Opportunity-based network coding (COPE) studies the specific implementation of network coding at the protocol level in a wireless environment, but COPE passively waits for the emergence of coding opportunities. In order to improve the performance of the network coding to a greater extent, it is necessary to combine the network coding with the wireless routing protocol to create more coding opportunities on the wireless node to reduce the total number of transmissions and effectively increase the throughput of the network. Current coding-aware routing algorithms mainly include routing protocols based on Markovian routing metrics, coding-aware opportunistic routing protocol (CORE), distributed coding-aware routing protocol (DCAR), rate-matching coding-aware multipath routing protocol (RCR), and coding-aware Multi-path routing protocol (CAMP), etc. New routing metrics and cross-layer design issues in the field of code-aware routing in wireless networks need further study.
Network coding (NC) enables network nodes to implement both routing and coding functions. It has been proven to be an effective method that can approach the theoretical transmission limit of network capacity. In 2000, R. Ahlswede and others published an article "Network informaTION flow" which proved that the multicast network can reach the theoretical upper limit of the maximum flow capacity under the network coding transmission mode. The network coding has just been put forward for several years, and the research work mainly focuses on the theory, construction and application of network coding. Since 2005, many foreign scholars have begun to study network coding in wireless networks. However, the research and application of network coding in wireless networks (including wireless self-organizing networks, wireless mesh networks, and wireless sensor networks) is still in its infancy.
The theory and application of network coding in wireless networks and wired networks are significantly different, which is mainly determined by the structural characteristics of wireless networks. At the same time, the wireless network environment is also a very suitable application field for network coding. Because the unreliability of the wireless link and the broadcast characteristics of the physical layer are very suitable for using the coding method. Compared with the traditional network coding mechanism, the network coding in the wireless network can especially increase the throughput of the unicast stream, which is also one of the main differences between the network coding in the wireless network and the traditional network coding, which also benefits from the wireless medium Broadcast characteristics. Figure 1 shows an example of three nodes using a network code to communicate in a wireless network: Node A and Node B communicate information p1 and p2 with each other. The arrows in Figure 1 represent wireless links. Figure 1 (a) uses traditional wireless communication, which requires 4 transmissions to complete the exchange of messages. However, if the broadcast characteristics of the wireless medium are used and p1 and p2 are directly XORed and forwarded out, then at node B, p1 can be recovered according to the received information; in the same way, at node A can also be recovered Information p2 comes. Therefore, after using the network coding technology (see Figure 1 (b)), only three transmissions are needed to achieve all the communication requirements of the traditional method.
Based on the above ideas, KatTI et al. Proposed an opportunity-based network coding method (COPE). COPE is the first study of the specific implementation of network coding at the protocol level in a wireless environment. The COPE protocol uses opportunity monitoring and receiving reports to obtain message information stored by neighbor nodes. After obtaining the message information stored by all neighboring nodes, each node independently uses local information to determine which data packets need to be encoded and how to encode, in order to maximize the number of messages that can be sent in one transmission. Through COPE, the throughput of the wireless network can be effectively improved.
We design and manufacture Electric Linear Actuators For Vehicles, Linear Actuators For Vehicles, Electric Actuators For Vehicles, Electric Motors For Vehicles , etc.
Linear Actuator , linear electric actuator-with heavy load capability and high speed design, These Electric Linear Actuator can be applied to various kinds of industrial transmission solutions, such as excavator,mechanical arm and Vehicles etc, without worrying the harsh working environment, ball and Acme screw threaded spindle is available for user to choose.
Actuators For Vehicles Industry
Electric Linear Actuators For Vehicles, Linear Actuators For Vehicles, Electric Actuators For Vehicles,Electric Motors For Vehicles
TOMUU (DONGGUAN) ACTUATOR TECHNOLOGY CO., LTD. , http://www.tomuu.com