Wireless ad hoc network
The primary challenge in building a MANET is equipping each device to continuously maintain the information required to properly route traffic.
[7] Problems with packet radios are: (1) bulky elements, (2) slow data rate, (3) unable to maintain links if mobility is high.
Many academic papers evaluate protocols and their abilities, assuming varying degrees of mobility within a bounded space, usually with all nodes within a few hops of each other.
In the early 1990s, Charles Perkins from SUN Microsystems USA, and Chai Keong Toh from Cambridge University separately started to work on a different Internet, that of a wireless ad hoc network.
ABR was implemented successfully into Linux OS on Lucent WaveLAN 802.11a enabled laptops and a practical ad hoc mobile network was therefore proven[3][10][11] to be possible in 1999.
[citation needed] Minimal configuration and quick deployment make ad hoc networks suitable for emergency situations like natural disasters or military conflicts.
The presence of dynamic and adaptive routing protocols enables ad hoc networks to be formed quickly.
Apple's iPhone with iOS version 7.0 and higher is capable of multi-peer ad hoc mesh networking.
A wireless ad hoc network does not have fixed topology, and its connectivity among nodes is totally dependent on the behavior of the devices, their mobility patterns, distance with each other, etc.
[25][26][27] Ad hoc mobile communications come in well to fulfill this need, especially its infrastructureless nature, fast deployment and operation.
Flying ad hoc networks (FANETs) are composed of unmanned aerial vehicles, allowing great mobility and providing connectivity to remote areas.
[29] UAVs have also been used by US Air Force[30] for data collection and situation sensing, without risking the pilot in a foreign unfriendly environment.
[31] Some defense companies (such as Rockwell Collins, Silvus Technologies and Rohde & Schwartz) have produced products that enhance ship-to-ship and ship-to-shore communications.
Especially at times of earthquakes when radio towers had collapsed or were destroyed, wireless ad hoc networks can be formed independently.
[31][36] Wireless ad hoc networks allow sensors, videos, instruments, and other devices to be deployed and interconnected wirelessly for clinic and hospital patient monitoring, doctor and nurses alert notification, and also making senses of such data quickly at fusion points, so that lives can be saved.
[39] A key characteristic of such applications is that nearby sensor nodes monitoring an environmental feature typically register similar values.
[41][42] Several books[43][1] and works have revealed the technical and research challenges[44][45] facing wireless ad hoc networks or MANETs.
The advantages for users, the technical difficulties in implementation, and the side effect on radio spectrum pollution can be briefly summarized below: The obvious appeal of MANETs is that the network is decentralised and nodes/devices are mobile, that is to say there is no fixed infrastructure which provides the possibility for numerous applications in different areas such as environmental monitoring, disaster relief and military communications.
Since the early 2000s, interest in MANETs has greatly increased which, in part, is due to the fact mobility can improve network capacity, shown by Grossglauser and Tse along with the introduction of new technologies.
For example, in the cellular network setting, a drop in coverage occurs if a base station stops working, however the chance of a single point of failure in a MANET is reduced significantly since the data can take multiple paths.
[54] Circa 2020, the general consensus finds the 'best' modulation for moving information over higher frequency waves to be orthogonal frequency-division multiplexing, as used in 4G LTE, 5G, and Wi-Fi.
[55] Such software updating relied on epidemic mode of dissemination of information and had to be done both efficiently (few network transmissions) and fast.
Flooding is used in bridging and in systems such as Usenet and peer-to-peer file sharing and as part of some routing protocols, including OSPF, DVMRP, and those used in wireless ad hoc networks.
One key problem in wireless ad hoc networks is foreseeing the variety of possible situations that can occur.
As a result, modeling and simulation (M&S) using extensive parameter sweeping and what-if analysis becomes an extremely important paradigm for use in ad hoc networks.
The testbed was based on a version of the "MANE" (Mobile Ad hoc Network Emulator) software originally developed by NRL.
Early work included simulating ad hoc mobile networks on sparse and densely connected topologies.
[66] To thwart or prevent such attacks, it was necessary to employ authentication mechanisms that ensure that only authorized nodes can inject traffic into the network.
Trust establishment and management in MANETs face challenges due to resource constraints and the complex interdependency of networks.
Managing trust in a MANET needs to consider the interactions between the composite cognitive, social, information and communication networks, and take into account the resource constraints (e.g., computing power, energy, bandwidth, time), and dynamics (e.g., topology changes, node mobility, node failure, propagation channel conditions).
