在通信专业中，PON的英文全称是“（ ）”，“衰减”英文通常翻译为“（ ） ”。

IPv6 was developed by the （ ） to deal with the long-anticipated problem of IPv4 adderss exhaustion．

There are a number of key technologies that will enable LTE Advanced to achieve the high data （ ） rates that are required．（ ） are two of the base technologies that will be enablers．Along with these there a number of other techniques and technologies that will be employed．

Software defined networking(SDN) is a telecommunications network （ ） that provides the promise of significant improvements in the network （ ）.

【With the 4G telecommunications systems now starting to be deployed,people are looking towards the development of 5th generation or 5G technology services.Although the deployment of any wireless or cellular system take years,development of the 5G technology systems is being investigated.The new 5G technologies will need to be chosen developed and perfected to enable timely and reliable deployment. The new 5th generation,5G technology for cellular systems will probably start to come to fruition around 2020. The current status of the 5G technology for cellular systems is very much in the early development stages.Many companies are looking into the technologies that could be used to become part of the system.In addition to this,a number of universities have set up 5G research units focused on developing the technologies for 5G. In addition, the standards bodies,particularly 3GPP are aware of the development but are not actively planing the 5G systems yet.Many of the technologies to be use

【问题1】光纤的中心是（1） ，其外层是（2） ，中心折射率（3）于外层折射率，从而形成光波导效应，实现光信号的传输。按照光纤的折射分布来分，可分为（4）光纤和（5）光纤。光纤模式是满足边界条件的电磁场波动方程的解，按照传输模式数目来分，光纤可以分为（6）光纤和（7）光纤。 【问题2】光纤色散和非线性效应极大地影响着信号传输质量，其中，光纤的色散主要分为（1）色散、（2）色散两大类；非线性效应分受激散射效应和非线性折射效应两类，而非线性折射效应主要包括（3） 、（4） 、（5）三种效应。