Computing (MEC). For the downlink, the UMUcast transmitter can jointly encode multiple-sources' small-data messages into a single chunk at MEC equipment in conjoint with a gNB, where chunk can be one-off transmission to multiple receivers simultaneously through an eMBMS frame, whereas the chunk is decoded into multiple small-data by each individual IIoT devices separately and respectively. The simulation results show that UMUcast has remarkable improvements over conventional point-to-point unicasting in handling multi-source, multi-destination, and massive small-data delivery with characteristics of low-overhead, high-throughput, and ultra-low-latency for future 5G-based IIoT networks.

A Dynamic Clustering Algorithm for Multi-Point Transmissions in Mission-Critical Communications

Reliable group video call is one of the main services offered by future Mission-Critical Communications (MCC). To support its requirements, coordinated multi-point transmission in multi-cell environments is an attractive feature for MCC over Multimedia Broadcast Multicast Services owing to its potential for coverage improvement and multicast transmission. In such a scheme, full cooperation among all cells of an area achieves the highest cooperative gain, but has stringent impact on system capacity. A trade-off in the cluster’s size of serving cells thus arises between high Signal to Interference plus Noise Ratio (SINR) and network capacity. In this paper, we formulate an optimization problem to maintain an acceptable system blocking probability, while maximizing the average SINR of the multicast group users. For every multicast group to be served, a dynamic cluster of cells is selected based on the minimization of a submodular function that takes into account the traffic in every cell through some weights and the average SINR achieved by the group users. Traffic weights are then optimized using a modified Nelder-Mead simplex method with the objective of tracking a blocking probability threshold. The proposed clustering scheme is compared to full cooperation and to Single-Cell Point-To-Multipoint (SC-PTM) schemes. Results show that dynamic clustering offers the best trade-off between coverage and capacity for MCC.

Multimedia Public Warning Alert Trials Using eMBMS Broadcast, Dynamic Spectrum Allocation and Connection Bonding

The European Commission requires all European Union (EU) Member States to use telecommunications networks to alert the population of an ongoing crisis or an upcoming threat by June 2022. Public Warning System in Long Term Evolution (LTE) and 5G System currently supports a text-based warning using Cell Broadcast technology. Cell Broadcast does not support multimedia warning message delivery. This paper analyses requirements that need to be fulfilled to support multimedia warning message delivery in the 5G System and describes trials of a broadcast multimedia public warning alert system. The trials demonstrate delivery of multimedia public warning messages using Evolved Multimedia Broadcast Multicast Service (eMBMS), dynamic spectrum management and bonded connections. By using eMBMS the public warning messages can be sent with additional robustness and in multicast mode, resulting also in less congestion to the network as the messages do not need to be sent separately to each user. Dynamic spectrum management system allows to dynamically obtain spectrum resources for the public warning system messages and the bonded connections improves the throughput and reliability of the delivery by combining the capacity of several different networks.

Cellular Terrestrial Broadcast—Physical Layer Evolution From 3GPP Release 9 to Release 16

We present the latest developments in the physical layer evolution for the transmission of Multimedia Broadcast Multicast Service (MBMS) over fifth generation (5G) cellular networks. We first provide an overview of how the MBMS physical layer has evolved during the initial releases of the Third Generation Partnership Project (3GPP) specifications and provide motivations and insights for key developments that have helped mature MBMS into a competitive broadcasting solution. We provide an overview of dedicated MBMS carriers for Multimedia Broadcast multicast service Single Frequency Network (MBSFN) transmission as well as Orthogonal Frequency Division Multiplexing (OFDM) numerologies with longer cyclic prefixes to support MBSFN transmission over large geographical areas with large distances between cooperating cell sites. Next, we describe the most recent enhancements to the MBMS physical layer, addressing advanced use cases in the recently completed release of the 3GPP specifications (Release 16). First, we describe the physical layer design for enabling MBSFN-based MBMS services for rooftop receivers with inter-site distances between cooperating cell sites as large as 125 km. In this realm, we demonstrate the need for an OFDM numerology with a 300-microsecond cyclic prefix to communicate effectively over channels with very large delay spreads. Next, we explain how support for high mobility up to 250 kmph was added to the standards by using an OFDM numerology that gracefully trades off inter-symbol interference due to large delay spreads and inter-carrier interference due to large doppler spreads to achieve better performance than existing numerologies at high speeds. Finally, we describe the enhancements that were made to the Cell Acquisition Subframe (CAS)—specifically, the introduction of larger aggregation levels for the Physical Downlink Control Channel (PDCCH) and the support of Physical Broadcast Channel (PBCH) repetitions—that significantly increase the coverage for the control and system information associated with MBMS that are carried by these subframes.

Service-Less Video Multicast in 5G: Enablers and Challenges

The massive upsurge in production and demand of crowdsourced live streaming necessitates feasible and cost effective solutions in future cellular networks. Video multicast is one of the viable options to deliver live video using standardized multicast technologies, such as evolved Multimedia Broadcast Multicast Services (eMBMS) architecture. However, eMBMS being a service-oriented architecture, it does not support crowdsourced live video streaming from popular providers like Twitch, YouTube Live, and Facebook Live, where millions of viewers watch live streams. This article explores the possibilities for the crowdsourced service-less video multicast in fifth generation (5G) Radio Access Network (RAN). We highlight major limitations in the standard eMBMS architecture and propose a viable solution using Network Function Virtualization (NFV) and Mobile Edge Computing (MEC). The main challenges related to the initiation of an eMBMS service are presented, followed by our proposed network architecture, which augments the eMBMS architecture to initiate a service-less multicast video delivery for crowdsourced live videos. We evaluate and validate the proposed architecture using a real-world live video dataset. Our results depict the feasibility of the proposed architecture to multicast crowdsourced live streams and significant savings in cost and network consumption.

Using Non-Orthogonal Multiplexing in 5G-MBMS to Achieve Broadband-Broadcast Convergence With High Spectral Efficiency

The development of 5G system provides a unique opportunity to implement a unified wireless transmission platform that can simultaneous deliver unicast, multicast and broadcast services using the same spectrum and the same infrastructure. This can be achieved by developing a more capable point-to-multipoint transmission (PTM) system component, also called 5G Multimedia Broadcast Multicast Services (5G-MBMS). A properly designed 5G-MBMS could achieve the convergence of terrestrial mobile broadband and TV broadcasting systems.By inherently allowing dynamic spectrum allocation among different types of services, this converged system could offer significant higher spectrum utilization. In this paper, the power-based non-orthogonal multiplexing (P-NOM) technology is proposed in addition to the existing orthogonal time-division-multiplexing (TDM) scheme. Significant capacity gains could be achieved by using P-NOM in a 5G-MBMS system for delivering different types of broadcast services, and for delivering mixed unicast and broadcast services. The capacity benefits of a 5G-MBMS with P-NOM is demonstrated by both theoretical analysis and computer simulations. A key finding is that using a two-layer P-NOM can essentially deliver a broadcast service on top of a unicast network, each achieving nearly full capacity. Next, a complexity analysis will reveal that implementing P-NOM in a 5G-MBMS system does not require significant additional complexity at consumer devices. Finally, it will be shown that, different from the non-orthogonal-multiple-access (NOMA) technologies, using P-NOM in 5G-MBMS system requires little or no change to the existing radio resource allocation mechanisms in LTE and 5G, when one power layer is used for broadcast services delivery.

5G Radio Access Network Architecture for Terrestrial Broadcast Services

The 3rd Generation Partnership Project (3GPP) has defined based on the Long Term Evolution (LTE) enhanced Multicast Broadcast Multimedia Service (eMBMS) a set of new features to support the distribution of Terrestrial Broadcast services in Release 14. On the other hand, a new 5th Generation (5G) system architecture and radio access technology, 5G New Radio (NR), are being standardised from Release 15 onwards, which so far have only focused on unicast connectivity. This may change in Release 17 given a new Work Item set to specify basic Radio Access Network (RAN) functionalities for the provision of multicast/broadcast communications for NR. This work initially excludes some of the functionalities originally supported for Terrestrial Broadcast services under LTE e.g. free to air, receive-only mode, large-area single frequency networks, etc. This paper proposes an enhanced Next Generation RAN architecture based on 3GPP Release 15 with a series of architectural and functional enhancements, to support an efficient, flexible and dynamic selection between unicast and multicast/broadcast transmission modes and also the delivery of Terrestrial Broadcast services. The paper elaborates on the Cloud-RAN based architecture and proposes new concepts such as the RAN Broadcast/Multicast Areas that allows a more flexible deployment in comparison to eMBMS. High-level assessment methodologies including complexity analysis and inspection are used to evaluate the feasibility of the proposed architecture design and compare it with the 3GPP architectural requirements.

An Effective and Efficient Dynamic eMBMS Multicast Grouping Scheduling Algorithm in MBSFNs for Public Safety Scenarios.

The LTE (Long-Term Evolution) eMBMS (evolved Multimedia Broadcast Multicast Service) technology employed in MBSFNs (Multicast Broadcast Single Frequency Networks) has been shown to be capable of considerably increasing the capacity of serving public safety users under group communication scenarios. However, due to its own limitations, a more fine-tuned scheduling approach is needed in order to fully utilize the strengths of eMBMS multicast. In this work, we first identify and analyze several overlooked challenges for scheduling multicast traffic in MBSFNs. Then we develop an effective and efficient dynamic scheduling algorithm for eMBMS multicast in time and frequency varying channel. The proposed algorithm leverages the advantages of both multicast and unicast schemes via user grouping; and through extensive simulations, is shown to be capable of significantly enhancing the mission critical performances under both best effort and guaranteed bit rate delivery models. We also show the resiliency of our proposed algorithm by applying it onto various network and user deployment scenarios. Our consistent results further prove that LTE eMBMS in MBSFN is a key solution in overcoming limitations in near future public safety networks.

Joint optimization for broadcast service rendering and call connectivity for dual stack mobile devices

INTRODUCTION: Multimedia Broadcast Multicast Service (MBMS) primarily targets broadcasting mobile television contents and video streaming services. Consumers worldwide are rapidly using Dual SIM Dual Standby (DSDS) device that utilizes a single common Radio Frequency Integrated Circuit (RFIC) for su