There are few technologies that have had a more profound effect on people’s lives than mobile communications. As recently as twenty years ago no one had a mobile phone, while today 1.4 billion men, women and children depend on them. This now exceeds the number of landline users, where it took the preceding one hundred years to reach the 1 billion mark. The ability to make mobile voice calls turns out to be the answer to a deeply felt need across different cultures who simply want to communicate.
标签： Communications Wireless Mobile and
上传时间： 2020-05-30
上传用户：shancjb
Notwithstanding its infancy, wireless mesh networking (WMN) is a hot and growing field. Wireless mesh networks began in the military, but have since become of great interest for commercial use in the last decade, both in local area networks and metropolitan area networks. The attractiveness of mesh networks comes from their ability to interconnect either mobile or fixed devices with radio interfaces, to share information dynamically, or simply to extend range through multi-hopping.
上传时间： 2020-05-31
上传用户：shancjb
In Helsinki during a visiting lecture, an internationally well-known professor in communica- tionssaid,‘Inthecommunicationssocietywehavemanagedtoconvertourproposalsandideas to real products, not like in the control engineering society. They have very nice papers and strong mathematics but most of the real systems still use the old PID controllers!’. As our background is mainly in control as well as communications engineering, we know that this thought is not very accurate. We agree that most of the practical controllers are analog and digital PID controllers, simply because they are very reliable and able to achieve the required control goals successfully. Most of the controllers can be explained in terms of PID. The reasons behind this impressive performance of PID will be explained in Chapter 2.
标签： Communications Engineering Wireless Systems in
上传时间： 2020-06-01
上传用户：shancjb
Notwithstanding its infancy, wireless mesh networking (WMN) is a hot and growing field. Wireless mesh networks began in the military, but have since become of great interest for commercial use in the last decade, both in local area networks and metropolitan area networks. The attractiveness of mesh networks comes from their ability to interconnect either mobile or fixed devices with radio interfaces, to share information dynamically, or simply to extend range through multi-hopping.
标签： Multi-hop Networks WiMAX WiFi Mesh LTE and
上传时间： 2020-06-01
上传用户：shancjb
Sound is simply an airborne version of vibration. The air which carries sound is a mixture of gases. In gases, the molecules contain so much energy that they break free from their neighbors and rush around at high speed. As Figure 1.1(a) shows, the innumerable elastic collisions of these high-speed molecules produce pressure on the walls of any gas container. If left undisturbed in a container at a constant temperature, eventually the pressure throughout would be constant and uniform.
标签： Engineering Audio
上传时间： 2020-06-09
上传用户：shancjb
