For Push-To-Talk (PTT) system based on Public Mobile Data Network (PMDN), the end-to-end time delay is the key aspect of the user's experience. The Push-Over-Cellular (POC) scheme defined by Open Mobile Alliance (...For Push-To-Talk (PTT) system based on Public Mobile Data Network (PMDN), the end-to-end time delay is the key aspect of the user's experience. The Push-Over-Cellular (POC) scheme defined by Open Mobile Alliance (OMA) is based on the VoIP phone model and use SIP protocol as the call control scheme. The call setup time delay in SIP may reach to several seconds, which is unac-ceptable for the PTT service. In this paper, we provide a new call control scheme for PTT system based on PLMN network. By combining the apriority knowledge of PTT call model and the priority control scheme, we encapsulate the signaling message and the voice data into a same data packet, when the user push the button, the voice and the call control signaling are sent to the server at the same time. So the long time delay of call setup procedure of POC scheme can be eliminate. The end-to-end call delay can be decreased significantly. The experiment result based on the commercial CDMA2000 1X network of China Unicom shows that the call delay can be decreased to 600 ms, which approach to the traditional trunk communication system's requirement.展开更多
GPRS承载的Push to Talk
Push to talk(PTT)难以通过GSM蜂窝网实现,由于GSM电路交换的本质使得PTT严重地浪费了蜂窝网的无线资源和网络资源,令运营商看不到业务的盈利前景.在GPRS技术出现之后,通过IETF和3GPP的有关协议实现PTT成为可能...GPRS承载的Push to Talk
Push to talk(PTT)难以通过GSM蜂窝网实现,由于GSM电路交换的本质使得PTT严重地浪费了蜂窝网的无线资源和网络资源,令运营商看不到业务的盈利前景.在GPRS技术出现之后,通过IETF和3GPP的有关协议实现PTT成为可能.原因在于,PTT话音呼叫是一种半双工业务,几乎是即时发起的,无线资源和传输资源只在会话持续时期被占用,如图1所示:展开更多
NOKIA 6170近日上市，这是一款不锈钢材质的翻盖手机，可谓是时尚三边手机的代表。此款手机主要特点是VGA照相功能，64K彩色液晶显示内屏，支持所有图像视频功能及XHTML浏览，还有“即按即说”（push-to-talk）的功能，并且拥有长达11...NOKIA 6170近日上市，这是一款不锈钢材质的翻盖手机，可谓是时尚三边手机的代表。此款手机主要特点是VGA照相功能，64K彩色液晶显示内屏，支持所有图像视频功能及XHTML浏览，还有“即按即说”（push-to-talk）的功能，并且拥有长达11天的待机时间和4小时通话时间，外观是尽炫目之能事，立体与动感的完美搭配，让人动心。展开更多
文摘For Push-To-Talk (PTT) system based on Public Mobile Data Network (PMDN), the end-to-end time delay is the key aspect of the user's experience. The Push-Over-Cellular (POC) scheme defined by Open Mobile Alliance (OMA) is based on the VoIP phone model and use SIP protocol as the call control scheme. The call setup time delay in SIP may reach to several seconds, which is unac-ceptable for the PTT service. In this paper, we provide a new call control scheme for PTT system based on PLMN network. By combining the apriority knowledge of PTT call model and the priority control scheme, we encapsulate the signaling message and the voice data into a same data packet, when the user push the button, the voice and the call control signaling are sent to the server at the same time. So the long time delay of call setup procedure of POC scheme can be eliminate. The end-to-end call delay can be decreased significantly. The experiment result based on the commercial CDMA2000 1X network of China Unicom shows that the call delay can be decreased to 600 ms, which approach to the traditional trunk communication system's requirement.
文摘GPRS承载的Push to Talk
Push to talk(PTT)难以通过GSM蜂窝网实现,由于GSM电路交换的本质使得PTT严重地浪费了蜂窝网的无线资源和网络资源,令运营商看不到业务的盈利前景.在GPRS技术出现之后,通过IETF和3GPP的有关协议实现PTT成为可能.原因在于,PTT话音呼叫是一种半双工业务,几乎是即时发起的,无线资源和传输资源只在会话持续时期被占用,如图1所示:
