Abstract: In the era of LTE mobile broadband access, operators are faced with more mobile terminal users using Internet applications to use voice services. The technical specifications of 3GPP and the corresponding technical system of the GSMA Operator Enterprise Alliance clearly define the relevant technologies for transmitting voice services in the LTE network. The voice technology based on 3GPP specifications can better reflect the social responsibility of operators and the quality of multimedia voice services. This article is based on the 3GPP technical specifications to give a technical introduction to the transmission of voice services in the LTE network, and at the same time gives suggestions for the evolution of the operator's mobile network to support LTE voice services. 1 Introduction The LTE network provides network access bandwidth greater than 100Mbps, which is comparable to and higher than the general fixed broadband access bandwidth. As in the current Internet application scenario, IP-based multimedia including voice services can be implemented end-to-end directly between users based on Internet applications; multimedia communications and voice communications based on MSN and QQ have transferred traditional telecom operators' voices Business traffic. The emergence of smart terminals has exacerbated this shift in voice traffic. The smart terminals can be installed with Google Talk or Skype software to communicate directly between user terminals. Since LTE provides higher wireless access bandwidth, the quality of end user voice calls is guaranteed; the transfer of voice traffic will be more prominent in the LTE era. In the GSM / WCDMA network, both the wireless network and the core network have CS core network elements and a dedicated wireless bearer channel TCH or CSRAB for carrying voice services. Unlike the GSM / WCDMA network technology, in the LTE / EPC network technology, the core network and the LTE wireless network only define PS bearer channel technologies with different QoS, and there is no special technology and bearer method specifically used for voice communication. How LTE-based wireless networks and terminals implement and guarantee voice services is an important issue facing operators. 2. Realization of voice service in LTE network It is expected that LTE (quasi) commercial service networks will appear in the Chinese market in 2012 or 2013. During the construction and deployment of LTE networks, based on industry development and corresponding technical specifications, the industry generally divides the implementation of LTE user terminal voice services into two types. One way is that LTE user terminals have built-in voice service software provided by Internet companies, such as built-in Google Talk or Skype, and use this software for voice communication between users; another way is to provide services to end users based on the network technology of telecom operators Voice services with better quality. The network implementation technology based on the 3GPP specifications is the network multimedia voice service implementation technology based on MMTel and the voice service technology based on the existing GSM / WCDMA network CS domain softswitch system. (1) Voice service based on OTT In LTE mobile broadband access networks, voice communication based on Google Talk and Skype software will be the choice of some LTE end users. The industry refers to the OTT (OverThe Top) method as the method of providing voice services based on the Internet. When users use voice services through LTE wireless broadband access, the quality of voice services is guaranteed based on LTE mobile broadband. Industry analysis shows that during the initial maturity period of LTE development (for example, from 2014 to 2015), about 10% of the voice services of smart terminals are realized through preset OTT voice software, that is, smart terminal users with LTE access capabilities About 10% of voice services are transferred from traditional telecommunications networks. The advantage of users using OTT to realize voice services is that the general telecommunications network adopts the network usage method of monthly traffic and no distinction between services; in addition, the user-friendly interface of voice services based on OTT is also attractive to users. At present, the OTT-based voice service communication method has become popular in high wireless access bandwidth networks such as HSPA mobile networks, especially smart terminals. It is generally believed that it is difficult for telecommunications operators to restrict users to use OTT for voice communication. Although the OTT method provides mobile terminal users with a cheap service usage price and a friendly user interface, in the early stage of LTE wireless network construction, due to construction investment and cycle reasons, it is very likely that LTE wireless coverage is discontinuous, resulting in OTT voice is dropped during the user's movement, which cannot reflect the mobile needs of terminal voice communication. Since the access network provides an indifferent transmission mode for OTT voice services, the quality of users' voice calls is also difficult to guarantee. OTT-based voice communication cannot fully reflect the mobile characteristics of wireless communication, especially OTT methods such as emergency calls, emergency voice communication, and high-quality voice communication are difficult to meet. These demands all require mobile operators to provide reliable guarantees to users through mobile communication network technology. (2) Voice implementation technology based on IMS MMTel Based on operators' mobile and fixed network integration operation and construction requirements, the 3GPP specification defines multimedia voice implementation technology, which is based on the IMS multimedia phone MMTel network technology. Operators based on MMTel technology can provide end users with rich multimedia voice services. The Global Alliance of GSM Mobile Operators clearly defines and promises in the IR.92 specification that in the evolution to the future LTE network, the voice and multimedia services of the mobile network are provided based on the IMS MMTel network technology. MMTel network technology is based on the SIP protocol of IP, which handles the user's voice call at the signaling level. In MMTel providing voice services to end users, MTAS (MulTImedia Telephony ApplicaTIon Server) as the engine of multimedia voice services, together with network elements such as IMS core network equipment CSCF, MGCF and MGF, provide voice services to end users and complete the calling and called Multimedia voice business processing. In the LTE access network scenario that provides voice services based on MMTel, the LTE core network EPC and MMTel interoperate to provide multimedia voice services to LTE terminals. The multimedia voice service can ensure the service quality of telecom operators and provide social functions such as emergency calls and emergency voice communications guaranteed by telecom operators. According to the 3GPP specifications, a major advantage of the MMTel-based multimedia voice service that differs from the OTT voice service is that users can switch voices when roaming in LTE and GSM / WCDMA wireless systems to maintain voice continuity. In the OTT voice scenario, when a user switches from LTE to GSM / WCDMA network, it is difficult to provide a guaranteed voice channel and voice service quality on the GS / WCDMA network. In MMTel-based multimedia voice communication, when users roam from the LTE network to the GSM / WCDMA network, the 3GPP specification clearly defines the interworking interface between the LTE and GSM / WCDMA CS core networks to ensure carrier-grade service quality and continuity of voice services Among them, the important network technology is SRVCC technology (Single Radio Voice CallConTInuity). (3) Voice drop technology Generally, when operators deploy LTE networks, especially in the early stages of LTE network deployment, LTE wireless coverage will be discontinuous. At the same time, MMTel network technology may not be able to form commercial applications due to various reasons during LTE deployment. In order to deal with this network networking situation, the 3GPP specification defines the CSFB (Circuit Switched Fall Back) technology. This network technology defines that when an LTE user terminal registers with an LTE network, it can fall back to the GSM / WCDMA network and perform the calling and called connection processing of the voice based on the CS core network of the GSM / WCDMA network. Like the SRVCC network technology, the CSFB network voice technology is defined and recommended in the GSMA operator enterprise alliance specification IR.92.
The spinning pole is the use of foreign advanced spinning equipment,forming a whole without welding,forming a conical or profiled bar.And then polishing,remove surface oil,burr and indentation.Then after the quenching intensity,to T6 state,in line with international standards.The product never rust ,strong corrosion resistance,diversified surface treatment process,the appearance of simple fluid lines.Light weight and convenient installation and transportation,the rod body can be 100%recycling,low melting temperature.
Product features
â‘ Using spinning equipment advanced,the whole forming a non welding
â‘¡Product permanent does not rust,corrosion resistance
â‘¢Diversified surface treatment technology,make the appearance line succinct smooth
â‘£The light weight,convenient installation and transportation
⑤The rod body can be 100% recycling,melting temperature is low.
Aluminum Alloy Spinning Lighting Pole Aluminum Alloy Spinning Lighting Pole,Lightest Aluminum Alloy,Aluminum Alloy Torchlight,Lightweight Aluminum Alloy Jiangsu chengxu Electric Group Co., Ltd , http://www.chengxulighting.com