Long term evolution (LTE) – an emerging solution
01 November 2007
Jan Whitacre, LTE programme manager for Agilent’s Electronics Measurement Group (below), explains the next generation of cellular technology.
LTE (long term evolution) is the next generation cellular technology proposed by 3GPP Standards Committees. Increasing the data rate is critical for supporting applications such as music downloads, video calls, internet browsing and TV services. Release 8 aims to increase cell data capacity by at least five times over the current implementations of HSPA and is proposed to be finalised in 2009. It is intended to provide the same level of performance as wired DSL speeds that are available today.
Support for the higher speed channel and increased transmission reliability comes from the new OFDM-based (orthogonal frequency division multiple access) air interface and MIMO (multiple input multiple output) diversity. OFDM enables less complex implementation of advanced antennae and MIMO technology. MIMO technology provides data from independent transmit and receive channels which is combined to maximise reception.
Channel bandwidths from 1.25MHz to 20MHz are supported in the standard, with ultimate performance requiring a 20MHz spectrum allocation, and providing a headline cell data rate of 100Mbit/sec.
Test challenges
Chipset developers are now in a position where they must create a new design to work to these new standards. A challenge lies in the changing block diagram of both network and user equipment. Standards such as DigRF are moving handset design to rely more heavily on ‘software radio’ architectures, which allow developers greater flexibility to upgrade their capabilities. Such systems use greater integration of digital and RF into single devices, changing traditional test interfaces and using software correction in the digital domain to achieve desired RF performance. These changes require new measurement processes and equipment to allow the correlation of digital and RF data.
For the digital-to-RF interface, Agilent provides a variety solutions which range from RF generation and analysis to logic analysis to complete system simulation. Connecting these products together combines real-world measurements with simulation data and allows both RF and digital data to be viewed.
Contact Details and Archive...
Related Articles...
Most Viewed Articles...