Switch type multicast transmission method

Abstract

A switchable multicast transmission method belongs to a multiple-broadcast transmission method in the radio data communication system. The aim of the invention is to fully use the advantages of high multicast throughput rate based on the network coding, higher multicast throughput rate based on the random linear coding (digital fountain code), low feedback spending and strong flexibility and the predominance that the time delay of the multicast based on ARQ is smaller when the service speed is lower, to construct a multicast plan that the better throughput and time delay are realized when the switching is executed based on the scene parameter. The invention sets a number threshold L, a speed threshold T and a difference threshold M as the main determination criterions for switching the three transmission modes. Different multicast transmission strategies are respectively used according to the difference of three groups of parameters of service arrival speed, the quality state of channel corresponding with each receiver and the number of the receivers. According to the invention through setting parameter and switching plan, various transmission plans can transmit data at the most appropriate environment. The transmission performance of the multicast system is optimized and the transmission efficiency is increased.

Description

technical field [0001] The invention belongs to a multicast transmission method in a wireless data communication system, in particular to a switching multicast transmission method. Background technique [0002] Wireless communication and wireless network have developed rapidly in the past 10 to 20 years. Compared with wired communication, wireless communication has disadvantages such as time-varying channels, susceptibility to interference, and limited power and spectrum. However, the open transmission medium of wireless communication Features can also be transformed into advantages in some occasions, such as multicast or broadcast situations—that is, multiple (or all) receivers need to obtain common information at the same time. transmission bandwidth. [0003] Due to the harsh environment of wireless communication, the traditional multicast scheme is often based on ARQ (Automatic Repeat Request) to ensure that the information is received correctly. The general flow of the...

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Problems solved by technology

However, for services with bursty characteristics and low average arrival rate, the digital fountain code needs to wait until the number of data packets in the buffer reaches a certain number before encoding and transmission, so its waiting delay may affect the delay performance of the entire system. to adversely affect

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