At present, the commercialization of LTE is not smooth, and it still faces at least the following three major problems: lack of killer applications; different LTE frequency bands, multi-mode standards have not been unified; LTE tariffs and hardware costs are too high. Fortunately, for Chinese manufacturers, LTE patents are no longer a big problem. In the 3G era, Qualcomm has more than 1,400 core patents, building a high wall that cannot be surpassed on the 3G road. At present, almost all 3G mobile phone manufacturers need to pay Qualcomm royalties, which is approximately 6.5% of mobile phone sales. In the LTE era, the biggest change is that the rules of patent games will change, and the patents owned by Chinese manufacturers have also greatly increased. Usually,10 & 20 layers PCB are HDI board,but some are not .Some with big trace width and space,holes are over 0.3mm too. We have much experience in doing 10 Layer PCB & 20 layer PCB. 10 Layer PCB 10 layer PCB 10 layer TG170 PCB 10 layer design Storm Circuit Technology Ltd , https://www.stormpcb.com
Liu Guangjun, general manager of Lianxin Technology Marketing Department, believes that because the current global distribution of LTE patents is very scattered, there will not be a single phenomenon. In addition, because TDD's frequency bands and operating costs are relatively low, and because patents are relatively scattered, IPR has relatively no high threshold, which can attract more operators and developers to join.
Lack of killer apps
The lack of applications is a major bottleneck that hinders the further development of LTE. At present, LTE applications will mainly focus on high-definition video streaming and other multimedia services and applications that have strict requirements on network speed. Compared with 3G, in addition to the difference in speed, there has not been much revolutionary changes in content services.
ST Francis Ericsson China President Zhang Daijun cited some possible applications and services for LTE in the future: including online online games (low latency and high performance provided by LTE, which are very suitable for online gaming devices), real-time network experience (with instant 3D navigation of scene information), real-time social network information sharing (multimedia files: video, audio, etc.), multimedia streaming, digital home, electronic medical (fast and safe medical information sharing, between patients and doctors through mobile devices HD video conferencing, remote monitoring of patient status), etc.
Liu Guangjun pointed out that "at present, 3G needs to cultivate user habits for 4G. Without the accumulation of 3G data service users, 4G cannot be achieved overnight." Liu Guangjun believes that from 3G to 4G, operators' data service operating income should Will gradually replace voice services, but at present, the business needs of mobile communication users in China are still mainly focused on voice services. It is reported that there are currently three LTE voice solutions in development, one is the CS Fallback technology similar to VoIP, the second is the continuous voice call technology, which has its technical difficulties, and the third voice service dominated by the VoLGA forum. Regardless of the development of the above technologies, GSM, which is already very mature and has excellent coverage, will continue to play an important role for a long time.
However, this situation is changing rapidly, according to Wireless Intelligence data, by 2012, global mobile operators' total revenue will reach 1.1 trillion US dollars, and more than one-third of this revenue comes from non-voice services; Gartner said that mobile data business revenue in 2011 will reach 314.7 billion US dollars, an increase of 22.5% over 2010's 257 billion US dollars. I believe that in a few years, the proportion of data services will definitely exceed that of voice services.
In China, various applications such as video surveillance and wireless cities may be the main direction of the initial application of LTE, but this large-scale data service may first target the government and group users.
A ten-layer board should be used when six routing layers are required. Ten-layer boards, therefore, usually have six signal layers and four planes. Having more than six signal layers on a ten-layer board is not recommended. Ten-layers is also the largest number of layers that can usually be conveniently fabricated in a 0.062" thick board. Occasionally you will see a twelve-layer board fabricated as a 0.062" thick board, but the number of fabricators capable of producing it are limited..
High layer count boards (ten +) require thin dielectrics (typically 0.006" or less on a 0.062" thick board) and therefore they automatically have tight coupling between layers. When properly stacked and routed they can meet all of our objectives and will have excellent EMC performance and signal integrity.
A very common and nearly ideal stack-up for a ten-layer board is shown in Figure 12. The reason that this stack-up has such good performance is the tight coupling of the signal and return planes, the shielding of the high-speed signal layers, the existence of multiple ground planes, as well as a tightly coupled power/ground plane pair in the center of the board. High-speed signals normally would be routed on the signal layers buried between planes (layers 3-4 and 7-8 in this case).
June 19, 2020