5.6 Enhancement to IS-136 Standard


To meet the increasing demand and needs of data markets, the IS-136 TDMA community standardized several evolutionary features. In this section these features are briefly described, since to date they have not been adopted or implemented (IS-136 operators have decided to migrate to GSM and UMTS technology for future network deployments).

Several aspects characterize the evolution for IS-136: improved coverage and voice quality, higher spectral efficiency and capacity, indoor services, new data services and application support, and a set of new end- user devices. This evolution addresses a wider market segment and range of use.

A key to the evolution of IS-136 toward third-generation systems is the ability to provide higher data rates by increasing spectral efficiency. The main driver for third-generation wireless communication is the ability to supplement standardized services currently available in GSM and TDMA/136 with wideband services.

The GSM system has been evolving in the last few years with the introduction of improved support for data communications over the air interface (e.g., high-speed CS data, EDGE radio interface) and packet data services (GPRS). For TDMA/136 evolution, similar standardization activities have been taking place. In particular, 136+, 136 HS, and EGPRS-136 have been defined.

5.6.1 IS-136+

IS-136+ is an improvement of IS-136 to support faster data support. IS-136+ uses the combination of multislot operation and a new modulation scheme, 8-PSK (based on the 30-KHz carrier bandwidth), which allow for increased data rates (by approximately four times).

5.6.2 IS-136 HS

IS-136 HS is based on EDGE, a new radio interface technology with enhanced modulation, and increases the data throughput of IS-136 systems to over 473 Kbps per carrier. There are two variants of 136HS in IS-136 systems, EDGE Classic and EDGE Compact. 136HS will be available in both 850 MHz and 1900 MHz IS-136 systems. EDGE Classic is the same as EDGE in GSM systems and is designed for systems with a spectrum of 2.4 MHz or more. EDGE Compact, on the other hand, is designed for IS-136 systems, where the amount of available spectrum for initial deployment of the wireless data solution is limited to 1 MHz. The requirements for 136 HS include flexible spectrum allocation, high spectral efficiency, compatibility with TDMA/136 and 136+, and support for macrocellular performance at high mobile-terminal velocity (in particular, initially this should not require clearance of more than 1 MHz of spectrum). 136 HS is able to coexist with second-generation systems in the same spectrum but without degrading their performance. The introduction of EDGE in 136 HS requires only minor changes to the network elements, mainly in the radio part.

5.6.3 EGPRS-136 HS

EGPRS-136HS introduces the packet-switched GPRS services and provides the same advances in IS-136 systems as that offered by EGPRS in GSM systems, namely higher data rates and "always online" direct Internet connectivity. This enables greater sophistication as end-user services move toward personal multimedia. More information on GPRS is provided in Chapter 8.

The use of the same basic technology, EGPRS, in both IS-136 and GSM systems makes global data roaming possible between these two systems and leads to the possibility of convergence of IS-136 and GSM systems. EGPRS-136HS network elements are overlaid on top of existing IS-136 networks and provide packet data services that add to the circuit switched services currently provided by the IS-136 networks.

IS-136 circuit switched services and GPRS packet switched services over 136+ or 136 HS air interfaces are supported from the same base station; therefore, operators can efficiently reuse existing infrastructure.



IP in Wireless Networks
IP in Wireless Networks
ISBN: 0130666483
EAN: 2147483647
Year: 2003
Pages: 164

flylib.com © 2008-2017.
If you may any questions please contact us: flylib@qtcs.net