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within Newcom Dept. 1 - Cluster 2 Coding Design for OFDM and MIMO Systems Competences and Collaborations. Roberto Bosisio On behalf of Antonio Assalini CNIT unit: University of Padova. November 2nd-3rd, 2005 Barcelona.
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within Newcom Dept. 1 - Cluster 2 Coding Design for OFDM and MIMO Systems Competences and Collaborations Roberto Bosisio On behalf of Antonio Assalini CNIT unit: University of Padova November 2nd-3rd, 2005 Barcelona
(Italy)National Inter-University Consortium for Telecommunications • non-profit consortium • linking 34 Italian Universities • main purpose: to foster research activity and provide networking support to specific projects in the area of telecommunications • 3 universities participating to Newcom Dept.1: Milan, Padova, and Bologna PADOVA Bologna Milan
University of Padova Department of Information Engineering (DEI) • Active engineering degrees in: • Automation engineering • Bioengineering • Electronics • Information engineering • Computer engineering - even teleteaching • Telecommunications • We support other degrees: • Industrial engineering (Chemistry, Mechanical, Electrical), Civil Engineering, Business • Faculty of Medicine • Faculty of Psychology • Faculty of Science of communications • Faculty of Statistics • Faculty of Management … our logo … … and some information … • Academic and Research Personnel • 82 Professors • 92 PhD students and researchers • Staff • 16 Administrative units • 15 Technicians • Students • 3700 Students
1. Competences and Offers for cooperation2. Ongoing collaborations
Competence # 1Coded MIMO-OFDM (1/2) • Design of improved MIMO radio interfaces for OFDM modulated systems • Space-time bit-interleaved coded modulation • Performance evaluation • Transmitter design • Efficient receiver implementation
Offers for Cooperation # 1Coded MIMO-OFDM (2/2) • Coding for OFDMA systems • Besides OFDM, we are interested to other schemes • Single carrier transmissions with cyclic prefix insertion (CP-SC) • Multicarrier modulators adopting shaping filters (Shaped-OFDM, Windowed OFDM, OFDM-OQAM, and Filtered Multitone) • Comparisons among these solutions • Performance evaluation • Transmitter and receiver design • Low complexity solutions • Extension to OFDMA environments
Competence # 2Single CarrierMIMO • Linear and non-linear precoding schemes for the MIMO broadcast channel (MIMO-BC) • Achieving performance close to “dirty paper” coding • Vector precoding with peak power reduction • Study of the optimal beamformer for lattice precoding schemes • Comparison between Tomlinson-Harashima based precoders and vector-perturbation techniques for MIMO channels • Low-complexity joint detectors for SC-MIMO systems • Frequency-domain algorithms for multi-stream interference cancellation (BLAST)
Competence # 3MIMO MC-CDMA • Design of receivers for MC-CDMA systems • Soft interference cancellation techniques • Pre-equalization techniques for MC-CDMA systems • Multi-user pre-equalization for downlink MISO • Single user pre-equalization for uplink • DSP platform for MC-CDMA • Software defined radio platform with • DSP Texas Instruments C6400 • Dual ADC and DAC • FPGA • Algorithms and DSP code to be implemented
Offers for Cooperation # 2-3MIMO MC-CDMA • Receivers design for MIMO multi-user MC-CDMA systems • Investigation on V-BLAST receivers for multiple-input multiple-output (MIMO) extended to multi-user MC-CDMA systems • In particular, the work will focus on finding suitable ordering criteria to demodulate symbols and streams of each user • In uplink coded MC-CDMA systems, possible schemes to iteratively combine V-BLAST detection and decoding will be investigated (turbo principle) • Pre-coded MIMO MC-CDMA systems • Investigation on non-linear precoding schemes for downlink
Competence # 4Cross Layer Optimization • Design of new architectures for performance optimization in wireless networks using a cross layer approach • Quality of service management • Resource allocation • Cognitive radio concept • Opportunistic scheduling • Interference analysis • Multi-cell environment • Intra-inter cell interference analysis • Near capacity performance • High reuse factor
Ongoing Collaborations within Newcom • Joint activity with EURECOM (G. Caire) • F. Boccardi and G. Caire, “The p-sphere encoder: peak power reduction by lattice precoding for the MIMO-BC,” Globecom 2005 • F. Boccardi and G. Caire, "Precoding with Low Peak-Power for the MIMO Gaussian Broadcast Channel”, Allerton Conference, Sept. 2005. • Joint activity with KTH (M. Bengtsson) • M. Butussi and M. Bengtsson, “Low Complexity Admission in Downlink Beamfrorming,” Submitted to ICASSP, Toulouse, France, May 2006. • Joint activity with ETH (H. Bölcskei) • At the beginning of December 2005 a researcher is going to visit ETH University (Communication Theory Group)
About the Joint activity betweenUniversity of Padova and KTH
Low Complexity in Downlink Beamforming • Consider the downlink of a system where N-1 single antenna mobile are served by one or more base stations, each equipped with an antenna array When a new user enters the system The system only modifies the power allocation for the existing user, not the spatial signature of the beamformers. The algorithm is compared to jointly optimal solution, using the COST231 TU channel model, a carrier frequency fo 2.4 MHz, a 500m cell radius and assuming a single base station equipped with 4 element uniform linear array
Numerical Results (1/2) Outage probability when adding a new user to a sytem with 4 and 5 existing users
Numerical Results (2/2) CDF of difference in total power between out proposed and joint optimum when a new user has been added to 4 and 5 existing users
Conclusions • Te user that can be admitted to the system using joint optimal downlink beamforming can almost always also be admitted using this low complexity algorithm, at least if there is a limit on the transmit power References • Martin Schubert and Holger Boche, ”Solution of the multiuser downlink beamforming problem with individual SINR constraints” IEEE Trans. VT, vol 53, no 1, pp 18 -28, Jan 2004
MC-CDMA Giambattista Carnevale SC Precoding MIMO Federico Boccardi Implementation Aspects Roberto Corvaja People involved • Team Head • Prof. Silvano Pupolin • Newcom - Dept. 1 • Prof. Nevio Benvenuto • Tomaso Erseghe • Newcom Cluster 2 • Antonio Assalini antonio.assalini@dei.unipd.it phone: +39.049.827.7752 name.surname@dei.unipd.it