Dynamic Carrier Allocation Research Articles

Filter Distortions in Ultra High-Throughput Satellites: Models, Parameters and Multicarrier Optimization

Ultra high-throughput satellite systems are expected to play an essential role in future beyond 5G and 6G networks. These systems must remain as flexible as possible to adapt to heterogeneous traffic demands, while also delivering the highest possible rate for dedicated services. Satellites flexible payloads are increasingly employing wideband output multiplexers. In this context, it is now more important than ever to evaluate frequency-dependent degradations on multicarrier signals. In particular, it is critical to characterize the distortions entailed by the output multiplexers filters. In this paper, models are presented and novel formulas are derived to determine the carrier-to-interference ratio resulting from these distortions. Derivations are oriented towards the applicability of either high-accuracy (e.g., for link budget) or low-complexity calculations (e.g., for real-time carrier allocation). The influence of key parameters such as the optimal decision instant, symbol rate and roll-off factor is thoroughly analyzed. Furthermore, formulas are evaluated in a practical scenario: the dynamic carrier allocation optimization. They are combined with efficient optimization algorithms to obtain the best performance based on user fairness. Relevant metrics such as accuracy, complexity and allocation gain are also investigated. In the end, the application of the proposed formulas and algorithms leads to a significant allocation gain that is increasing with the number of carriers. The feasibility of real-time dynamic carrier allocation to further increase the capacity of the next generation of satellite systems is emphasized.

Dynamic Bandwidth and Carrier Allocation for Video Broadcast/Multicast Over Multi-Cell Environments

Recently, broadcast/multicast over cellular networks has been actively discussed over commercial wireless mobile terminals. Compared to conventional terrestrial or satellite broadcasting systems, the quality-of-service (QoS) for edge users is an important issue due to inter-cell interference over multi-cell environments. In this paper, we introduce a dynamic bandwidth and carrier allocation (DBCA) technique by fully utilizing different visual importance of each layer in multi-layer video for broadcast/multicast services when the number of users is limited over macro/micro/femto cell environments. To ensure an acceptable video quality for edge users, the bandwidth and the loading ratio are dynamically controlled to enhance the utility through the radio resource control in accordance with the visual importance. The simulation results show that DBCA exhibits much better QoS by sending visually more important data with high priority in the cell border region.

Location-based QoS enhanced dynamic carrier allocation over multi-cell environments

It is well known that high multi-user and multi-carrier diversity gains can be achieved via the use of DCA (Dynamic Channel Allocation). However, there is no framework for analyzing the system performance of DCA algorithms over multi-cell environments. This paper presents a numerical analysis for measuring the performance gain for various DCA algorithms. Based on the analysis, an LQE (Location-based QoS Enhanced) DCA algorithm is proposed, in which a higher priority is assigned to users in the outer region for fairness by exploiting multi-carrier diversity. In the inner region, each carrier is allocated to a user with the best channel gain for higher throughput by exploiting multi-user diversity. In the simulation, we demonstrate that the proposed DCA algorithm is very effective from the perspective of fairness and throughput.

Performance Gain Analysis of Dynamic Carrier Allocation Using Order Statistics

It is well known that the diversity gain attained by DCA (Dynamic Channel Allocation) is generally very high over OFDM (Orthogonal Frequency Division Multiplexing)-based broadband networks. This paper introduces a numerical approach for measuring the performance gain afforded by DCA. In the mathematical analysis, the property of order statistics is adopted to derive the upper bound of the expected throughput via the use of DCA. In the simulation, it was possible to achieve a gain of 5 dB by exploiting multi-user and spectral diversities when the number of users is 16 and the total number of subcarriers is 256.

Control of the Interworking Between Packet Reservation Multiple Access and Dynamic Carrier Allocation

This work deals with an enhanced frequency division multiplex/packet reservation multiple access (FDM/PRMA) technique for cellular systems also suitable for wireless local area networks (WLANs); such enhancements consist of an efficient control of the interworking between dynamic carrier allocation (DCA) strategies, which guarantee a real-time rearrangement of the carriers-to-cells assignment and PRMA techniques. This allows a higher carrier exploitation. In this respect, the novelties introduced in this paper are: (i) the definition of a short-term packet dropping probability which permits the real-time assessment of the link quality of a PRMA carrier; (ii) the determination of a procedure the base station (BS) can follow in order to perform a real-time estimation of the above-mentioned short-term parameter; (iii) an efficient carrier management and interworking between the DCA mechanism and the PRMA technique realized by means of such parameter. The paper also shows simulation results highlighting a remarkable improvement of the carrier utilization, obtained by the proposed interworking of the DCA and PRMA techniques.

Dynamic Carrier Allocation Strategies for Mobile Cellular Networks

Dynamic carrier allocation (DCA) refers to the paradigm of dynamically allocating carriers to cells in cellular networks. Many strategies have been proposed. In most of the strategies, each carrier is assigned a priority. Depending on how priorities are assigned, DCA strategies are classified into three categories: static-priority, dynamic-priority, and hybrid-priority strategies. In this paper, we investigate the concept of optimal reuse pattern, propose a model for resource planning, and propose three guidelines for priority assignment in static- and hybrid-priority DCA strategies. These theoretical results shed light on the strength and weakness of existing DCA strategies and lead us to develop more efficient strategies. Specifically, we propose three DCA strategies: column-wise static-priority, column-wise hybrid- priority, and two-step dynamic-priority. We study their performances by simulation under both uniform and nonuniform traffic distributions.

Performance evaluation of an improved PRMA protocol for low earth orbit mobile communication systems

Future mobile communication systems will be characterized by the interworking of several networks that will be integrated into a unique system. The satellite component and the terrestrial one will use as far as possible the same protocols. This work is concerned with Medium Access Control (MAC) protocols. In particular, Packet Reservation Multiple Access (PRMA) has been considered as a good candidate for terrestrial cellular systems, since it allows high multiplexing gains, dynamic PRMA carrier allocation to cells, easy management of integrated voice and data traffic and a near-transparent behaviour with respect to user mobility. The main aim of this preliminary work is to investigate the suitability of the PRMA protocol for application to Low Earth Orbit Mobile Satellite Systems (LEO-MSSs). Moreover, we have proposed a novel version of the PRMA protocol, named PRMA with Hindering States (PRMA-HS), that is particularly suitable for application in LEO systems. This new technique has shown very promising results in terms of both packet dropping probability and throughput. © 1997 John Wiley & Sons, Ltd.

Application of dynamic channel allocation strategies to the GSM cellular network

We refer to the implementation and the performance of a specific class of dynamic carrier allocation (DCA) strategies which is suitable for being introduced in the pan-European Global System for Mobile communications (GSM) cellular network. One of the main concerns of this work is to verify if and to what extent strategies belonging to this class can offer better performance than fixed channel allocation (FCA) in realistic traffic and propagation conditions. The impact of the introduction in a real network of two of the more promising DCA strategies in the considered class is assessed. In particular, solutions are presented concerning the signaling exchanges entailed by the implementation of each of the considered DCA strategies. A performance evaluation of a realistic cellular network exploiting the above-mentioned DCA strategies is carried out, taking into account all of the main GSM transmission and network aspects. The simulations have been performed by considering a realistic cell layout corresponding to the urban area of Rome, its realistic propagation environment, and a user mobility model based on the building percentages in such an area. The results of the performance evaluation show that, by carefully choosing the values of the parameters characterizing each of the considered DCA strategies, a conspicuous increase in the number of users supported by the cellular network can be achieved.

Dynamic allocation of packet reservation multiple access carriers

The author studies the performance of a high capacity metropolitan microcellular radio network using computer simulation. Packet reservation multiple access carriers are dynamically assigned or released depending on current teletraffic loading conditions. Significant performance improvements are obtained using a 2-stage costing strategy which attempts to balance call blocking probabilities against packet dropping rate, thereby leading to more efficient utilisation of channel resources. The author achieves 40 to 50% improvements over a fixed allocation scheme in terms of the blocking probability performance, by soft assigning carriers to the microcells and performing a 2-stage dynamic carrier allocation procedure based on a simple costing algorithm which attempts to pack co-carrier cells as closely as possible.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>