CYBERCOMP.CO.CC: 2.5G, 3G, 3.5G and 4G technology

What is 4G?

4G takes on a number of equally true definitions, depending on who you are talking to. In simplest terms, 4G is the next generation of wireless networks that will replace 3G networks sometimes in future. In another context, 4G is simply an initiative by academic R&D labs to move beyond the limitations and problems of 3G which is having trouble getting deployed and meeting its promised performance and throughput. In reality, as of first half of 2002, 4G is a conceptual framework for or a discussion point to address future needs of a universal high speed wireless network that will interface with wireline backbone network seamlessly. 4G is also represents the hope and ideas of a group of researchers in Motorola, Qualcomm, Nokia, Ericsson, Sun, HP, NTT DoCoMo and other infrastructure vendors who must respond to the needs of MMS, multimedia and video applications if 3G never materializes in its full glory.

Motivation for 4G Research Before 3G Has Not Been Deployed?

3G performance may not be sufficient to meet needs of future high-performance applications like multi-media, full-motion video, wireless teleconferencing. We need a network technology that extends 3G capacity by an order of magnitude.

There are multiple standards for 3G making it difficult to roam and interoperate across networks. we need global mobility and service portability

3G is based on primarily a wide-area concept. We need hybrid networks that utilize both wireless LAN (hot spot) concept and cell or base-station wide area network design.

We need wider bandwidth

Researchers have come up with spectrally more efficient modulation schemes that can not be retrofitted into 3G infrastructure

We need all digital packet network that utilizes IP in its fullest form with converged voice and data capability.

Comparing Key Parameters of 4G with 3G

	3G (including 2.5G, sub3G)	4G
Major Requirement Driving Architecture	Predominantly voice driven - data was always add on	Converged data and voice over IP
Network Architecture	Wide area cell-based	Hybrid - Integration of Wireless LAN (WiFi, Bluetooth) and wide area
Speeds	384 Kbps to 2 Mbps	20 to 100 Mbps in mobile mode
Frequency Band	Dependent on country or continent (1800-2400 MHz)	Higher frequency bands (2-8 GHz)
Bandwidth	5-20 MHz	100 MHz (or more)
Switching Design Basis	Circuit and Packet	All digital with packetized voice
Access Technologies	W-CDMA, 1xRTT, Edge	OFDM and MC-CDMA (Multi Carrier CDMA)
Forward Error Correction	Convolutional rate 1/2, 1/3	Concatenated coding scheme
Component Design	Optimized antenna design, multi-band adapters	Smarter Antennas, software multiband and wideband radios
IP	A number of air link protocols, including IP 5.0	All IP (IP6.0)

What is needed to Build 4G Networks of Future?

A number of spectrum allocation decisions, spectrum standardization decisions, spectrum availability decisions, technology innovations, component development, signal processing and switching enhancements and inter-vendor cooperation have to take place before the vision of 4G will materialize. We think that 3G experiences - good or bad, technological or business - will be useful in guiding the industry in this effort. We are bringing to the attention of professionals in telecommunications industry following issues and problems that must be analyzed and resolved:

Lower Price Points Only Slightly Higher than Alternatives - The business visionaries should do some economic modeling before they start 4G hype on the same lines as 3G hype. They should understand that 4G data applications like streaming video must compete with very low cost wireline applications. The users would pay only a delta premium (not a multiple) for most wireless applications.

More Coordination Among Spectrum Regulators Around the World - Spectrum regulation bodies must get involved in guiding the researchers by indicating which frequency band might be used for 4G. FCC in USA must cooperate more actively with International bodies like ITU and perhaps modify its hands-off policy in guiding the industry. When public interest, national security interest and economic interest (inter-industry a la TV versus Telecommunications) are at stake, leadership must come from regulators. At appropriate time, industry builds its own self-regulation mechanisms.

More Academic Research: Universities must spend more effort in solving fundamental problems in radio communications (especially multiband and wideband radios, intelligent antennas and signal processing.

Standardization of wireless networks in terms of modulation techniques, switching schemes and roaming is an absolute necessity for 4G.

A Voice-independent Business Justification Thinking: Business development and technology executives should not bias their business models by using voice channels as economic determinant for data applications. Voice has a built-in demand limit - data applications do not.

Integration Across Different Network Topologies: Network architects must base their architecture on hybrid network concepts that integrates wireless wide area networks, wireless LANS (IEEE 802.11a, IEEE 802.11b, IEEE 802.11g, IEEE 802.15 and IEEE 802.16, Bluetooth with fiber-based Internet backbone. Broadband wireless networks must be a part of this integrated network architecture.