Chapter 3 Introduction of Wireless and Mobile Systems

Chapter 3: Introduction of Wireless and Mobile Systems (Part II) Associate Prof. Yuh-Shyan Chen Dept. of Computer Science and Information Engineering National Chung-Cheng University Yschen, CSIE, CCU 1

Outline l PCS l WLL (Wireless Local Loop) l LMDS (Local Multipoint Distribution System) Yschen, CSIE, CCU 2

PCS l Personal communication service ¡Developed out of the need for more capacity and design flexibility than that provided by the initial cellular systems l PCS ¡Narrowband service ¡Offers many enhanced data service ¡The data throughput remained at 9. 6 kbit/s Yschen, CSIE, CCU 3

The Challenge of wideband PCS l Wideband PCS for offering high-speed data has not yet been deployed l The obvious issue ¡is coexistence with the current PCS system ¡The need for more base station due to reduced sensitivity cased by increased bandwidth ¡Is the offering of subscriber units that can act as dual band units Yschen, CSIE, CCU 4

PCS l PCS band was broken into A, B, C, D, E, and F blocks ¡A, B, C blocks involved a total of 30 MHz, while the D, E, and F blocks are allocated 10 MHz. l PCS license boundaries are defined as metropolitan trading areas (MTAs) and basic trading areas (BTAs). l The MTA has several BTAs within its geographic region Yschen, CSIE, CCU 5

PCS l There a total of 93 MTAs and 487 BTAs in USA l All the frequency allocations are duplexed Yschen, CSIE, CCU 6

U. S. cellular spectrum chart Yschen, CSIE, CCU 7

PCS spectrum allocation Yschen, CSIE, CCU 8

WLL (Wireless Local Loop) l The WLL system, is different from the cellular or PCS systems in its application, which is fixed. ¡The fixed service is often referred to as a local multipoint distribution system (LMDS) or ¡A fixed wireless point-to-multipoint (FWPMP) system ¡In many case, WLL is the same as LMDS and FWPMP in its deployment and application Yschen, CSIE, CCU 9

WLL system l WLL is most applicable in areas where local phone service is not available or cost effective l WLL is a system that connects a subscriber to the PTSN or PTT (local telephone company) using a radio link as its transport medium instead of copper wires Yschen, CSIE, CCU 10

WLL Example Yschen, CSIE, CCU 11

More common types of WLL systems l Cellular l PCS l Cordless telephone (CT-2) l Digital European cordless telecommunication (DECT) Yschen, CSIE, CCU 12

WLL l For a developed country ¡ WLL allows for use of a cordless phone as an extension of the house phone or private branch exchange (PBX), which is an added convenience l For a emerging country ¡ Has areas without any access to a communication service ¡ The use of WLL can create profound changes because it is quicker, easier, and less expensive to install than a regular landline system Yschen, CSIE, CCU 13

LMDS (Local multipoint distribution system) l The LMDS is a unique wireless access system whose purpose is to provide broadband access to multiple subscribers in the same geographic area. l The LMDS utilizes microwave radio as the fundamental transport medium and is not really a new technology Yschen, CSIE, CCU 14

LMDS l The LMDS system allows multiple users to access the same radio spectrum l The LMDS is a wireless system that employs cellular-like design and reuse with the exception that there is no handoff l Multiple subscribers (customers) surrounding an LMDS hub or base station Yschen, CSIE, CCU 15

Generic LMDS system Yschen, CSIE, CCU 16

LMDS l The LMDS is a point-to-multipoint system where multiple subscribers can access the same radio platform utilizing both a multiplexing method as well as queuing l Through overbooking l There are Qo. S issues and specific service delivery requirements Yschen, CSIE, CCU 17

LMDS l Provide vastly greater bandwidth requirements and service to a larger population than point-to-point system utilizing the same spectrum can Yschen, CSIE, CCU 18

The key differences between mobile systems and LMDS l The ubiquitous coverage is not required ¡Operator only provide service where the customers are actually located thereby maximizing the capital infrastructure effectiveness and minimizing operating expenses Yschen, CSIE, CCU 19

Example: Multiple Customer Location/Dwelling Unit Yschen, CSIE, CCU 20