Location Service Protocols Research Articles

Balance the Energy Consumption of Geographic Hashing Location Service in Wireless Sensor and Actor Networks

Location service is an efficient solution to handle actor mobility in wireless sensor and actor networks. Geographic hashing location service (GHLS) is a flat hashing-based protocol which has better energy efficiency than other location service protocols. Nevertheless, GHLS suffers from unbalanced energy consumption due to the fixed hashed region. In this paper, we propose a new protocol termed as GHLS-R2 to achieve load balance in two aspects: location server rotation and energy-aware geographic routing. Simulation results show that GHLS-R2 protocol can effectively balance the energy consumption, and hence prolong the network lifetime significantly.

ZGLS: a novel flat quorum-based and reliable location management protocol for VANETs

In location management services, a destination advertises its position attributes to a set of vehicles called location servers while, a source obtains these attributes from such location servers to track destination. The location management techniques in VANET have been categorized into flooding-based, flat hashing-based, hierarchical hashing-based and hierarchical quorum-based techniques. In flooding-based location service, destination information is flooded to the entire network which results into high congestion, low throughput and non-scalable network. In flat hashing, a global hash function is applied to compute location servers of each destination which results into higher delay, drop and signaling overhead in large VANETs. In hierarchical hashing, global hash function computes location servers of destination in hierarchical order. It therefore suffers from handover signaling between servers, high load on the top hierarchy and location query delay when source and destination are apart. In hierarchical quorum-based, location servers are identified cluster-wise and therefore it also suffers from the problems similar to hierarchical techniques. To overcome these problems, ZoomOut Geographic Location Service (ZGLS) protocol is proposed which introduces flat quorum-based location management service. In contrast to the aforementioned techniques, the novelty of ZGLS lies in the fact that it has shifted the location server role from hashing-based or clustering-based geographic areas to few 1-hop neighbours, called relatives. The proposed protocol creates a chain of relatives to provide positioning and tracking service. To evaluate signalling overhead, timeliness and the reliability of update and query packets, ZGLS is compared with RLSMP and HRHLS through ns-2 simulations. The results reveal that ZGLS stands out as a better choice for large-scale sparse and dense VANETs.

A Group mobility oriented History information based Light Location Service

In a large number of location service protocols, the load for long-distance periodic updates takes up a big portion in the total load. So it’s possible to effectively reduce the overall load of a protocol through the drop of update load as to further enhance the scalability of the protocol. In this paper, with the use of mobility features of groups on network nodes, it proposes to utilize the location service framework which is based on historical information together with clustering mechanism to curtail the information amount saved by single nodes in the local location database, optimizing individual node’s memory overhead and the initialized load of location service protocol. Both higher service success ratio and lower load are enabled in the massive mobile Ad Hoc network.

Location Service Protocol for Highly Mobile Ad Hoc Network

In Vehicular Ad Hoc Networks (VANETs), location service protocol is utilised to locate locations of nodes to be used by position-based routing algorithms before the start of communication between source and destination. The existing location services proposed for Mobile Ad Hoc Networks (MANET) suffer from poor scalability in VANET environments. Protocols proposed for VANET do not consider load distribution on location servers and do not consider locality awareness that affects the efficiency of the protocols. This paper proposes a Quorum-Based Location Service Protocol (QLSP) designed for urban area topology; QLSP utilises the distance to intersection centre point and speed of a node in selecting main location server. QLSP distributes multi-copies of locations tables to multi-servers of the quorum in order to increase query success rate and to reduce query latency. QLSP shows excellent performance in reducing overhead of control packets, provides low query delay, and increases query success rate. The performance of the protocol is then compared to other existing location service protocols.

Quorum-based location service protocol for vehicular ad hoc networks in urban environment

The existing location service protocols used in vehicular ad hoc network (VANET) environments suffer from poor scalability, and do not consider load distribution on location servers while the usage of unrealistic information for selecting location servers affects the efficiency of the protocols. This paper presents a vehicular quorum location service (VQLS) protocol, which is designed for an urban area topology. VQLS uses fuzzy inference engine (FIE) in selecting the most stable node to be a main location server (MLS) based on the distance of a node to intersection centre point and its speed. The server constructs a quorum group, which consists of the nominated nodes that passing through the intersection in order to distribute the load on quorum members. VQLS shows superior performance in reducing overhead of control packets, and balance the load on dense intersection vicinity. Additional achievement is low end–to–end delay for routing packets.

Energy-efficient location services for mobile ad hoc networks

Location-based routing protocols are stateless since they rely on position information in forwarding decisions. However, their efficiency depends on performance of location services which provide the position information of the desired destination node. Several location service schemes have been proposed, but the most promising among them, hierarchical hashing-based protocols, rely on intuitive design in the published solutions. In this paper, we provide full analysis of the efficiency of routing in hierarchical hashing-based protocols as a function of the placement of the routers. Based on the theoretical analysis of the gain and costs of the query and reply routing, we propose a novel location service protocol that optimizes the distance traveled by the location update and query packets and, thus, reduces the overall energy cost. These gains are further increased in the second presented protocol by the optimal location of servers that we established through analysis of geometrical relationships between nodes and location servers. Simulation results demonstrate that the proposed protocols achieve around 30–35% energy efficiency while improving or maintaining the query success rate in comparison to the previously proposed algorithms.

Sharing Mobility Strategy Improves Location Service in Wireless Sensor and Actor Networks

Location service is an efficient solution to handle actor mobility in wireless sensor and actor networks. In previous works, the information that the actor updates to location servers is its latest location. However, in most applications, the actor knows its own mobility strategy, such as its destination, trajectory and speed. If the actor can share its mobility strategy in the update packet, it will be helpful to improve the performance of location service. In this letter, we propose a mobility strategy sharing location service protocol called MLS, to show the description of mobility strategy in the update packet and its utilization for routing. The theoretical analysis and simulation results show that, sharing mobility strategy greatly reduces the update overhead and improves the scalability of MLS.

Phero-trail: a bio-inspired location service for mobile underwater sensor networks

A SEA Swarm (Sensor Equipped Aquatic Swarm) is a collection of mobile underwater sensors that moves as a group with water current and enables 4D (space and time) monitoring of local underwater events such as contaminants and intruders. For prompt alert reporting, mobile sensors routes events to mobile sinks (i.e., autonomous underwater vehicles) via geographic routing that is known to be most efficient under mobility and scarce acoustic bandwidth. In order for a packet to be routed to the destination using geographical routing, it requires to know the location of the destination. This is accomplished by having a location service that returns the location of a requested node. Our goal is to design such location service for SEA Swarm. In this paper, we analyze various design choices to realize an efficient location service in SEA Swarm scenarios. We find that conventional ad hoc network location service protocols cannot be directly used, because the entire swarm moves along water current. We prove that maintaining location information in a 2D plane is a better design choice. Given this, we propose a bio-inspired location service called a Phero-Trail location service protocol. In Phero-Trail, location information is stored in a 2D upper hull of a SEA Swarm, and a mobile sink uses its trajectory (a la a pheromone trail of ants) projected to the 2D hull to maintain location information. This enables mobile sensors to efficiently locate a mobile sink. Our results show that Phero- Trail performs better than existing approaches.

Hierarchical Location Service with Prediction in Mobile Ad-Hoc Networks

Position-based routing protocols take advantage of location information to perform a stateless and efficient routing. To enable position-based routing, a node must be able to discover the location of the messages' destination node. This task is typically accomplished by a location service. Recently, several location service protocols have been developed for ad hoc networks. In this paper we propose a novel location service called PHLS: Predictive Hierarchical Location Service. In PHLS, the entire network is partitioned into a hierarchy of smaller and smaller regions. For each node, one node in each-level region of the hierarchy is chosen as its local location server. When the network initializes or when a node attaches the network, nodes contact their local location server with their current location information (ie. position and velocity). Then, they only need to update their location server when they move away from their current region. Finally, nodes query their location servers and get the exact or predicted location of destination nodes.

A cross-layer framework for position-based routing and medium access control in heterogeneous mobile ad hoc networks

Many Mobile Ad Hoc Networks (MANETs) are composed of nodes with heterogeneous communication capabilities in terms of transmission power, data rate, battery life, reliability, etc. Heterogeneous MANETS (H-MANETs) often encounter problems in both Medium Access Control (MAC) and routing layers due to link asymmetry. But meanwhile, H-MANETs have many advantages including: scalability, robustness, and connectivity. In this paper we present a two-layer approach which spans the MAC and network layers for H-MANETs to minimize the problems caused by link asymmetry and exploit the advantages of H-MANETs simultaneously. At the network layer, we design a hierarchical Location service (LS) protocol and a node density adaptive position-based routing protocol. At the MAC layer we propose a new MAC protocol which uses two communication channels and closely ties in with the network layer to solve the MAC problems caused by link asymmetry. We evaluate our approach using both probabilistic analysis and simulations.

Sink-oriented Dynamic Location Service Protocol for Mobile Sinks with an Energy Efficient Grid-Based Approach

Sensor nodes transmit the sensed information to the sink through wireless sensor networks (WSNs). They have limited power, computational capacities and memory. Portable wireless devices are increasing in popularity. Mechanisms that allow information to be efficiently obtained through mobile WSNs are of significant interest. However, a mobile sink introduces many challenges to data dissemination in large WSNs. For example, it is important to efficiently identify the locations of mobile sinks and disseminate information from multi-source nodes to the multi-mobile sinks. In particular, a stationary dissemination path may no longer be effective in mobile sink applications, due to sink mobility. In this paper, we propose a Sink-oriented Dynamic Location Service (SDLS) approach to handle sink mobility. In SDLS, we propose an Eight-Direction Anchor (EDA) system that acts as a location service server. EDA prevents intensive energy consumption at the border sensor nodes and thus provides energy balancing to all the sensor nodes. Then we propose a Location-based Shortest Relay (LSR) that efficiently forwards (or relays) data from a source node to a sink with minimal delay path. Our results demonstrate that SDLS not only provides an efficient and scalable location service, but also reduces the average data communication overhead in scenarios with multiple and moving sinks and sources.

Hash-Based Virtual Hierarchies for Scalable Location Service in Mobile Ad-hoc Networks

A location service is an essential prerequisite for geographic routing protocols for MANETs. We present VHLS, a new distributed location service protocol, that features a dynamic location server selection mechanism and adapts to network traffic workload, minimizing the overall location service overhead. We demonstrate that the ratio of location queries to updates is an important performance parameter in such protocols. Our analysis and simulations show that VHLS provides better query success rates, location service quality, and geographic routing performance than the GLS and GHLS protocols. VHLS also scales well as the network size and traffic workload increases.

GrLS: Group-Based Location Service in Mobile Ad Hoc Networks

In this paper, we propose a group-based location service protocol named GrLS for mobile ad hoc networks (MANETs). The novelty of GrLS is in its exploitation of group mobility to improve the efficiency of the location service. GrLS uses different location management strategies for single nodes and for groups of nodes. A single node is responsible for recruiting its own location servers and performing location update. On the other hand, in a group of nodes, only the group leader recruits the location servers and updates its location to a specific home region called group home region. Since the location update cost normally dominates the location service cost for all practical purposes, the overhead of the location service protocol is significantly reduced. Furthermore, when the nodes join or leave groups, GrLS can provide seamless location service handoff. To the best of our knowledge, GrLS is the first location service protocol in MANETs that has explored group mobility and developed group location management for mobile nodes. Both theoretical analysis and simulation results show that GrLS can achieve a higher success ratio of location query and better load balance with much lower overhead than the existing protocols without considering group mobility.

Position-based secure routing protocol in Ad Hoc network

In large and dense mobile Ad Hoc networks,position-based routing protocols can offer significant performance improvement over topology-based routing protocols by using location information to make forwarding decisions.Though many papers are about secure routing protocol in Ad Hoc now,few consider the security of the protocol based on location.The new protocol that enhanced the original Grid Location Service(GLS)protocol was proposed.To adapt to the high mobility of Ad Hoc network,SGRP completed the TESLA by adding the authentication process as new node entering networks.The simulation result shows that the new protocol can isolate the spiteful node initiating interruption at tack effectively.

A scalable quorum-based location service in ad hoc and sensor networks

Location service provides position of mobile destination to source node so that position-based routing can be applied. Previous location service protocols suffer from partial flooding overhead, and/or location failure in group movement scenarios. To overcome those deficiencies, we propose a quorum-based location service. The basic idea is that destination node registers its location along a 'column' to form an update quorum. Source node makes a query along a 'row' to form a search quorum. The destination location is detected at the intersection between the update and search quorums. The overhead of each routing task, including location service, is O(√n), where n is the number of nodes in the network. Four strategies are proposed to adjust the quorum system and improve it's performance. To guarantee the success of location retrieval, both search and update quorums are extended by face routing which traverses outer boundary of the network. The simulation results show that our proposed location service has high success rate and good scalability.

Quorum and connected dominating sets based location service in wireless ad hoc, sensor and actuator networks

Location service provides position of mobile destination to source node to enable geo-routing. In existing quorum-based location service protocols, destination node registers its location along a ‘column’ while source node makes a query along a ‘row’. Grid and quorum-based location service is based on division of network into square grids, and selecting ‘leader’ location server node in each grid. Location updates, leader reelection and information transfer are performed whenever destination and leader nodes are moving to a different grid. We propose here to apply connected dominating sets (DS) as an alternative to grids. We also improved basic quorum, and applied on DS-quorum (DS based quorum) better criterion for triggering local information exchanges and global location updates, by meeting two criteria: certain distance movement and certain number of observed link changes with (DS) nodes. Backbones created by DS nodes (using 1-hop neighborhood information) are small size, do not have a parameter like grid size, and preserve network connectivity without the help of other nodes. Location updates and destination searches are restricted to backbone nodes. Both methods use ‘hello’ messages to learn neighbors. While this suffices to construct DS, grid leader (re)election requires additional messages. Simulation results show that using DS as backbone for quorum construction is superior to using grid as backbone or no backbone at all. The proposed DS-quorum location service can achieve higher (or similar) success rate with much less communication overhead than grid-based approaches.

On the scalability of rendezvous-based location services for geographic wireless ad hoc routing

Geographic routing protocols allow stateless routing by taking advantage of the location information of mobile nodes and thus are highly scalable. A central challenge in geographic routing protocols is the design of scalable distributed location services that track mobile node locations. A number of location services have been proposed, but little is known about the relative performance of these location services. In this paper, we perform a detailed performance comparison of three rendezvous-based location services that cover a range of design choices: a quorum-based protocol (XYLS) which disseminates each node's location to O(N) nodes, a hierarchical protocol (GLS) which disseminates each node's location to O(logN) nodes, and a geographic hashing-based protocol (GHLS) which disseminates each node's location to O(1) nodes. We present a quantitative model of protocol overheads for predicting the performance tradeoffs of the protocols for static networks. We then analyze the performance impact of mobility on these location services. Finally, we compare the performance of routing protocols equipped with the three location services with two topology-based routing protocols, AODV and DSR, for a wide range of network sizes. Our study demonstrates that when practical mobile ad hoc network (MANET) sizes are considered, the constants matter more than the asymptotic costs of location service protocols. In particular, while GLS scales better asymptotically, GHLS transmits fewer control packets and delivers more data packets than GLS in MANETs of sizes considered practical today and in the near future. Additionally, in contrast to the complex GLS design, the simplicity of GHLS provides significant resilience to performance degradation from mobility. Finally, although XYLS has a comparable packet delivery ratio to GHLS, it achieves this ratio with a higher overhead.

A Novel Location-Service Protocol Based on $k$-Hop Clustering for MobileAd HocNetworks

This paper presents a novel k-hop cluster-based location service (KCLS) protocol in mobile ad hoc networks, which is able to well balance the tradeoff between the communication overheads and the accuracy of location information. Other advantages of the proposed KCLS protocol include excellent network scalability and tolerance of link breakage that can significantly reduce communication overheads and the latency caused by route path recovery. The numerical results obtained from both theoretical analysis and simulations have shown that the cost of location management using the KCLS protocol is less than 2% of the location-management cost using the link-state protocol. Especially for a large value of k, the proposed KCLS protocol is not only able to suppress the increasing rate of the total cost when the number of hosts in the network increases but also increases the hit probability of location service and reduces the passive effect of host mobility on control overhead as well. With good scalability and the capability of self-discovery, the proposed KCLS protocol is adaptable to accommodate most applications in ad hoc networks

Two scalable location service protocols for wireless ad hoc networks

We present two location service protocols, viz., the hierarchical location service protocol and the on-demand location service protocol, to track the position of mobile nodes in a wireless ad hoc network. The hierarchical location service uses a location-based hierarchy to maintain the location of nodes in the network, whereas the on-demand location service uses a unicast-based network probing, unlike flooding, to obtain the position of a node on-demand. In the unicast-based network probing, a location query for a node is unicast to nodes that are closer to a few fixed positions in the network. For a given network size, the number of such positions remains constant. Both the location service protocols use a heuristic greedy forwarding protocol, called the angular routing protocol, to circumvent dead ends, and to route packets beyond one hop. We use a theoretical framework to show that both the location service protocols are asymptotically scalable with respect to the number of nodes in the network. Further, we present results from an extensive simulation study comparing the performance of the proposed on-demand location service protocol with LAR1 and a combination of GPSR-GLS. Simulations show that the on-demand location service along with angular routing protocol outperforms the LAR1 and GPSR-GLS protocol in terms of control overhead, percentage of packets delivered, and average hop count, for various network scenarios.

Formal description and analysis of a distributed location service for mobile ad hoc networks

In this paper, we define a distributed abstract state machine (DASM) model of the network or routing layer protocol for mobile ad hoc networks. In conjunction with the chosen routing strategy, we propose a distributed logical topology based location service (LTLS) protocol and give a formal description and analysis of this protocol on the DASM model. The high dynamics of mobile ad hoc networks require routing strategies substantially different from those used in static communication networks. A strategy for such networks is geographic routing in which each network node can find its physical location via GPS or other navigation technologies. To send a packet, the sender needs to know the most recent physical location of the destination node. This location information is provided by a location service protocol. The LTLS protocol has short message delivery delay, requires small routing tables, uses relatively few administrative packets, and has very good fault tolerance properties. Our goal in defining the network layer protocol in terms of a DASM model is twofold. First, we feel that the mathematical modeling paradigm of distributed abstract state machines provides an ideal formal basis for constructing, analyzing, and validating abstract requirements specifications of mobile ad hoc network protocols. Second, we intend to utilize the resulting behavior model as a formal basis for developing executable specifications serving as a platform for experimental validation of key system attributes and exploration of alternative design choices.