2G、3G、4网络区别

　 2G、3G、4G网络区别

　2G，是第二代（Second Generation）移动通信技术规格的简称，相对于前一代直接以类比方式进行语音传输，2G移动通信系统对语音系以数字化方式传输，除具有通话功能外，某些系统并引入了短信（SMS，Short message service）功能。在某些2G系统中也支持资料传输与传真，但因为速度缓慢，只适合传输量低的电子邮件、软件等信息。

　基本信息

　1.1 容量

　　在手机与基站间使用数字信号增加了系统容量，主要体现在这两个方面：

　　通过使用不同的编码技术，数字信号可被比模拟信号更有效地压缩与编码，从而允许在同一带宽中传播更多的信号。

　　数字系统减少了手机发射信号所需要的能量，这意味着蜂窝网络需要变得更小，所以相同的面积需要部署更多的蜂窝，因为基站与手机的廉价使这一切成为了可能。

　1.2 劣势

　　在人口较少的区域，微弱的手机信号可能无法有效到达基站，这个问题对于在较高频率工作的2G系统尤为明显，对在低频工作的2G系统并不是那么明显。在不同的国家，对于2G的可部署位置，也有着截然不同的法规。

　数字信号是有损压缩，而模拟信号是无损压缩。

　1.3 优势

　　数字信号通过降噪技术，较少受到白噪声和背景噪声的干扰。

　2 技术标准

　　2G技术基本可被切为两种，一种是基于TDMA所发展出来的以GSM为代表，另一种则是CDMA规格，复用﹙Multiplexing﹚形式的一种。

　　主要的第二代手机通讯技术规格标准有：

　　GSM：基于TDMA所发展、源于欧洲、目前已全球化。GSN处理器

　　IDEN：基于TDMA所发展、美国独有的系统。被美国电信系统商Nextell使用。

　　IS-136﹙也叫做D-AMPS﹚：基于TDMA所发展，是美国最简单的TDMA系统，用于美洲。

　　IS-95﹙也叫做cdmaOne﹚：基于CDMA所发展、是美国最简单的CDMA系统、用于美洲和亚洲一些国家。

　　PDC﹙Personal Digital Cellular﹚：基于TDMA所发展，仅在日本普及。[1]

　4g和3g的区别?现在大家最关注的新闻无疑就是4g网络的到来啦，4g牌照采用的我国自主开发的TD-LTE技术,和3g网络还有一些区别的，下面小编为大家详细阐述区别到底在哪？

　　4g手机和3g手机的区别就是4g手机可以支持更快的数据传输，其他功能是一样的。4g手机也只有在使用4g网络的时候才可以达到那么高的速度。全球的4g标准有3个：中国移动的TD-LTE，联通的HSPA+，还有WIMAX。TD-LTE可以达到100M，HSPA+可以达到42M 还可以更快 ，WIMAX可以达到150M。

　1.网络制式的区别

　　3G手机的发放的3G牌照标准是TD-SCDMA，TD-SCDMA全称为Time Division - Synchronous CDMA 时分同步CDMA ，该标准是由中国大陆独自制定的3G标准；4G手机的发放的4G牌照标准是TDD-LTE制式，TDD-LTE主要是采用时分，所以上下行设备有所不同，这样也就造成了在建设上成本较多。

　　2.网络的区别

　　4G比3G上网速度快！本身功能还要看手机本身，支持4G网络，不管哪个系统都会支持的！4G的好处是上网速度快，可视电话会更加流畅。全面4G网络建设将为后续支撑系统（传输网络、运营管理、计算中心）建设将带来巨大的市场。

　　3.传输速度的区别

　　4G最大的数据传输速率超过100Mbit/s，这个速率是目前移动电话数据传输速率的1万倍，也是3G移动电话速率的50倍，4G网络具有约20倍于3G网络的下行速度与承载能力，将为移动互联网产业的发展提供广阔的市场发展空间。

　and performance test copies of the record. If necessary, review should be carried out; 4 for spring hangers included simple spring, hangers and constant support hangers it should also be recognized as setting and locking of loads. 5 check the surface quality, folded layering and without cracks, rust and other defects. 5 after completion of the test and control drawing number one by one, by series baled. Color alloy steel parts, the parts marking installation location and rotation about the direction you want. 7.3.14. hangers installation 7.3.14.1 hanger layout a. a clear design of hanger should be installed strictly in accordance with the drawings and designs shall not be installed wrong, missing, etc. B. own arrangement of piping support and hanger set and selection should be based on comprehensive analysis of general layout of piping systems; cold installation of steam pipe with particular attention reserved for compensation of thermal expansion displacement and orientation. C. support systems should be rational to withstand pipe loads, static load and incidental load; reasonable piping displacement; guaranteed under various conditions, stress are within the allowed range. Strength, stiffness, and meet requirements to prevent vibration and soothing water, without affecting the adjacent equipment maintenance and other piping installation and expansion. D. equipment connected to the interface to meet pipeline thrust torque limit requirements; increase the stability of piping systems to prevent pipeline ... Tube wall thickness mm 2-3 4-6 7-10 weld form no slope mouth weld strengthening height h mm 1-1.5 1.5-2 weld width b mm 5-6 7-6 has slope mouth weld strengthening height h mm 1.5-2 2 weld width b mm cover had each edge slope mouth about 2 mm argon arc welding weld strengthening surface height and width tube wall thickness mm 2--3 3--4 5--6 weld form weld strengthening height h mm 1-1 .5 1.5-2 2-2.5 width b mm

　and performance test copies of the record. If necessary, review should be carried out; 4 for spring hangers included simple spring, hangers and constant support hangers it should also be recognized as setting and locking of loads. 5 check the surface quality, folded layering and without cracks, rust and other defects. 5 after completion of the test and control drawing number one by one, by series baled. Color alloy steel parts, the parts marking installation location and rotation about the direction you want. 7.3.14. hangers installation 7.3.14.1 hanger layout a. a clear design of hanger should be installed strictly in accordance with the drawings and designs shall not be installed wrong, missing, etc. B. own arrangement of piping support and hanger set and selection should be based on comprehensive analysis of general layout of piping systems; cold installation of steam pipe with particular attention reserved for compensation of thermal expansion displacement and orientation. C. support systems should be rational to withstand pipe loads, static load and incidental load; reasonable piping displacement; guaranteed under various conditions, stress are within the allowed range. Strength, stiffness, and meet requirements to prevent vibration and soothing water, without affecting the adjacent equipment maintenance and other piping installation and expansion. D. equipment connected to the interface to meet pipeline thrust torque limit requirements; increase the stability of piping systems to prevent pipeline ... Tube wall thickness mm 2-3 4-6 7-10 weld form no slope mouth weld strengthening height h mm 1-1.5 1.5-2 weld width b mm 5-6 7-6 has slope mouth weld strengthening height h mm 1.5-2 2 weld width b mm cover had each edge slope mouth about 2 mm argon arc welding weld strengthening surface height and width tube wall thickness mm 2--3 3--4 5--6 weld form weld strengthening height h mm 1-1 .5 1.5-2 2-2.5 width b mm

　and performance test copies of the record. If necessary, review should be carried out; 4 for spring hangers included simple spring, hangers and constant support hangers it should also be recognized as setting and locking of loads. 5 check the surface quality, folded layering and without cracks, rust and other defects. 5 after completion of the test and control drawing number one by one, by series baled. Color alloy steel parts, the parts marking installation location and rotation about the direction you want. 7.3.14. hangers installation 7.3.14.1 hanger layout a. a clear design of hanger should be installed strictly in accordance with the drawings and designs shall not be installed wrong, missing, etc. B. own arrangement of piping support and hanger set and selection should be based on comprehensive analysis of general layout of piping systems; cold installation of steam pipe with particular attention reserved for compensation of thermal expansion displacement and orientation. C. support systems should be rational to withstand pipe loads, static load and incidental load; reasonable piping displacement; guaranteed under various conditions, stress are within the allowed range. Strength, stiffness, and meet requirements to prevent vibration and soothing water, without affecting the adjacent equipment maintenance and other piping installation and expansion. D. equipment connected to the interface to meet pipeline thrust torque limit requirements; increase the stability of piping systems to prevent pipeline ... Tube wall thickness mm 2-3 4-6 7-10 weld form no slope mouth weld strengthening height h mm 1-1.5 1.5-2 weld width b mm 5-6 7-6 has slope mouth weld strengthening height h mm 1.5-2 2 weld width b mm cover had each edge slope mouth about 2 mm argon arc welding weld strengthening surface height and width tube wall thickness mm 2--3 3--4 5--6 weld form weld strengthening height h mm 1-1 .5 1.5-2 2-2.5 width b mm