This article proposes a novel fair and scalable relay control (FSRC) scheme for the Internet-of-Things (IoT) services in long range (LoRa)-based low-power wide-area networks. The proposed FSRC scheme promotes relay operation with low spreading factor (SF) to improve the success probability for distant end-devices (EDs) and the fairness of success probability for each SF region. To achieve this, a theoretical framework for designing the relay operation is analytically developed by considering a practical LoRaWAN MAC protocol as an analytical model. The proposed FSRC scheme encompasses a selective relay operation by considering both signal-to-noise ratio and signal-to-interference ratio and the receive signal strength indicator value for the location-unaware relay selection strategy. Using this model, a genetic algorithm-based relay control strategy is proposed to maximize both coverage probability and minimum success probability for all SF regions by controlling the relay parameters, such as source-relay region and source-relay ratio. Our numerical analysis validates the effectiveness of the proposed FSRC scheme under various parameters in terms of the minimum success probability of each SF region, coverage probability, and fairness. Specifically, we verify that the proposed FSRC scheme achieves a maximum of approximately 37% and 33% improvement of the minimum success probability and coverage probability, respectively, under practical LoRa PHY/MAC parameters, compared to the single-hop environment (without relay operation).

We consider a new QoS framework for a wide range of multimedia services in ever-changing networks where traffic is dynamic and network topologies frequently change. In this paper, for such networks, we propose a new self-organizing QoS framework called AntQoS, which is inspired by recent works on ant colony optimization. Compared with previous QoS frameworks, AntQoS provides two quite promising capabilities: 1) the self-organized network QoS (not pre-defined QoS), which autonomously reconfigures itself by promptly adapting to changing network environments such as sudden arrivals of highly bursty traffic, and 2) the self-organized network controls, which autonomously resolve the network congestion and intrinsically resist the multiple network failures. These two promising capabilities enable the proposed AntQoS framework to efficiently and reliably support a wide range of multimedia services with various quality demands. Especially, these capabilities are provided by making use of swarm intelligence of artificial ants without any supervised control. For this purpose, AntQoS employs one single artificial ant colony on an ever-changing network; a number of artificial ants in the employed colony explore network and measure or gather the status information about the networks. Based on the gathered information, AntQoS organizes and maintains a small number of virtual sub colonies named QoS colonies. The QoS colony is an intelligent virtual colony to be capable of searching the path which guarantees the given quality demands of flows. In addition, it is autonomously generated, maintained, and deleted for promptly adapting to the ever-changing network status. Simulation results demonstrate that AntQoS successfully supports various multimedia services with diverse delay requirements while increasing the network throughput by approximately 20% compared to the well-known IntServ frameworks. Simulation results also show that AntQoS autonomously redistributes the congested traffic and resists the unexpected network failures.

Achieving the benefits of high-capacity of optical networks and the mobility feature of wireless networks leads to integrate EPON and WiMAX for a promising broadband access solution. To efficiently put both benefits together, we propose an integration architecture of EPON-WiMAX based upon a Distributed Antenna (DA) environment, where collaborative Base Stations (BSs) concurrently transmit same wireless downlink signals (specifically for multicast and broadcast services (MBSs)) to Mobile Stations (MSs) in overlapped cell coverage areas. It helps enlarge the region of the available network coverage area by increasing Signal to Interference and Noise Ratio (SINR) in overlapped cell coverage areas through cooperation between Optical Line Terminal (OLT) and Optical Network Unit (ONU)- BS. We also present an cost-efficient cell planning to optimally control the size of overlapped cell coverage areas for the proposed DA-based integration architecture with a case study under a required region of the available network coverage area in consideration of the number of ONU-BSs and the distance between ONU-BSs. Performance evaluation results show that the proposed DA-based integration architecture enhances cost efficiency compared to the Traditional Antenna (TA) (non-DA)-based integration architecture with a similar level of spectral efficiency of MSs.

This paper proposes an efficient fair queuing algorithm, called mean starting potential fair queuing (MSPFQ), which has O(l) complexity for the virtual time computation while it has delay and fairness properties similar to starting-potential fair queueing (SPFQ). The key idea of MSPFQ algorithm is that it recalibrates the system virtual time to the mean value of the minimum possible virtual start times of HOL packets in each backlogged session. Through analysis and simulation, this paper shows that the proposed algorithm has good delay and fairness properties.

Available bit rate and ATM block transfer capabilities are the essential ATM transfer capabilities to be implemented in the public network in respect of the traffic characteristics and bandwidth utilization. Therefore, one of two ATM transfer capabilities is implemented in the public switching system and the other ATM transfer capability can be accommodated using the interoperability mechanism. In this paper, we propose the interworking and emulation methods for the interoperability of available bit rate/ATM block transfer capability depending on the closed-loop range of each ATM transfer capability and also propose the block cell rate re-negotiation with state dependent mechanism based on the common buffer with two thresholds when the public switching system has the ATM block transfer capability. We analyze the performance of the block cell rate re-negotiation with state dependent mechanism from the view points of the maximum queue length and bandwidth utilization.