Dynamic Slot Allocation Scheme Research Articles

Dynamic Slot Allocation Scheme in Tactical Multi-hop Networks for Future Soldier Systems

In this paper, we propose a dynamic slot allocation scheme to improve the slot utilization rate in tactical multi-hop networks in which the channel condition varies due to node movements. The proposed scheme takes advantage of the fact that nodes that are more than three hops apart can use the same slot simultaneously. The frame is divided into two parts: the control period and the data period. To know the available slot information within two-hop distance, the node exchanges a slot allocation information with one-hop neighbors during the control period. The node can get the information on idle slots that are not used within two-hop distance but assigned already to other nodes that are more than three-hop away. The identified idle slot can be used by the node, which increases the slot utilization rate. The performance analysis results of the proposed scheme show that it increases the slot utilization rate sufficiently despite the overhead of the control period in the multi-hop networks of the future soldier system. Keywords: ìŠ¬ë¡¯í• ë‹¹, ë™ì ì‹œë¶„í• ë‹¤ì¤‘ì ‘ì†, ì „ìˆ ë‹¤ì¤‘í™‰ 네트워크, ë§¤ì²´ì ‘ê·¼í†µì œ, ê°œì¸ì „íˆ¬ì²´ê³„ Keywords: Slot Allocation, Dynamic TDMA, Tactical Multi-hop Networks, MAC, Future Soldier System

Dynamic Slot Allocation Using Non Overlapping Backoff Algorithm in IEEE 802.15.6 WBAN

A dynamic slot allocation scheme using non-overlapping contention windows is presented in this paper to improve the utilization of the IEEE 802.15.6 Wireless Body Area Network (WBAN) superframe. Firstly, a Non Overlapping Backoff Algorithm (NOBA) that avoids inter-priority collisions due to backoff is presented. The results of this scheme are compared with the standard Binary Exponential Backoff (BEB) and the Prioritized Fibonacci Backoff (PFB) schemes. The NOBA provides improvement in the sum throughput, individual throughputs and access delay. Secondly, to avoid the wastage due to fixed slot size, a Dynamic Slot Allocation (DSA) scheme is introduced. It assigns the dynamic slots and phases in a superframe depending on the traffic requirements. Thirdly, a DSA-NOBA scheme that combines both the DSA and the NOBA is presented. The performance of DSA-NOBA is compared against the standard IEEE 802.15.6 superframe (with BEB) and Dynamic Phase Allocation (DPA) schemes using the individual throughput, sum throughput, latency, energy, superframe time and superframe efficiency as performance metrics. Over a range of payload sizes, the DSA-NOBA makes the superframe 50% more efficient than the standard IEEE 802.15.6 superframe with BEB, consequently also providing improvement in all the performance metrics. The most notable among them is energy, whose consumption is reduced by half when compared with the standard.

Spectrum Sensing and Resource Allocation for Proficient Transmission in Cognitive Radio with 5G

In orthogonal frequency division multiplexing (OFDM)-based cognitive radio network–cooperative spectrum sensing (CRN-CSS), resource allocation is critical due to the introduction of interference during spectrum sensing and transmission. This paper resolves this problem of interference through proficient spectrum sensing and resource allocation to improve data transmission. CRN-CSS network is integrated with 5G supported by multiple-input–multiple-output equipped fusion center (FC) to handle massive number of users without loss in connectivity. OFDM-based data transmission is adapted in CRN-CSS to achieve a better transmission rate. In the integrated network, grouping process is initiated by a balanced K-means clustering algorithm to preserve cooperation among secondary users (SUs). Dynamic slot allocation scheme, two-stage multi-slot channel assignment method, is proposed to avoid interference during spectrum sensing. Sensing errors are minimized with the assistance of the energy spectral density-based energy detection spectrum sensing method. For global decision-making, the channel state weighted graph scheme is introduced in which spectrum agent plays a vital role. Finally, resource allocation is carried out by the FC by utilizing efficient Karush–Kuhn–Tucker (EKKT) conditions. Through EKKT method spectrum, transmission powers are allocated to SUs together in such a way that interference with primary user is avoided. Meanwhile, OFDM-based transmission with quadrature phase shift keying modulation scheme reduces peak-to-average-power ratio that leads to high transmission rate. The proposed network is extensively simulated in the NS-3.26 simulation tool and the performance is evaluated from the following performance metrics: throughput, capacity, network utility, transmission power, and transmission rate.