Ad hoc technology becomes a new hotspot in wireless communication

China's routing technology is still developing very rapidly, and new technologies are constantly emerging. Ad hoc technology is one of them and has gradually become a hot topic in wireless communication. Adhoc technology research started in 1970s. In the United States, DARPA began to study the application of the packet wireless network PRNET: PacketRadioNetwork in the battlefield environment for military purposes.

Unlike traditional wireless networks, Ad hoc technology networks neither require a fixed network structure nor a dedicated fixed base station or router as the Management Center of the network. Each node in the network has a vro function. It can discover and maintain routes to other nodes, and send and forward data packets to neighbor nodes. Due to its simple and flexible networking, low cost, and strong viability, the application scope is expanding from the first military to emergency communication scenarios such as earthquakes and fires. As one of the important features of the B3G system, Ad hoc technology is becoming a hot topic of research. This article studies the networking methods that Adhoc technology may adopt in future wireless communication, and analyzes the advantages and disadvantages of various methods.

Adhoc independent networking

Independent networking means that nodes in the same network communicate with each other, instead of connecting to any network with infrastructure. An independent Adhoc Network can be divided into two types: A large Adhoc independent network and a small Adhoc independent network.

Large-scale independent Adhoc Network

A large-scale independent Adhoc Network contains hundreds of nodes. Some researchers have suggested using a large-scale Adhoc Network to form a wireless MAN or even a wide area network to replace existing wired communication networks. At present, it seems that this idea is not practical and lacks potential commercial value. It can only be used as a solution for scientific research. Because Adhoc is suitable for transmitting very important information with a very small amount of data in certain scenarios, such as sending commands on the battlefield and notifying other vehicles about traffic jams on highways. Large-scale Ad hoc technology networks are not suitable for transmitting large amounts of information, because large-scale Ad hoc technology networks pose high risks, high costs, and low efficiency.

1) security issues

Wireless channels are exposed to external environments, which are prone to theft and interference and attacks such as active intrusion, forged identities, and denial of service attacks. In addition, non-central and non-organizational network structures are also vulnerable to attacks. Since there is no infrastructure for centralized control, it is very difficult to use a key distribution center or a trusted Certificate Authority to provide key and digital certificate help nodes for mutual authentication.

In the field of secure routing, the most important thing in future research is to track and eliminate behavior failure nodes. Tracking and eliminating some invalid nodes of these existing routes can prevent network isolation problems. These problems are very important in wireless Adhoc networks without central control functions. Because individual nodes in the wireless Adhoc Network Act as routers and forward information packets within their wireless coverage. If a node is damaged or fails, the route passing through the node will be threatened. In this way, a mechanism is required to save the route when the node fails or crashes. Nodes in a wireless Adhoc Network are moved. If a node is a component of some invalid routes, network isolation will occur: A part of the network cannot communicate with another part. In large-scale Ad hoc technology networks, it is difficult to find a perfect security mechanism to meet the above requirements.

2) High routing costs

As the network scale expands, the cost of Signaling will increase dramatically. In the draft IETF routing protocol, such as the passive routing protocols such as ovv and DSR, the source node needs a flood route request to find the route of the target node. In a large-scale Adhoc Network, such requests consume a large amount of network resources.

3) Changes in Transmission Performance

In addition to security and Routing Problems, Adhoc Network Performance indicators such as latency and throughput will also drop sharply as the number of hops increases.