IMEC software-defined radio concept compliant with 3GPP-LTE

June 26, 2006 - Leuven, Belgium -- IMEC, Europe's leading independent nanoelectronics and nanotechnology research institute, shows at Cannes on the air 3GPP-LTE compliant data transmission, from a first FPGA-based hardware-software prototype of its flexible air interface (FLAI) platform. IMEC also demonstrates a software transaction-level model representation of this FLAI platform, as first implementation step towards a 90nm chip-tape-out of the FLAI-SDR (software-defined radio) platform beginning next year.

3GPP-LTE-like transmission is demonstrated wirelessly over the air with real-time transmission and non-real-time receiver post processing on IMEC’s first prototype of its FLAI platform. The system makes use of novel terminal synchronization and analog front-end non-ideality compensation (crystal frequency offset, IQ imbalance, phase noise) techniques to achieve a high spectral efficiency. IMEC has patented a technique to acquire the carrier frequency offset (CFO) in the presence of IQ imbalance, based on a newly designed preamble. The accuracy of the CFO estimation is very high, achieving a few hundreds Hertz for a typical IQ imbalance. This technique enables successful demodulation of a 64QAM constellation at the receiver and therefore realizes the high data rate promises of the 3GPP LTE air interface in practice. In the demonstration, the received constellation (after channel equalization) is compared to the original one. By activating and deactivating the front-end compensation mechanisms, it is possible to evaluate their effects. The real-time transmit baseband processing is mapped on a VLIW processor and shows the feasibility of implementing a 3GPP-LTE transmitter at low complexity on a software-defined radio.

IMEC also developed a transaction-level model of the complete transmit/receive SDR platform, to support a wide range of standards including 3GPP-LTE, 802.11n, 802.16e and DVB-h. Besides a baseband processor, it includes an ARM processor, a digital front-end core, a forward-error-coding unit and a direct memory access engine for accelerating data transfers. The model allows verifying the complex data movement and synchronization between different blocks of the architecture.

These results were obtained within IMEC’s M4 program in which IMEC is building a heterogeneous multi-processor system-on-chip platform enabling flexible implementation of most wireless communication standards at low power. Such a solution is desired by the industry to enable seamless connectivity with first generations of SDR-based mobile terminals and handhelds operating at limited battery energy. The functionality support spans from cellular (CDMA) to next-generation high data rate WLAN-WiMAX-DVB (OFDM-MIMO) standards.

A cross-layer power manager will exploit the scalability and heterogeneity of the platform to enable minimal power for the different operation modes. A white-box design environment allows building scalable retargetable virtual platforms and supports hardware software co-design. It enables efficient development by IMEC partners of their proprietary wireless SDR platforms based on IMEC's FLAI research results.

IMEC’s SDR platform comes with an optimized baseband 2D processor based on IMEC’s reconfigurable processor, ADRES. A tool suite including a C-compiler is developed together with the ADRES core. Experiments have already demonstrated that the unique ADRES architecture achieves record breaking performance/power of ~0.35mW/MHz by efficiently supporting instruction-level parallelism and data-level parallelism.

A digital front-end ASIP-core (DFE) which detects incoming wireless signals is added to interact with the SDR baseband processor. This enables a first of a kind SDR solution that supports low standby power (~2mW) during idle mode, whilst supporting efficient wake-up of the SDR-baseband processor on incoming multi-mode signals. The DFE functionality together with the high power efficiency of the ADRES core integrated into IMEC's SDR-FLAI solution, will support industry to overcome the major roadblocks for introducing SDR-based baseband in future mass volume mobile terminals.

The SDR solution is completed by an IMEC proprietary SDR radio front-end with building blocks that are designed to offer flexibility in carrier frequency, channel bandwidth, noise performance, etc. without a significant power penalty.

About IMEC

IMEC is a world-leading independent research center in nanoelectronics and nanotechnology. Its research focuses on the next generations of chips and systems, and on the enabling technologies for ambient intelligence. IMEC’s research bridges the gap between fundamental research at universities and technology development in industry. Its unique balance of processing and system know-how, intellectual property portfolio, state-of-the-art infrastructure and its strong network of companies, universities and research institutes worldwide position IMEC as a key partner for shaping technologies for future systems.

As an expansion of its wireless autonomous microsystems research, IMEC has created a legal entity in the Netherlands. Stichting IMEC Nederland runs activities at the Holst Centre, an independent R&D institute that develops generic technologies and technology platforms for autonomous wireless transducer solutions and systems-in-foil.

IMEC is headquartered in Leuven, Belgium, and has representatives in the US, China and Japan. Its staff of more than 1450 people includes more than 500 industrial residents and guest researchers. In 2005, its revenue was EUR 197 million. Further information on IMEC can be found on www.imec.be.