A review on delay-minimized routing protocol in mobile cognitive ad hoc networks

A review on delay-minimized routing protocol in mobile cognitive ad hoc networks Mobile Cognitive Ad Hoc Networks is one of the cognitive radio networks which is the advanced networking technologies for spectrum scarcity problem constrain in the Federal Communication Commission (FCC). The cognitive radio networks are the cognitive network which abjects its network parameters with respect to the network environment. In cognitive radio network two users namely the primary and secondary or cognitive users will access the available spectrum to communicate each other when the spectrum is accessed by the primary user the secondary user must leave the spectrum and access the spectrum when spectrum holes available for transmission. So routing is challenging issues in cognitive networks and it is very challenging in mobile cognitive networks due to the node mobility, primary user interface and spectrum scarcity in this paper some routing protocols based on mobile ad hoc cognitive networks and a review on the delay-Minimized routing protocol are presented. Cognitive Radio Networks (CRN) is the new technology used to overcome the spectrum scarcity problem in current wireless networks by the Federal Communication Commission (FCC). In cognitive radio network is a network which has primary and secondary users which access the network based on Dynamic Spectrum Access (DSA). The primary user is the licensed user and secondary user is unlicensed user when the licensed user is accessing the spectrum the unlicensed user are not allowed so the secondary user has to sense the spectrum periodically to find the presence of primary user, presence of primary user is in dynamic in nature so the spectrum holes created by primary user is dynamic so the Cognitive user uses the DSA. While using the DSA routing is the challenging in cognitive radio networks. Classification of Cognitive radio networks Cognitive Radio Networks (CRN) is of infrastructure and infrastructure less, in infrastructure network it has a fixed structure like base station primary users secondary users and so on, in infrastructure network it has no fixed structure. Centralized and Decentralized networks the Centralized network is the network in which has on the base station in the central and have primary users are present. The decentralized network is the network which has no centralized base station and has the secondary users to communicate and primary users Static and dynamic networks the static networks the position of the base station, primary users and secondary users are fixed but in the dynamic (Ad-Hoc) the position on primary users and the secondary user will change (Mobility is nature). Routing in Cognitive radio networks Routing in Cognitive radio networks is based on available spectrum and knowledge of spectrum to nodes in the network. Routing solutions for the Cognitive radio networks are of two types one is Full Spectrum Knowledge routing and second is Local Spectrum Knowledge routing. Local Spectrum Knowledge routing has Minimum Power Routing, Minimum Delay-based Routing, Maximum Throughput-based Routing, Geographic Routing and Class-based Routing. Spectrum-Aware Routing (SPEAR) Spectrum-Aware Routing (SPEAR) is an on-demand and link-based protocol support end-to-end throughput by integration of flow-based and link-based approaches, it used RREQ for route discovery by control channels it takes decisions with the collaboration of PHY and MAC layers it handles mobility issues with Timeout field in periodic channel reservations messages. It takes the best path by maximum throughput, minimum hop count and link quality it has a communication overhead by route setup and route tear down. Spectrum-Aware Mesh Routing (SAMER) Spectrum-Aware Mesh Routing (SAMER) is a link state routing protocol with a minimum hop count and spectrum availability it gives end-to-end thought with the path with high spectrum availability, long-term stability and short-term opportunistic utilization of spectrum. The routing decisions are taken by PHY and MAC layers. Spectrum-Aware On-Demand Routing Protocol (SORP) Spectrum-Aware On-Demand Routing Protocol (SORP) is an AODV protocol with control channel which uses the path delay and node delay (switching and back off delay) for path selection. In route discovery phase RREQ message is broadcast with an SOP append in the packet the control channel exchange the routing protocol messages and it gives end-to-end thought put SORP doesn’t have link failure handling mechanism. Multi-hop Signal-transceiver Cognitive Radio Network Routing Protocol (MSCRP) Multi-hop Signal-transceiver Cognitive Radio Network Routing Protocol (MSCRP) is an AODV protocol with on control channel. It is a spectrum aware routing and leaves/ joins messages of the nodes so it has the communication overhead of RREQ. In the route discovery phase, all nodes append their sate information and available channels set. The routing decision is taken with the collaboration of MA C, Physical and Network Layers. Routing in Opportunistic Cognitive Radio Networks Routing in Opportunistic Cognitive Radio Networks is an on-demand graph-structured network protocol which uses the routing metric based on the probabilistic definition of available capacity over channel it has no link failure handling capacity and it discovers the route by using OSPF, Dijkstra-link algorithm. By using this Dijkstra-link algorithm it gives end-to-end throughput Local Coordination Based Routing and Spectrum assignment in Multi-hop Cognitive Radio Networks Local Coordination Based Routing and Spectrum assignment in Multi-hop Cognitive Radio Networks is a modified version of AODV which is on-demand routing protocol it has full mesh topology which uses channel scanning and beacon broadcast for neighbor discovery with control channel used for load balancing in routing. The route discovery is done by using RREQ and route decision is based on MAC and Network Layer. It has a link failure handling capability which gives less end-to-end delay and performance. Multipath Routing and Spectrum Access (MRSA) Multipath Routing and Spectrum Access (MRSA) is Mesh routing protocol based on round robin fashion data striping with minimum hop count by route discovery with control channel, Broadcasting RREQ messages. The messages sent to nodes periodically it can handle path failures by sending RERR messages and it has a communication overhead based on multiple flows on a single radio. Cognitive Tree-based Routing (CTBR) Cognitive Tree-based Routing (CTBR) is the tree-based routing protocol with centralized routing it broadcast the root announcement (RANN) message periodically with a packet and used cumulative metric for path selection. It selects the path based on local and global decision schemes. It does not have a route recovery mechanism to handle link failure s and it has a control bytes transmission overhead. Fault-Tolerant Cognitive Ad-Hoc Routing Protocol (FTCARP) It is a fast and efficient routing protocol for route recovery in presence of path failures during data delivery. It uses different route recovery mechanisms for different path failures. Cognitive Destination Sequence Distance Vector (C-DSDV) Protocol It is a table-driven routing protocol. To optimize the system performance of multi-hop CR ad-hoc networks by using multichannel routing table are updated immediately when there is a change in channels the techniques is that combines the routing and channel allocation. In route discover phase common control channel use to broadcast the route updating in the routing table in this protocol best path selection is based on sequence number. In C-DSDV channel switching is used to improve the system performances. If there are more primary users routing overhead will be increased Cognitive Ad-Hoc On-demand Distance Vector (C-AODV) Protocol Cognitive Ad-Hoc On-demand Distance Vector (C-AODV) Protocol is based on AODV a wireless network protocol it is designed according to avoid primary users activates regains for routing formation and packet discovery. It gives the minimized route cost by forwarding packets through the joint pat h and channel selection at each node it takes the advantage of the availability of multiple channels to improve the overall performances. SER-Spectrum and Energy Aware Routing Protocol SER is an on-demand routing protocol which provides high throughput in multi-hop networks it selects an energy efficient route and assigns channels and timeslots for a connection request. The communication segment assignment algorithm is used for balances traffic load among the CR users. In route discovery phase it broadcasts Route Request Messages to other nodes so it has routing overhead of RRE, RREP, RERR and ROP messages. GYMKHANA Protocol GYMKHANA is an on-demand routing protocol and an enhanced version of AODV used the GYMKHANA algorithm using virtual graphs and evaluate the cost by using the Laplacian matrix. It has a secondary user’s self-interference overhead. UNITED NODE Protocol UNITED NODE Protocol is a distributed and efficient based interference-aware routing protocol. It incorporates the spectrum availability cost and interference metrics into the routing algorithm to find better routes between the nodes it repairs routes by using route preservation method. It provides adaptability to the environment and increases throughput and reduces data delivery latency. DELAY-MINIMIZED ROUTING PROTOCOLS FOR MOBILE COGNITIVE RADIO Ad-Hoc NETWORKS POPCORN Protocol ROPCORN Protocol is the on-demand routing protocol which was designed for data transportation using link modeling and used to minimized delay for a set of users in the network. It broadcast the packets in link with the low cost and no primary user is affected. POPCORN is based on RACON protocol it uses buffers in the intermediate nodes and forwards the packets there is no overhead due to the use of spectrum availability and load estimation, the optimal route selection is based on the spatial or temporal locality of link disconnection. SEARCH A Routing Protocol It is the on-demand routing protocol and an enhanced version of AODV which is based on the geographic routing and follows the greedy forwarding and PU avoidance for joint channel-path optimization algorithm to find the best path. SEARCH undertakes both the path and selection to avoid PU activity region and tries to maintain end-to-end latency it has routing overhead due to the RRE, RREP, RERR and ROP messages. Link Prediction-Based Ad aptive Routing Link Prediction-Based Adaptive Routing is based on the link-availability prediction. The link –availability prediction considers primary user activity and user mobility. This routing reduces the energy consumption and gives the least delay by enhances network performance. It works based on link prediction and topology control Joint Routing and Channel Assignment Joint Routing and Channel Assignment (JRCA) approach based on delay prediction and a heuristic algorithm which used the collision probability and Link Stability Prediction. It is an on-demand routing protocol which user AODV type of routing with heuristic values and can find out the path with minimal end-to-end (e2e) delay. Adaptive Delay Tolerant Routing Protocol (ADTRP) The ADTRP algorithm finds a stable sequence of instances of the mobile graph and the communication topology of interest such that the number of transitions from one instance of the topology to another in the sequence is the global minimum. The algorithm uses the average lifetime of the mobile graphs in the stable sequence for communication topology and it is a generic for a stable sequence of any communication topology it uses the heuristic topology for routing so it improved throughput, better packet delivery ratio, decreased packet drop and reduced delay. STOD-RP: A Spectrum-Tree Based On-Demand Routing Protocol STOD-RP is an on-demand routing protocol which was designed for reduces the control overhead and average end-t-end delay minimization and it is an extension of the original Ad-hoc On-demand Distance Vector (AODV) protocol which uses spectrum tree addresses, spectrum decision and route selection in an efficient way for this route matrix is used. Fast and efficient spectrum-adaptive route recovery method is used when the path is damaged. In routing is challenging issues in cognitive networks and it is very challenging in mobile cognitive networks due to the node mobility primary user interface and spectrum scarcity this paper concludes that every protocol is designed for overcome certain problem in networks one is for multiple problems and one is for single problem like improving performance, minimized end-to-end delay, overall throughput increasing and so on. There is a for more protocols or improved versions of protocols for increasing problems and recruitments. In further work on this paper, a delay minimized routing protocol is proposed and implemented that improved version protocol in NS3 will be presented

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