Ad hoc network is a combination of mobile communication and computer network. The information exchange of the network adopts the packet switching mechanism in the computer network. The user terminal is a portable mobile terminal. Each user terminal in ad hoc networks works as both router and host.
Mobile ad hoc network can make use of the routing and forwarding function of mobile terminals to communicate without infrastructure, thus making up for the defects of no network communication infrastructure. Ad hoc network technology provides a solution for computer supported cooperative work system, but just as everything has its two sides, ad hoc network also has its advantages and limitations. Although ad hoc network technology provides a solution for computer supported cooperative work system, as the saying goes, "Every coin has its two sides.", ad hoc network is no exception.
1. Dynamic change of network topology
In mobile ad hoc network, due to the random movement of user terminals, the on-off and on-time switching of nodes, the change of transmission power of wireless transmitting devices, the mutual interference between wireless channels and the influence of terrain, the network topology formed by wireless channels between mobile terminals may change at any time, and the change mode and speed are unpredictable.
2. No-center network
Mobile ad hoc network has no strict control center, and all nodes are equal. It is a kind of peer-to-peer network. Nodes can join and leave the network at any time, and the failure of any node will not affect the operation of the whole network, which has a strong resistance to damage.
3. Multi-hop network
Due to the limited transmission power and coverage of the mobile terminal, when the terminal wants to communicate with the terminal beyond the coverage, it needs to use the intermediate node for forwarding.
It is noteworthy that unlike the multi hop routing in the general network, the multi hop routing in the wireless ad hoc network is completed by the collaboration of common nodes instead of by the special routing equipment.
4. Limited wireless transmission bandwidth
The physical characteristics of wireless channel determine that the bandwidth of mobile ad-hoc network is much lower than that of wired channel, and the collision, signal attenuation, noise interference and channel interference caused by competing shared wireless channel make the actual bandwidth of mobile terminal far less than the theoretical value.
5. Limitations of mobile terminals
Mobile terminals in ad hoc network (such as laptops, mobile phones, etc.) have the advantages of dexterity, portability and good mobility, but at the same time, their limited power supply, small memory, low CPU performance and other limitations make us need to consider these factors when developing applications.
(Translated from Baidu Baike APP)