Business Case and Technology Analysis for 5G Low Latency Applications

A large number of new consumer and industrial applications are likely to change the classic operator's business models and provide a wide range of new markets to enter. This article analyses the most relevant 5G use cases that require ultra-low latency, from both technical and business perspectives. Low latency services pose challenging requirements to the network, and to fulfill them operators need to invest in costly changes in their network. In this sense, it is not clear whether such investments are going to be amortized with these new business models. In light of this, specific applications and requirements are described and the potential market benefits for operators are analysed. Conclusions show that operators have clear opportunities to add value and position themselves strongly with the increasing number of services to be provided by 5G.Comment: 18 pages, 5 figure

Error resilient packet switched H.264 video telephony over third generation networks.

Real-time video communication over wireless networks is a challenging problem because wireless channels suffer from fading, additive noise and interference, which translate into packet loss and delay. Since modern video encoders deliver video packets with decoding dependencies, packet loss and delay can significantly degrade the video quality at the receiver. Many error resilience mechanisms have been proposed to combat packet loss in wireless networks, but only a few were specifically designed for packet switched video telephony over Third Generation (3G) networks. The first part of the thesis presents an error resilience technique for packet switched video telephony that combines application layer Forward Error Correction (FEC) with rateless codes, Reference Picture Selection (RPS) and cross layer optimization. Rateless codes have lower encoding and decoding computational complexity compared to traditional error correcting codes. One can use them on complexity constrained hand-held devices. Also, their redundancy does not need to be fixed in advance and any number of encoded symbols can be generated on the fly. Reference picture selection is used to limit the effect of spatio-temporal error propagation. Limiting the effect of spatio-temporal error propagation results in better video quality. Cross layer optimization is used to minimize the data loss at the application layer when data is lost at the data link layer. Experimental results on a High Speed Packet Access (HSPA) network simulator for H.264 compressed standard video sequences show that the proposed technique achieves significant Peak Signal to Noise Ratio (PSNR) and Percentage Degraded Video Duration (PDVD) improvements over a state of the art error resilience technique known as Interactive Error Control (IEC), which is a combination of Error Tracking and feedback based Reference Picture Selection. The improvement is obtained at a cost of higher end-to-end delay. The proposed technique is improved by making the FEC (Rateless code) redundancy channel adaptive. Automatic Repeat Request (ARQ) is used to adjust the redundancy of the Rateless codes according to the channel conditions. Experimental results show that the channel adaptive scheme achieves significant PSNR and PDVD improvements over the static scheme for a simulated Long Term Evolution (LTE) network. In the third part of the thesis, the performance of the previous two schemes is improved by making the transmitter predict when rateless decoding will fail. In this case, reference picture selection is invoked early and transmission of encoded symbols for that source block is aborted. Simulations for an LTE network show that this results in video quality improvement and bandwidth savings. In the last part of the thesis, the performance of the adaptive technique is improved by exploiting the history of the wireless channel. In a Rayleigh fading wireless channel, the RLC-PDU losses are correlated under certain conditions. This correlation is exploited to adjust the redundancy of the Rateless code and results in higher Rateless code decoding success rate and higher video quality. Simulations for an LTE network show that the improvement was significant when the packet loss rate in the two wireless links was 10%. To facilitate the implementation of the proposed error resilience techniques in practical scenarios, RTP/UDP/IP level packetization schemes are also proposed for each error resilience technique. Compared to existing work, the proposed error resilience techniques provide better video quality. Also, more emphasis is given to implementation issues in 3G networks

On the Design of Sidelink for Cellular V2X: A Literature Review and Outlook for Future

Connected and fully automated vehicles are expected to revolutionize our mobility in the near future on a global scale, by significantly improving road safety, traffic efficiency, and traveling experience. Enhanced vehicular applications, such as cooperative sensing and maneuvering or vehicle platooning, heavily rely on direct connectivity among vehicles, which is enabled by sidelink communications. In order to set the ground for the core contribution of this paper, we first analyze the main streams of the cellular-vehicle-to-everything (C-V2X) technology evolution within the Third Generation Partnership Project (3GPP), with focus on the sidelink air interface. Then, we provide a comprehensive survey of the related literature, which is classified and critically dissected, considering both the Long-Term Evolution-based solutions and the 5G New Radio-based latest advancements that promise substantial improvements in terms of latency and reliability. The wide literature review is used as a basis to finally identify further challenges and perspectives, which may shape the C-V2X sidelink developments in the next-generation vehicles beyond 5G

Packet Scheduling Algorithms in LTE/LTE-A cellular Networks: Multi-agent Q-learning Approach

Spectrum utilization is vital for mobile operators. It ensures an efficient use of spectrum bands, especially when obtaining their license is highly expensive. Long Term Evolution (LTE), and LTE-Advanced (LTE-A) spectrum bands license were auctioned by the Federal Communication Commission (FCC) to mobile operators with hundreds of millions of dollars. In the first part of this dissertation, we study, analyze, and compare the QoS performance of QoS-aware/Channel-aware packet scheduling algorithms while using CA over LTE, and LTE-A heterogeneous cellular networks. This included a detailed study of the LTE/LTE-A cellular network and its features, and the modification of an open source LTE simulator in order to perform these QoS performance tests. In the second part of this dissertation, we aim to solve spectrum underutilization by proposing, implementing, and testing two novel multi-agent Q-learning-based packet scheduling algorithms for LTE cellular network. The Collaborative Competitive scheduling algorithm, and the Competitive Competitive scheduling algorithm. These algorithms schedule licensed users over the available radio resources and un-licensed users over spectrum holes. In conclusion, our results show that the spectrum band could be utilized by deploying efficient packet scheduling algorithms for licensed users, and can be further utilized by allowing unlicensed users to be scheduled on spectrum holes whenever they occur

On the Merits of Deploying TDM-based Next-Generation PON Solutions in the Access Arena As Multiservice, All Packet-Based 4G Mobile Backhaul RAN Architecture

The phenomenal growth of mobile backhaul capacity required to support the emerging fourth-generation (4G) traffic including mobile WiMAX, cellular Long-Term Evolution (LTE), and LTE-Advanced (LTE-A) requires rapid migration from today\u27s legacy circuit switched T1/E1 wireline and microwave backhaul technologies to a new fiber-supported, all-packet-based mobile backhaul infrastructure. Clearly, a cost effective fiber supported all-packet-based mobile backhaul radio access network (RAN) architecture that is compatible with these inherently distributed 4G RAN architectures is needed to efficiently scale current mobile backhaul networks. However, deploying a green fiber-based mobile backhaul infrastructure is a costly proposition mainly due to the significant cost associated with digging the trenches in which the fiber is to be laid. These, along with the inevitable trend towards all-IP/Ethernet transport protocols and packet switched networks, have prompted many carriers around the world to consider the potential of utilizing the existing fiber-based Passive Optical Network (PON) access infrastructure as an all-packet-based converged fixed-mobile optical access networking transport architecture to backhaul both mobile and typical wireline traffic. Passive Optical Network (PON)-based fiber-to-the-curb/home (FTTC/FTTH) access networks are being deployed around the globe based on two Time-Division Multiplexed (TDM) standards: ITU G.984 Gigabit PON (GPON) and IEEE 802.ah Ethernet PON (EPON). A PON connects a group of Optical Network Units (ONUs) located at the subscriber premises to an Optical Line Terminal (OLT) located at the service provider\u27s facility. It is the purpose of this thesis to examine the technological requirements and assess the performance analysis and feasibility for deploying TDM-based next-generation (NG) PON solutions in the access arena as multiservice, all packet-based 4G mobile backhaul RAN and/or converged fixed-mobile optical networking architecture. Specifically, this work proposes and devises a simple and cost-effective 10G-EPON-based 4G mobile backhaul RAN architecture that efficiently transports and supports a wide range of existing and emerging fixed-mobile advanced multimedia applications and services along with the diverse quality of service (QoS), rate, and reliability requirements set by these services. The techno-economics merits of utilizing PON-based 4G RAN architecture versus that of traditional 4G (mobile WiMAX and LTE) RAN will be thoroughly examine and quantified. To achieve our objective, we utilize the existing fiber-based PON access infrastructure with novel ring-based distribution access network and wireless-enabled OLT and ONUs as the multiservice packet-based 4G mobile backhaul RAN infrastructure. Specifically, to simplify the implementation of such a complex undertaking, this work is divided into two sequential phases. In the first phase, we examine and quantify the overall performance of the standalone ring-based 10G-EPON architecture (just the wireline part without overlaying/incorporating the wireless part (4G RAN)) via modeling and simulations. We then assemble the basic building blocks, components, and sub-systems required to build up a proof-of-concept prototype testbed for the standalone ring-based EPON architecture. The testbed will be used to verify and demonstrate the performance of the standalone architecture, specifically, in terms of power budget, scalability, and reach. In the second phase, we develop an integrated framework for the efficient interworking between the two wireline PON and 4G mobile access technologies, particularly, in terms of unified network control and management (NCM) operations. Specifically, we address the key technical challenges associated with tailoring a typically centralized PON-based access architecture to interwork with and support a distributed 4G RAN architecture and associated radio NCM operations. This is achieved via introducing and developing several salient-networking innovations that collectively enable the standalone EPON architecture to support a fully distributed 4G mobile backhaul RAN and/or a truly unified NG-PON-4G access networking architecture. These include a fully distributed control plane that enables intercommunication among the access nodes (ONUs/BSs) as well as signaling, scheduling algorithms, and handoff procedures that operate in a distributed manner. Overall, the proposed NG-PON architecture constitutes a complete networking paradigm shift from the typically centralized PON\u27s architecture and OLT-based NCM operations to a new disruptive fully distributed PON\u27s architecture and NCM operations in which all the typically centralized OLT-based PON\u27s NCM operations are migrated to and independently implemented by the access nodes (ONUs) in a distributed manner. This requires migrating most of the typically centralized wireline and radio control and user-plane functionalities such as dynamic bandwidth allocation (DBA), queue management and packet scheduling, handover control, radio resource management, admission control, etc., typically implemented in today\u27s OLT/RNC, to the access nodes (ONUs/4G BSs). It is shown that the overall performance of the proposed EPON-based 4G backhaul including both the RAN and Mobile Packet Core (MPC) {Evolved Packet Core (EPC) per 3GPP LTE\u27s standard} is significantly augmented compared to that of the typical 4G RAN, specifically, in terms of handoff capability, signaling overhead, overall network throughput and latency, and QoS support. Furthermore, the proposed architecture enables redistributing some of the intelligence and NCM operations currently centralized in the MPC platform out into the access nodes of the mobile RAN. Specifically, as this work will show, it enables offloading sizable fraction of the mobile signaling as well as actual local upstream traffic transport and processing (LTE bearers switch/set-up, retain, and tear-down and associated signaling commands from the BSs to the EPC and vice-versa) from the EPC to the access nodes (ONUs/BSs). This has a significant impact on the performance of the EPC. First, it frees up a sizable fraction of the badly needed network resources as well as processing on the overloaded centralized serving nodes (AGW) in the MPC. Second, it frees up capacity and sessions on the typically congested mobile backhaul from the BSs to the EPC and vice-versa

Unmanned Aerial Vehicle (UAV)-Enabled Wireless Communications and Networking

The emerging massive density of human-held and machine-type nodes implies larger traffic deviatiolns in the future than we are facing today. In the future, the network will be characterized by a high degree of flexibility, allowing it to adapt smoothly, autonomously, and efficiently to the quickly changing traffic demands both in time and space. This flexibility cannot be achieved when the network’s infrastructure remains static. To this end, the topic of UAVs (unmanned aerial vehicles) have enabled wireless communications, and networking has received increased attention. As mentioned above, the network must serve a massive density of nodes that can be either human-held (user devices) or machine-type nodes (sensors). If we wish to properly serve these nodes and optimize their data, a proper wireless connection is fundamental. This can be achieved by using UAV-enabled communication and networks. This Special Issue addresses the many existing issues that still exist to allow UAV-enabled wireless communications and networking to be properly rolled out