Introduction to Evdo: Physical Channels, Logical Channels, Network, and Operation Ebook Tooltip Ebooks kunnen worden gelezen op uw computer en op daarvoor geschikte e-readers. Physical Channels, Logical Channels, Network, and Operation

Introduction to EVDO explains the fundamentals of the EVDO system, the products it uses, how it operates, what services it can offer, and how EVDO fits and compares with other mobile radio technologies. This book explains how the 1x Evolution (1XEV) data only (EVDO) system modifies (optimizes) the 1.25 MHz IS-95 radio channel structure to provide high-speed data services (up to 2.4 Mbps) to wireless customers. The EVDO system allows cellular service providers carriers to use one of more IS-95 CDMA radio channels (with changes) to provide broadband high-speed data services to their customers. The EVDO is an "always-on" system that allows users to browse the Internet without complicated dialup connections. You will learn that the key types of EVDO devices include external radio modems, wireless PCMCIA cards, embedded radio modules, and mobile telephones. External radio modems allow the customer to simply plug in their EVDO device to their USB or Ethernet data port to their desktop or laptop computer. EVDO PCMCIA cards can be added to most laptop computers or embedded radio modules allow devices such as PDAs and Laptops to integrate high-speed wireless without adding PCMCIA cards. Some CDMA mobile telephones include both IS-95 CDMA (voice and low speed data) and EVDO (high-speed packet data) capability. Because the needs of voice and data communication are different, the airlink design of the IS-95 and EVDO radio channel structures are different. 1xEV devices can have single mode (only EVDO) or dual mode (both IS-95 voice and EVDO data) capability. You will discover how single mode devices can only access the high-speed data rate (HDR) services on the EVDO radio channel and dual mode devices can access either the EVDO HDR channel or the IS-95 voice and medium-rate data traffic channels. This book provides the basic technical components and operation of EVDO technology. You will learn the physical radio channel structures of the 1xEV system along with the basic frame and slot structures. Described are the logical channels and their functions. Explained are the key EVDO network components and how they communicate with each other. Explained is the fundamental capabilities and operation of the EVDO radio channel including asymmetric data rates, adaptive modulation (QPSK, 8-PSK, or 16-QAM), and the use of a single control channel with multiple capabilities. You will discover how a scheduling algorithm can be used to fairly allocate the necessary data rates for EVDO users is provided. Described are the 64 coded channels and how up to 60 of them are available to provide data services to active users and how many other users (possibly 600 per channel) can be added who have a 10% usage activity factor. To make the EVDO data channels transparent with the IS-95 CDMA voice channels, handoffs can occur between IS-95 CDMA radio channels and EVDO radio channels.