Research On Key Technology Of Instant Messaging For Mobile Platform

With the rapid developm ent of s mart devices and the rise of m obile Internet,the development of mobile applications has become popular.Instant messaging system has achieved great success withmobile development boom and people relying on the mobile phone.However,these instant messaging systems are not reliable in the mobile wireless network.This paper will provide optimization proposal to im prove the reliability of transmission by researching the key technology of instant message.Considering the data co mmunication of the mobile platform is more dependent on push technology,this paper com pares the current push technologies,XMPP protocol is not only an ideal m essage push technology in the m obile platform,but also the standard protocol for instant m essaging,and finally we choose it as the key protocol for our study of mobile IM system.After the introduction of the message transmission process and the calculation m odel of trans mission delay,we consider the basic message packet from the XMPP protocol and propose using JSON to reduce the data redundancy caused by XML.The im plementation of this schem e isbased on the message types transmitted by the protocol.For the message queue of the text type with high delay,it is transmitted in only one m essage packet.For a message of voice,it will be com pressed after Base64 encodi ng.In order to cont rol a single m essage stanzas size,in m any cases such as voi ce data,we use segm ented transmission mode.Considering the packet lose in m essage transmission,we put for ward message receipt mechanism.In the sam e time,we give the solu tion of timeout message retransmission,in order to im prove the relia bility of data tran smission.At last,we propose a non-negotiation m echanism for the transmission out-of-band,which can reduce the load pres sure caused by the tr ansmission of large files and implement function of the of fline files after comparing the negotiation m echanism for t he transmission in-band.After studying the key technolog ies,this paper will realize the in stant messaging client in Android system.After analyz ing the basic needs,the design of each functional module is done in detail.The realization of the system is based on the open source framework asmack as the m ain body of the XMPP protocol.After the completion of the system,we analysis the te st result of the cost of transm ission,the rationality of retransmission time and the compression of the voice.