High-throughput optical inter-board interconnects for next-generation on-board digital transparent processors

LTE over unlicensed spectrum (LTE-U) is one of the promising approaches to further improve LTE network throughput. To maximize the benefit of LTE-U, in this work we study joint resource allocation for LTE over the legacy licensed spectrum and the sharing unlicensed spectrum in a multi-cell scenario. Specifically, we formulate a mixed-integer power-channel allocation problem aiming at maximizing the network throughput, with the constraints of protecting the coexisting Wi-Fi networks and hardware limitation of user equipments in the LTE-U networks. To solve the resource allocation problem efficiently, we exploit delay column generation approach to decompose the original optimization problem and then propose a novel algorithm based KKT conditions. Simulation results show the advantage of LTE-U networking and the effectiveness of the proposed algorithm in terms of convergence speed and network throughput.

Femto cell deployment creates a pre-dominate effects in the world of Long Terminal Evolution-Advanced (LTE-A). Such deployment in Marco cell will enhance the coverage up to a large extends into building premise. Also, it doesn't need any frequency planning. However, major concern with respect to the Femto deployment is its resource allocations along with Marco and mobility of Home evolved NodeB (HeNodeB) at the building premises. This Paper suggests a method of scheduling in Femto-Marco cell when frequent handover occur at the pedestrian speeds. This demands an improved scheduling in Marco cell and Femto cell. Hence, in this paper we investigate scheduling techniques, namely, Fair Proportion (FP), Modified-Largest Weighted Delay First (MLWDF) and Exponential Scheduling (ES). The performance of the network is analyses in term of spectral efficiency, throughput and delay, found to be more effective compare to existing method used in literature. Combined MLWDF-ES has 38% better spectral efficiency compared to the literature value.

With the increasing demand for vehicular data transmission, limited dedicated cellular spectrum becomes a bottleneck to satisfying the requirements of all cellular vehicle-to-everything (V2X) users. To address this issue, unlicensed spectrum is considered to serve as the complement to support cellular V2X users. In this paper, we study the coexistence problem of cellular V2X users and vehicular ad hoc network (VANET) users over the unlicensed spectrum. To facilitate the coexistence, we design an energy sensing-based spectrum sharing scheme, where cellular V2X users are able to access the unlicensed channels fairly while reducing the data transmission collisions between cellular V2X and VANET users. In order to maximize the number of active cellular V2X users, we formulate the scheduling and resource allocation problem as a two-sided many-to-many matching with peer effects. We then propose a dynamic vehicle-resource matching algorithm and present the analytical results on the convergence time and computational complexity. Simulation results show that the proposed algorithm outperforms existing approaches in terms of the performance of the cellular V2X system when the unlicensed spectrum is utilized.

With an ever increasing demand for data, better and efficient spectrum operation has become crucial in cellular networks. In this paper, we present a detailed survey of various resource allocation schemes that have been considered for the cellular network’s operation in the unlicensed spectrum. The key channel access mechanisms for cellular network’s operation in the unlicensed bands are discussed. The various channel selection techniques are explored and their operation explained. The prime issue of fairness between cellular and Wi-Fi networks is discussed, along with suitable resource allocation techniques that help in achieving this fairness. We analyze the coverage, capacity, and impact of coordination in LTE-U systems. Furthermore, we study and discuss the impact and discussed the impact of various traffic type, environments, latency, handover, and scenarios on LTE-U’s performance. The new upcoming 5G New Radio and MulteFire is briefly described along with some of the critical aspects of LTE-U which require further research.

Resource allocation and trajectory optimization for air-ground MEC systems with dual connectivity in unlicensed spectrum

The ever-increasing demand for wireless communication has driven the development of innovative technologies to address the issues that conventional communication networks meet. To support autonomous devices in the sixth-generation (6G) and provide seamless wireless connectivity in inaccessible and hard-to-reach areas, the combination of software-defined networking (SDN) with unmanned aerial vehicles (UAVs) has already shown promises. As the traditional UAV-based cellular network encompasses challenges such as lack of centralized supervision, robust decision-making ability, and dynamic network management, the SDN platform could be an excellent alternative to offer aerial networking for future 6G ecosystem. However, the SDN-assisted UAV paradigm faces a set of challenges and critical issues. For instance, the network management and orchestration, resource allocation and optimization, handover mechanism, spectrum management, energy efficiency, integration of heterogeneous networks, and reliability, thus causing the decrease of quality of services of the SDN-enables UAV networks. To effectively address all these issues and identify the trends of software-defined UAV (SDUAV) networks, more research activities are needed. Unfortunately, there are not any specific guidelines in the literature that address each of these requirements, enabling technologies, emerging techniques, and future research directions in the context of SDN-based UAV networks to enable next-generation 6G systems. Therefore, motivated by this fact, this paper offers a comprehensive evaluation of the state of the SDUAV network and architecture, highlighting its various requirements and different prospects and applications in 6G systems. Besides, this paper also addresses why the combination of SDN and UAV-enabled networks is becoming essential in the 6G networking context and how it can offer more flexibility, scalability, reliability, and efficient connectivity than the conventional approaches to provide features like intelligence, automation, programmability, and centralized controllability. This paper furthermore outlines the difficulties of implementing SDUAV networks, such as security, adaptability, interference management, interoperability, and lack of standardization. Finally, to accomplish the goals, this article provides a roadmap for future trends and research directions in SDUAV networks to support the 6G systems.

In the heterogeneous networks (HetNets), finite spectrum resources limit the improve of network performance. Increased energy consumption also draws attention to the green communications. In this paper, we study the resource allocation and energy management problem for orthogonal frequency division multiple access (OFDMA)-based HetNets powered by hybrid energy, i.e. renewable energy and on-grid energy. To achieve the fairness among small cell BSs (SBSs) and also improve spectrum utilization, SBSs can share their own spectrum bands to others. To tackle the time-varying events in networks, we use Laypunov optimization method to develop an online dynamic control algorithm (ODCA), whose objective is to maximize the transmission and sharing profits with the least grid energy consumption. The proposed algorithm decompose the problem into three sub-problems: admitted rate control, resource allocation, and energy management. In the resource allocation sub-problem, we first establish a two-SBS bargaining problem to achieve the spectrum sharing and then extend it to a multiple-SBS bargaining problem. Simulation results are presented to demonstrate the effectiveness of the proposed scheme.

We consider the problem of optimizing video delivery for a network supporting video clients streaming stored video. Specifically, we consider the joint optimization of network resource allocation and video quality adaptation. Our objective is to fairly maximize video clients' Quality of Experience (QoE) realizing tradeoffs among the mean quality, temporal variability in quality, and fairness, incorporating user preferences on rebuffering and cost of video delivery. We present a simple asymptotically optimal online algorithm, NOVA, to solve the problem. NOVA is asynchronous, and using minimal communication, distributes the tasks of resource allocation to network controller, and quality adaptation to respective video clients. Video quality adaptation in NOVA is also optimal for standalone video clients, and is well suited for use in the DASH framework. Further, NOVA can be extended for use with more general QoE models, networks shared with other traffic loads and networks using fixed/legacy resource allocation.

The balanced distribution of multimedia wireless network modular teaching resources is improved by optimizing and adjusting the balanced distribution of multimedia wireless network modular teaching resources. Based on block grid balanced scheduling and resource spectrum fusion, a balanced distribution method of multimedia wireless network modular teaching resources is proposed. A blockchain Internet of Things accesses control network architecture system for the balanced allocation of multimedia wireless network modular teaching resources established using the priority business scheduling method. Modular resource allocation of multimedia wireless networks and adaptive forwarding are adjusted to control the data packets. The bandwidth guarantee mechanism is used for the equitable allocation of multimedia wireless network modular teaching resources information flow. Multi-service hierarchical management of multimedia wireless network modular teaching resources spectrum is controlled by block grid balanced scheduling and resource spectrum fusion. The high-energy physical computing system structure is used to allocate the resource spectrum balance of the modular teaching resources of the multimedia wireless networks, ensuring the bandwidth requirements of various services. The classified management and balanced allocation of the multimedia wireless networks’ teaching storage, system, and teaching spectrum resources are made possible. The results of the tests show that this method effectively reduces the delay in the allocation of modular multimedia wireless network teaching resources, improves the utilization rate of modular multimedia wireless network teaching resources, and significantly improves their reading and writing performance.

We highlight the advantages of dynamic wavelength allocation and path rerouting in hybrid optical flow-switched data center networks compared with static electronic packet-switched data center networks. Current electronic packet-switched networks perform routing based on lookup tables and shortest path routing over high speed optical connections. However, load balancing and path rerouting are not designed in coordination with the optical data plane. In this work, we design and analyze the performance of load balancing and resource allocation in hybrid flow data center architectures. In the hybrid flow architecture, the transport layer and control plane are responsible for load balancing, congestion control and reliable data delivery in wavelength division multiplexed networks. The transport layer abstracts the underlying network and data link layers from user applications. Applications are unaware of whether flows are transmitted via the electronic data plane, optical data plane, or both, where the relevant metric for applications is transaction delay. We show that the data center architecture that minimizes delay in the presence of elephant flows and dynamic loads is the hybrid flow architecture with dynamic resource allocation.

BackgroundPublic hospitals in developing countries, rather than the preventive and primary healthcare sectors, are the major consumers of healthcare resources. Imbalances in rational, equitable and efficient allocation of scarce resources lie in the scarcity of research & information on economic aspects of health care. The objective of this study was to determine the average cost of a spontaneous vaginal delivery and Caesarean section in a tertiary level government hospital in Islamabad, Pakistan and to estimate the out of pocket expenditures to households using these services.MethodsThis hospital based cost accounting cross sectional study determines the average cost of vaginal delivery and Caesarean section from two perspectives, the patient's and the hospital. From the patient's perspective direct and indirect expenditures of 133 post-partum mothers (65 delivered by Caesarean section & 68 by spontaneous vaginal delivery) admitted in the maternity general ward were determined. From the hospital perspective the step down methodology was adopted, capital and recurrent costs were determined from inputs and cost centers.ResultsThe average cost for a spontaneous vaginal delivery from the hospital's side was 40 US$ (2688 rupees) and from the patient's perspective was 79 US$ (5278 rupees). The average cost for a Caesarean section from the hospital side was 162 US$ (10868 rupees) and 204 US$ (13678 rupees) from the patient's side. Average monthly household income was 141 ± 87 US$ for spontaneous vaginal delivery and 168 ± 97 US$ for Caesarean section. Three fourth (74%) of households had a monthly income of less than 149 US$ (10000 rupees).ConclusionThe apparently "free" maternity care at government hospitals involves substantial hidden and unpredicted costs. The anticipated fear of these unpredicted costs may be major factor for many poor households to seek cheaper alternate maternity healthcare.

Featuring unprecedentedly high data rates and high connection densities, 3GPP New Radio (NR) vehicle-to-everything (V2X) communications have been regarded as the most promising remedy to support the next generation driving use cases. For this purpose, although dedicated bands on 5.9 GHz spectrum have been allocated for Intelligent Transportation Systems (ITS), the limited bandwidth may not afford the desired service requirements. This engineering concern thus drives the utilization of unlicensed bands on 5 GHz spectrum adjacent to the ITS bands. However, subject to the fairness constraint in sharing unlicensed spectrum, various communication regulations have been imposed, and four different types of multi-band channel access procedures are consequently developed both in 3GPP LTE-A Licensed-Assisted Access (LAA) and NR on unlicensed spectrum (NR-U), to lead to a phenomenon that occupying more unlicensed bands may not suggest a proportional growth in the throughput. To empower high-throughout and high-density V2X communications, in this paper, we consequently propose the optimum channel access strategies for each V2X transmitter to decide the optimum number of unlicensed bands to access. To this end, analytic models for four types of multi-band channel access procedures in 3GPP NR-U are provided, which capture both inter-system and intra-system interference from coexisting WiFi transmitters and V2X transmitters. Subsequently, game-theoretically optimum strategies for each type of multi-band channel access procedures are derived. Performance evaluation results fully demonstrate the optimality of the proposed strategies, to serve the urgent demands in supporting the next generation driving use cases on unlicensed spectrum.

The growing demand for spectrum resources and the limited licensed spectrum have led to widespread concern about the coexistence of LTE and WiFi in the unlicensed spectrum. Since LTE and WiFi are two different systems, many solutions have been proposed to solve their coexistence problems, including the coexistence scheme based on blank subframe allocation. This paper presents a scheme that uses Q-learning algorithm to dynamically allocate blank subframes so that both LTE-U and WiFi system can successfully coexist. To support the proposed scheme, we introduce a new LTE-U frame structure, which can not only allocate blank subframes but also reduce the LTE delay. Simulation results show that the proposed approach can effectively improve the overall system performance in terms of the utilization of spectrum.

This letter investigates the fair coexistence of sidelink (SL) communication and Wi-Fi network in unlicensed spectrum. A three-dimensional (3-D) network model is studied to accurately describe characteristics of the coexistence system in the indoor scenario of high-rise centers by utilizing stochastic geometry. First, the medium access probability of a typical SL transmitter or Wi-Fi access point (AP) is derived, and then the average spectral efficiency of an arbitrary device is calculated. Based on the theoretical analysis, a dynamic resource allocation scheme in duty-cycle based access mode is proposed to maximize the coexistence system throughput while guaranteeing fairness. The numerical results show the effectiveness of the proposed scheme.

The use of LTE-Unlicensed is a promising approach to aggregate both licensed and unlicensed spectrum bands, in an effort to meet the QoS of emerging wireless services. In this chapter, we investigate the problem of carrier aggregation between licensed and unlicensed spectrum by deploying LTE-Unlicensed enabled micro-cell base stations, which have access to the unlicensed spectrum, to provide cellular users a more reliable and efficient transmission. We address the unlicensed resource allocation problem by modeling it as a student-project allocation matching game. In addition, a post-matching procedure of resource re-allocation is introduced to guarantee unlicensed users’ QoS, as well as the system-wide stability. The simulation evaluation shows the effectiveness and efficiency of our investigated matching-based approach.