This question appears in Mumbai University > Wireless Networks subject

Marks: 10 M

Year: Dec 2012

Evolution of IS-95

i. The IS-95 evolved from cdmaOne to cdma2000.

ii. CdmaOne is the family of standards of CDMA technology consisting of IS-95, IS-95A (J-STD-008) and IS-95B.

iii. The cdma2000 is a resultant system that evolves from 2G IS-95, satisfying the requirement of the IMT-2000 system

iv. Cdma2000 provides enhanced services to IS-95A (cdma-One) mobile users. It is designed to be forward and backward compatible in mobile phones.

v. Cdma2000 represents a family of standards.

1. Cdma2000-1xRTT

i. The first 3G CDMA air interface is a system called Cdma2000-1xMC (the MC stands for Multi Carrier) or Cdma2000-1xRTT (Radio Transmission Technology). It implies that a single 1.25 MHz radio Channel is used.

ii. It requires new hardware in base-station controllers, but no new radio interface.

iii. Cdma2000-1xRTT system supports an instantaneous throughput of up to 307 kbps, and typical throughput of up to 144kbps per mobile user. It can also support up to twice as many voice users as the 2G IS-95 CDMA standards.

iv. The Cdma2000 employs a multicarrier operation in which a user is allowed to use 1, 3, 6, or 9 of the cdmaOne Channels to support a more reliable voice and variety of data Channels

2. Cdma2000-1xEV

i. Cdma2000-1xEV is an evolutionary advancement for high-data-rate applications. Using 16-QAM (16-Quadrature Amplitude Modulation) digital modulation technique, the maximum data rate is increased to 2.4 Mbps on the downlink, and 307.2 kbps on the uplink.

ii. Cdma2000-1xEV has the option of providing the mobile users with dedicated services like data only (DO) (Cdma2000-1xEV-DO) or data and voice (DV) (Cdma2000-1xEV-DV).

iii. Cdma 2000 1xEV-DV supports both voice and data users, and can offer usable data rates of up to 144 kbps with about twice as many voice Channels as IS-95B with improved quality of service.

Fig15. CDMA Evolution

3. Cdma2000 3xRTT

i. The Cdma2000 3xRTT standard uses three adjacent 1.25-MHz radio Channels that are used together to provide instantaneous packet data throughput speeds in excess of 2 Mbps per user.

ii. Three non-adjacent radio Channels may be operated simultaneously and in parallel as individual 1.25-MHz Channels or adjacent Channels may be combined into a single 3.75-MHz Channel.

iii. The Cdma2000 can use three separate carriers within a single 5-MHz Channel, each modulated with a chipping rate of 1.2288 Mcps. This is the same rate as used with IS-95, so this variation essentially uses three IS-95 signals in one larger Channel.

Fig16. Multicarrier approach in cdma2000

iv. In fact, the three carriers do not have to be carried in contiguous spectrum; three 1.25-MHz Channels at different points in the spectrum can be used. This is to allow for backward compatibility with the existing IS-95 system.

v. The Cdma2000 system can also use a single carrier operating at a higher chipping rate for new systems where backward compatibility is not required.

4. Additional features of cdma2000

i. The cdma2000 system provides a wide range of implementation options to support data rates (both circuit switched and packet switched) starting from a TIA/EIA-95B compatible rate of 9.6 kbps up to greater than 2 Mbps.

ii. The cdma2000 system can be operated economically in a wide range of environments including outdoor megacells (cell >35 km radius), outdoor macrocells (cell 1–35 km radius), indoor/outdoor microcells (up to 1 km radius), and indoor/outdoor picocells (<50 m radius).

iii. The cdma2000 system can be deployed in indoor/outdoor environments, wireless local loops (WLL), vehicular environments, and mixed vehicular and indoor/outdoor environments.

iv. The cdma2000 system mobility is variable, ranging from fixed wireless to high speeds of up to 300 mph.

v. Cdma2000 supports the 3G wireless intelligent networking (WIN) services and services defined by the ITU or other international standards organizations.

vi. Cdma2000 builds on the inherent advantages of CDMA technologies and introduces other enhancements, such as Orthogonal Frequency Division Multiplexing (OFDM), end-to-end Quality of Service (QoS), and new antenna techniques such as Multiple Inputs Multiple Outputs (MIMO) and Space Division Multiple Access (SDMA) to increase data throughput rates and quality of service, while significantly improving network capacity and reducing delivery cost.