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.
This figure shows how the 1XEV system can provide both voice and data interoperation. This diagram shows how a voice call can be received while a user is transferring a file via the high-speed EVDO data session. This diagram shows that the EVDO signaling channel sends a message to the access terminal (the mobile telephone) alerting the user that an incoming call is waiting. If the user accepts the call, the mobile telephone will be transferred from an EVDO data only radio channel to an IS-95 traffic channel.
This figure shows how the 1xEV system uses IS-95 channels for voice and EVDO channels for data transmission. This diagram shows that IS-95 CDMA radio channels has been designed to allow many simultaneous users to transmit with approximately the same data transfer rate. This example shows that the EVDO radio channel is designed to transmit the maximum power/data transfer rate for each user as need to transfer data.
This figure shows how the EVDO radio channel uses a lower spreading gain (less interference protection) to increase the overall data transmission rate. This diagram shows that the IS-95 system uses a relatively high spreading gain (more chips per bit of information) while the EVDO system uses a small amount of spreading gain (less chips per bit of information).
Description
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. An introduction to how a scheduling algorithm is used to fairly allocate the necessary data rates for EVDO users is provided. You will learn about 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.
Some of the most important topics featured in this book are:
• How EVDO provides wireless Broadband data services
• The fundamental components and operation of EVDO systems
• Differences between EVDO data and IS-95 traffic/voice channels
• The types of EVDO products and their uses
• How EVDO services are setup using manual or over the air programming
• The EVDO radio channel structure
• The different types of physical and logical channels
• EVDO network components
• Network connections
• How EVDO technology continues to evolve