Dynamic Channel Allocation And Load Balancing With Sleep Scheduling In Manet

Transcription

1 International Journal of Science and Engineering Research (IJ0SER), Vol 3 Issue 9 September , (P) X Dynamic Channel Allocation And Load Balancing With Sleep Scheduling In Manet 1 R.Srividhya, 2 Ms.M.Sakthi 1 Research Scholar, 2 Professor and Head Department of Computer science N.G.M College,Pollachi, India Abstract Protocols that utilize the dynamic channel allocation and load balancing mechanisms to improve performance in terms of throughput, energy consumption and inter-packet delay variation (IPDV).Through extensive simulations, we show that both dynamic channel allocation and cooperative load balancing improve the bandwidth efficiency under non-uniform load distributions compared to protocols that do not use these mechanisms as well as compared to the IEEE protocol with GTS mechanism and the IEEE uncoordinated protocol. On-demand dynamic channel allocation used in cellular systems can be divided into two categories: centralized and distributed schemes. In centralized dynamic channel allocation schemes, the available channels are kept in a pool and distributed to various cells by a central coordinator which leads to higher overhead and cannot be applied to MANETs. In distributed dynamic channel allocation schemes, the available channels are distributed randomly according to the usage of the network which provides lower overheads with NS2 platform. It provides high bandwidth and low latency links between the cluster heads for coordination. Keywords dynamic channel allocation,idpv,load balancing,trace. I. INTRODUCTION An Adhoc network is a collection of mobile nodes, which forms a temporary network without the aid of centralized administration or standard support devices regularly available as conventional networks. These nodes generally have a limited transmission range and, so, each node seeks the assistance of its neighboring nodes in forwarding packets and hence the nodes in an Adhoc network can act as both routers and hosts. Thus a node may forward packets between other nodes as well as run user applications. By nature these types of networks are suitable for situations where either no fixed infrastructure exists or deploying network is not possible. Adhoc mobile networks have found many applications in various fields like military, emergency, conferencing and sensor networks. Introduction about networking A mobile ad-hoc network (MANET) is a group of mobile wireless nodes working together to form a network. Such networks can exist without a fixed infrastructure working in an autonomous manner and every mobile device has a maximum transmission power which determines the maximum transmission range of the device. As nodes are mobile, the link connection between the two devices can break depending on the spatial orientation of nodes. Mobile ad-hoc networks have numerous applications in mobile networks, disaster relief systems and military operations. Some of the network constraints in mobile ad-hoc networks are limited bandwidth, low battery power of nodes, and frequent link unreliability due to mobility. Cooperative load balancing in MANET Cooperative load balancing is a situation in communication networks in which too many packets are present in a part of the subnet. Cooperative load balancing may occur when the load on the network (number of packets send to the network) is greater than the capacity of the network (number of packets a network can handle). A cooperative load balancing leads to packet losses and bandwidth degradation and waste time and energy on cooperative load balancing. When cooperative load balancing occurs it is normally concentrated on a single router, whereas due to the shared medium of the MANET, cooperative load balancing will not overload the mobile nodes but has an effect on the entire coverage area. Cooperative load balancing Control in MANET Cooperative load balancing control is the main problem in adhoc networks. Cooperative load balancing control is associated with controlling traffic incoming in a telecommunication network. To avoid congestive crumple or link capabilities of the intermediate nodes and networks and to reduce the rate of sending packet cooperative load balancing control are used extensively. Cooperative load balancing control and dependability mechanisms are combined with Transports Control Protocol (TCP) to perform the cooperative load balancing control without explicit feedback about the cooperative load balancing position and without the Srividhya,Sakthi,. (IJ0SER) Septemberr

2 intermediate nodes being directly intermittent so cooperative communication has received tremendous interest for wireless networks. II. EXISTING SYSTEM The distributed dynamic channel allocation (DDCA) problem is to design a protocol for the cells to exchange information so as to acquire channels without violating the interference constraint. The goals are to avoid interference, minimize the call blocking and maximize bandwidth utilization and blocking probability is reduced as compared to dynamic channel allocation algorithm. Multicast Routing: Multicast Routing can be done in two approaches: (i)tree-based approaches These approaches create trees originating at the source and terminating at multicast group members with an objective of minimizing a cost function. (ii)mesh-based approaches - mesh-based approaches there is more than one path between the source and multicast group members.thus, even if one of the paths is broken due to mobility the other paths may be available. Load balancing wireless links of a gateway node that connects a wireless access network to the wired network. The gateway node co-ordinates the movement of all the nodes across the tree to achieve load balancing. In contrast, our load-balanced routing algorithm does not require such coordination or centralized computation. Various metrics have been proposed to measure an individual link load. In a wireless network using the number of packets or number of paths going through a particular node and its interference zone similarly measure the traffic going through each node, and compute the available bandwidth on different links of a path as well as on the gateway node to find a loadbalancing route. The channel assignment problem can actually be divided into two sub-problems: (i)neighbor-to-interface binding: Neighbor-to-interface binding determines through which interface a node uses to communicate with each of its neighbors with whom it intends to establish a virtual link. Because the number of interfaces per node is limited, each node typically uses one interface to communicate with multiple of its neighbors. (ii)interface-to-channel binding: Interface-to-channel binding determines which radio channel in a network interface should use the channel. The existing system faces the problem of scheduling the packet to the destination. The interference among packets by always rescheduling packet which finds the channel busy upon arrival and the ready terminal senses the channel and operates as follows: i) If the channel is sensed idle, it transmits the packet. ii) If the channel is sensed busy, then the terminal schedules the retransmission of the packet to some later time according to the retransmission delay distribution. At this new point in time it senses the channel and repeats. IEEE Standard There are two operation modes in the IEEE network, beacon enabled (slotted) and non-beacon enabled (un-slotted). In beacon enabled mode, communication is synchronized and controlled by a network coordinator, which transmits periodic beacons to define the start and the end of a super frame. The super frame may consist of active and inactive period; the active part of the super frame is divided into 16 equally sized slots and consists of 2 groups: the contention access period (CAP) and an optional contention free period (CFP). In the contention access period, slotted CSMA/CA is used as channel access mechanism, where the back off slot aligns with the start of beacon transmission. In the contention free period, time slots are assigned by the coordinator, devices which have been assigned specific time slots can transmit packets in this period. III.PROPOSED SYSTEM Dynamic channel allocation algorithm, channel coordinators react to the increasing local network load by increasing their share of bandwidth. Although being effective in providing support for non-uniform network loads, the reactive response taken by the channel coordinators increases the interference in the entire system. It also provides low latency links with an efficient communication with all the nodes of the network. Cooperative Load Balancing: The load on the channel coordinators originate from the demands of the ordinary nodes. Many nodes in a network have access to more than one channel coordinator. The underlying idea of the cooperative load balancing algorithm is that the active nodes can continuously monitor the load of the channel coordinators and switch from heavily loaded coordinators to the ones with available resources. These nodes can detect the depletion of the channels at the coordinator and shift their load to the other coordinators with more available resources. The resources vacated by the nodes that switch can be used for other nodes that do not have access to any other channel coordinators. It increases the total number

3 of nodes that access the channel and hence increases the service rate and the throughput. Single transceiver: The nodes in the network are equipped with a transceiver that can operate in one of two modes: transmission or reception. Nodes cannot simultaneously transmit and receive. Channel sensing: The receiver node is able to detect the presence of a carrier signal and measure its power even for messages that cannot be decoded into a valid packet. Collisions: In the case of simultaneous transmissions in the system, neither of the packets can be received unless one of the transmissions captures the receiver. The receiver can be captured if the power level of one of the transmissions is significantly larger than the power level of all other simultaneous transmissions. Such a capturing mechanism is the driving factor of the advantages gained through channel reuse. Channel coordinators: The channel resources are managed and distributed by channel coordinators. These coordinators can be ordinary nodes that are selected to perform the duty, or they can be specialized nodes. The channel is provided to the nodes in the network for their transmission needs by these channel coordinators. The system is also assumed to be a closed system where all the nodes comply with the channel access rules. DCA-TRACE includes two additional mechanisms on top of MH-TRACE: (i) a mechanism to keep track of the interference level from the other CHs in each frame (ii) a mechanism to sense the interference level from the transmitting nodes in each data slot in each frame. The MH-TRACE structure provides CHs the ability to measure the interference from other CHs in their own frame and in other frames through listening to the medium in the CA slot of their own frame and the Beacon slots of other frames. Cooperative load balancing in MANET Cooperative load balancing is a situation in communication networks in which too many packets are present in a part of the subnet. A cooperative load balancing leads to packet losses and bandwidth degradation and waste time and energy on cooperative load balancing. When cooperative load balancing occurs, it is normally concentrated on a single router, whereas due to the shared medium of the MANET, cooperative load balancing will not overload the mobile nodes but has an effect on the entire coverage area. Cooperative load balancing control is the main problem in ad-hoc networks. Cooperative load balancing control is associated with controlling traffic incoming in a telecommunication network. To avoid congestive crumple or link capabilities of the intermediate nodes and networks and to reduce the rate of sending packet cooperative load balancing control are used extensively. Cooperative load balancing control and dependability mechanisms are combined with Transports Control Protocol (TCP) to perform the cooperative load balancing control without explicit feedback. MH-TRACE In MH-TRACE, certain nodes assume the roles of channel coordinators, here called cluster-heads. All CHs send out periodic Beacon packets to announce their presence to the nodes in their neighborhood. When a node does not receive a Beacon packet from any CH for a predefined amount of time, it assumes the role of a CH. This scheme ensures the existence of at least one CH around every node in the network. In MH- TRACE, time is divided into super frames of equal length where the super frame is repeated in time and further divided into frames. Each cluster head operates using one of the frames in the super frame structure and provides channel access for the nodes in its communication range. Each frame in the super frame is further divided into sub frames. The control sub-frame is used for signaling between nodes and the CH, and the data sub-frame is used to transmit the data payload. In the Beacon slot, CHs announce their existence and the number of available data slots in the current frame. The CA slot is used for interference estimation for CHs operating in the same frame (co-frame CHs). During the CA slot, CHs transmit a message with a given probability and listen to the medium to calculate interference caused by other CHs operating in the same frame. There are an equal number of IS slots and data slots in the remainder of the frame. During the IS slots, nodes send short packets summarizing the information that they are going to be sending in the corresponding data slot. By listening to the relatively shorter IS packets, receiver nodes become aware of the data that are going to be sent and may choose to sleep during the corresponding data slots. These slots contribute to the energy savings mechanism by letting nodes sleep during the relatively longer data slots whose corresponding IS packets cannot be decoded IS packets can also carry routing information. Dynamic Channel Allocation for TRACE In MH-TRACE, each CH operates in one of the frames in the Super frame. Since the number of data slots is fixed, the CH can only provide channel access to a limited number of nodes. Due to the dynamic structure of MANETs, one CH may be overloaded while others may not be using their data slots. In that case, although there are unused data slots in the super frame, the overloaded CH would provide channel access only to a limited number of nodes, which is equal to the number of

4 data slots per frame, and the CH would deny the channel access requests of the others. Thus, the system needs a dynamic channel allocation scheme to provide access to a larger number of nodes. In MH- TRACE, CHs use this mechanism to choose the minimum interference frame for themselves. DCATRACE makes use of the same structure. However, in order to accommodate temporary changes in the interference levels that may occur due to CH resignation or unexpected packet drops, an exponential moving average update mechanism is used to determine the current interference levels in each frame. Where I k,t and I k,t-1 are the interference levels of the k th slot in the current and the previous super frame, respectively. M k,t is the measured interference level of the k th slot in the current super frame, and a is a smoothing factor, which is set to 0:2 in our simulations. The interference level of the frame is taken as the maximum interference level among the interference levels of the Beacon and CA slots. Medium Access Control protocols MAC protocols for wireless networks can be classified as coordinated and uncoordinated MAC protocols based on the collaboration level. In uncoordinated protocols such as IEEE , nodes contend with each other to share the common channel. For low network loads, these protocols are bandwidth efficient due to the lack of overhead. However, as the network load increases, their bandwidth efficiency decreases. Also, due to idle listening, these protocols are in general not energy efficient. On the other hand, in coordinated MAC protocols the channel access is regulated. Fixed or dynamically chosen channel controllers determine how the channel is shared and accessed. Effective MAC protocol design is the maximization of spatial reuse and providing support for non-uniform load distributions as well as supporting multicasting at the link layer. Multicasting allows sending a single packet to multiple recipients. Collaborative Load Balancing for TRACE In the TRACE protocols, nodes contend for channel access from one of the CHs that have available data slots around themselves. After successful contention, they do not monitor the available data slots of the CHs around them. Due to the dynamic nature of the network load, a cluster with lots of available data slots may become heavily loaded during a data stream. In order to tackle this issue, nodes should consider the load of the CH not only when they are first contending for channel access but also after securing a reserved data slot during the entire duration of their data stream. In order to further elaborate nodes are source nodes and need to contend for data slots from one of the CHs. Each CH has six available data slots. In MH-TRACE, if their contentions go through in alphabetical order, node G would mark CH1 as full and would ask for channel access from CH2. However, if node G secures a data slot from CH1 before any of the nodes, one of the source nodes would not be able to access to the channel. In DCA-TRACE, once CH1 allocates all of its available slots, it triggers the algorithm to select an additional frame. However, accessing one additional frame might not always be possible, if the interference levels on all the other frames are too high. Moreover, accessing additional frames increases the interference in the Beacon and Header slots of these frames and may trigger CH resignations and reselections in the rest of the network that temporarily disturbs ongoing data streams on the resigned CHs. Finally, accessing additional frames increases interference on the IS and data slots of the new frame and decreases the potential extent these packets can reach. In order to overcome these difficulties, Propose CMH-TRACE and CDCA-TRACE, which add cooperative CH monitoring and reselection on top of MH-TRACE and DCA-TRACE, respectively. In CMH-TRACE and CDCATRACE, nodes continuously monitor the available data slots at the CHs around themselves announced by the Beacon messages. When all the available data slots for a CH are allocated, with a probability p, the active nodes attempt to trigger the cooperative load balancing algorithm. Supporting multicasting services at the link layer is essential for the efficient use of the network resources, since this approach eliminates the need for multiple transmissions of an identical payload while sending it to different destinations. The traffic load may be highly non-uniform over the network area. Thus, it is crucial that the MAC protocol be able to efficiently handle spatially non-uniform traffic loads. Uncoordinated protocols intrinsically incorporate spatial reuse and adapt to the changes in load distribution through the carrier sensing mechanism.

5 When the cooperative load balancing is triggered, the node that is currently using a data slot from the heavily loaded CH contends for data slots from other nearby CHs while keeping and using its reserved data slot until it secures a new data slot from another CH. Algorithm The cooperative load balancing algorithm assumes that an adequate description of a system is given by a finite number of states. Each state is assigned a probability of the system being in that state. The typical movement of the stock market could be considered as a simple two-state model in terms of up and down movement of the index. Cooperative load balancing algorithm approximation for fading channels dates back to the early work of Gilbert who built a two-state cooperative load balancing algorithm known as the Gilbert-Elliott channel. In a simplified Gilbert model, the error probabilities in bad and good states are 1 and 0, respectively. Assuming 1 and 0 denote successful and erroneous transmission in a given slot, the state transition. The Normal state represents a perfect channel in which there is no error present (i.e., probability of error is zero), whereas the Lossy state represents a wireless channel in which no packet can be delivered without error (i.e., probability of error is one). The channel statistics are controlled by a set of transition probabilities that determine the individual probabilities P(N) and P(L). The data rate of discrete finite random variables (X 1,X 2,,,,, X N ) is defined as: H 0 = lim N H (X 1,X 2,,,,, X N ) / N If the random variables are stationary, we have lim N H (X 1,X 2,,,,, X N ) / N = N H(X N X1,,,,,X N-1 ); and in case of stationary load balancing sequence we have H 0 = lim N H (X N X N-1 ) = H ( X 2 X 1 ) For a stationary load balancing sequence, the net probability flow between the two states is zero once the stationary distribution has been reached. In our case we have four equations, Equations (1)-(4) with six unknowns, and therefore, it is possible to assign the desired stationary probabilities to both states {P(N); P(L)} and calculate the transition probabilities {P(N L); P(L N)} accordingly. Using the two state model, one can generate a simulated wireless channel behavior for the protocol under study and perform realistic simulations. In the state transition behavior of the Gilbert model is illustrated. The channel spends some percentage of the total simulation time, determined by in the normal state and some time determined by in the Lossy state. Moreover, errors occur in bursts due to the fact that the channel spends portions of time in both states. When the channel is in the Lossy state, errors are introduced according to the length of the packet, the probability of error for a longer packet is higher than the probability of error for a shorter packet. It is more likely for a data packet to be in error than for a beacon packet, which is the shortest packet in TRACE, to be in error. TRACE method helps us to provide a stationary load balance on the network. The load can be calculated using the above formula to provide a load balance across the network. Implementation Using Network Simulator NS is a public domain simulator boasting a rich set of Internet Protocols, including terrestrial, wireless and satellite networks. NS is the most popular choice of simulator used in research papers. NS is constantly maintained and updated by its large user base and a small group of developers at ISI. NS is a discrete event simulator targeted at networking research. It provides substantial support for simulation of TCP, routing, and multicast protocols over wired and wireless networks. It includes an optional network animator (NAM). The Network Animator (NAM) NS together with its companion, NAM, form a very powerful set of tools for teaching networking concepts. NS contains all the IP protocols typically covered in undergraduate and most graduate courses, and many experimental protocols contributed by its ever-expanding users base. However, coordinated protocols require careful design at the MAC layer, allowing the channel controllers to utilize spatial reuse and adapt to any changes in the traffic distribution. Similar to cellular systems, coordinated MANET MAC protocols need specialized spatial reuse and channel borrowing mechanisms that address the unique characteristics of MANETs in order to provide as high bandwidth efficiency as their uncoordinated counterparts.

6 With NAM, these protocols can visualize as animations. and hybrid channel allocation (HCA), which combines the two former methods. In a fixed channel allocation scheme, the same numbers of channels are permanently allocated to the radios at the base stations. To study fixed channel allocation, most authors used graph coloring / labeling techniques. The FCA method performs very well under a high traffic load, but it cannot adapt to changing traffic conditions or user distributions. To overcome the inflexibility of FCA, many authors propose dynamic channel allocation (DCA) methods. In contrast to FCA, there is no constant relationship between the base stations in a cell and their respective channels. All channels are available for each base station and they are assigned dynamically as new users arrive. Typically, the available channels are evaluated according to a cost function and the one with the minimum cost is used. V. CONCLUSION Figure 3.2 Window Of A Network Animator(NAM) Due to node mobility and the dynamic nature of the sources in a MANET, the network load oftentimes is not uniformly distributed. A flexible and cost-efficient method for establishing communication between different parties and each wireless network operates in a frequency band assigned by the authorities that regulate the frequency spectrum in a given country. In general, the communication medium assigned to a given network is shared among the communication devices using some multiple access technique. Frequency Division Multiple Access (FDMA) is one of the widely used techniques that enables several users to share a communication medium that consists of a given frequency band. The basic principle of FDMA is to split up the available bandwidth to distinct subbands called channels. Assigning the radio transceivers to these channels is commonly referred to as the channel allocation problem. An efficient channel allocation is a cornerstone of the design of wireless networks. We derive the Nash equilibrium to show that they result in load balancing over the channels. Our main results show that there exist two types of Nash equilibrium: in the first type, each user distributes his radios over the available channels, whereas in the second type, some users allocate multiple radios on certain channels. We show that a Nash equilibrium that resists coalitions of users is necessarily fair as well. Furthermore, we propose three algorithms to achieve the Nash equilibrium. The first is a sequential algorithm that needs global coordination, the second is a distributed algorithm that needs perfect information and the third is a distributed algorithm that is based on imperfect information. A significant amount of work on channel allocation in wireless networks, notably for cellular networks and channel allocation schemes in cellular networks can be divided into three categories: fixed channel allocation (FCA), dynamic channel allocation (DCA) A light weight dynamic channel allocation algorithm and a cooperative load balancing algorithm the dynamic channel allocation works through carrier sensing and does not increase the overhead. It has been shown to be very effective in increasing the service levels as well as the throughput in the system with minimal effect on energy consumption and packet delay variation. The cooperative load balancing algorithm has less impact on the performance compared to the dynamic channel allocation algorithm. Both of the algorithms as well as the combined system also have a fast response time, which is on the order of super frame duration of 100 ms, allowing the system to adjust under changing system load. There are many additional challenges in real life implementation of all protocols. In addition to synchronization, imperfect physical layers, and interference from devices out of the system, limited memory and computing capabilities of the hardware are among the challenges to be tackled. In order to test the feasibility of the TRACE protocol in real life scenarios that have these additional challenges, we recently implemented TRACE on NS2 software defined radio systems communicating on the 914e+6 freq ISM band. In our implementation, we successfully used a synchronization algorithm that does not rely on a GPS system and instead uses existing Beacon, Contention and IS packets. We tested the TRACE system with 4 platforms positioned in multi-hop, multi-cluster formation. Our preliminary results show that the algorithm achieves a synchronization accuracy of 100 ms in this environment. We observed that the TRACE protocol maintains its stability with this accuracy level and successfully runs an application providing real time voice communication.

7 REFERENCES [1].B. Tavli, and W. B. Heinzelman, MH-TRACE: Multi hop time reservation using adaptive control for energy efficiency, IEEE J. Sel. Areas Commun., vol. 22, no. 5, pp , Jun [2].J. Xie, A. Das, S. Nandi, and A. Gupta, Improving the reliability of ieee broadcast scheme for multicasting in mobile adhoc networks, in Proc. IEEE Wireless Commun. Netw. Conf., 2005, vol. 1, pp [3].N. Jain, S. Das, and A. Nasipuri, A multichannel CSMA mac protocol with receiver-based channel selection for multihop wireless networks, in Proc. 10th Int. Conf. Comput. Commun. Netw., 2001, pp [4].F. Tobagi, and L. Kleinrock, Packet switching in radio channels: Part II the hidden terminal problem in carrier sense multipleaccess and the busy-tone solution, IEEE Trans. Commun., vol. 23, no. 12, pp , Dec [5].M. Felegyhazi, M. Cagalj, S. Bidokhti, and J.P. Hubaux, Noncooperative multi-radio channel allocation in wireless networks, in Proc. IEEE 26th Conf. Comput. Commun., May. 2007, pp [6].C.L. I, and P.H. Chao, Distributed dynamic channel allocation algorithms with adjacent channel constraints, in Proc. 5th IEEE Int. Symp. Personal, Indoor Mobile Radio Commun., Wireless Network Catching Mobile Future, Sep. 1994, vol. 1, pp