Multiple antenna techniques for Wimax systems based on IEEE 802.16d/e standard
Research Area:
Research Lines:
Research Lines:
Collaboration with industry
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Start date: 2005-01-01
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Project abstract
This project includes the research activities developed within several collaboration projects between the Politecnico and Nokia Siemens Networks. The activities aim at the development of advanced signal processing techniques for multi-antenna Wimax systems with fixed/mobile terminals based on the IEEE 802.16 d/e standard.
These systems are designed to support high bit-rate services with strict quality of service requirements thus requiring the employment of innovative technologies as multiple antennas at both edge of the transmission link (MIMO) or the partitioning of the OFDMA transmission in subchannels. Within the project, advanced signals processing algorithms have been proposed with the aim of maximizing the resource allocation efficiency in WiMax MIMO-OFDMA.
Multiple antennas systems can be used to improve the robustness against the multipath fading (spatial diversity), to reduce the co-channel interference (beamforming) or to enhance the transmission rate by spatial multiplexing (SDMA). The performance gain achieved by multiple antennas depends on the antennas spacing (according to the propagation environment topology) and on the precoding/decoding strategy at the transmitter/receiver.
The first part of the research project was focused on the selection of the optimal deployment of the antenna array at WiMax base stations as trade-off between diversity and interference-rejection capability.
The gain provided by the optimized array in terms of coverage and average throughput with respect to conventional deployments has been evaluated through extensive numerical simulations. Then, signal processing techniques that allow to cope efficiently with non-stationary inter-cell interference have been addressed. WiMax systems offer several degrees of freedom in the resource allocation as it is possible to separate the users spatially (SDMA), in frequency (FDMA) and in time (TDMA), thus permitting to schedule the users with the best channel conditions (multiuser diversity). In this context, it has been proposed a cross-layer approach based on the joint optimization of the precoding/decoding at physical layer (PHY) and of the scheduling at Medium Access Control (MAC) layer in order to maximize the average system throughput. Finally, semi-analytic methods have been derived to evaluate the average bit error probability of MIMO-OFDM/OFDMA coded systems over frequency selective (correlated) channels with either stationary or non-stationary multicell interference. The project is closed.
These systems are designed to support high bit-rate services with strict quality of service requirements thus requiring the employment of innovative technologies as multiple antennas at both edge of the transmission link (MIMO) or the partitioning of the OFDMA transmission in subchannels. Within the project, advanced signals processing algorithms have been proposed with the aim of maximizing the resource allocation efficiency in WiMax MIMO-OFDMA.
Multiple antennas systems can be used to improve the robustness against the multipath fading (spatial diversity), to reduce the co-channel interference (beamforming) or to enhance the transmission rate by spatial multiplexing (SDMA). The performance gain achieved by multiple antennas depends on the antennas spacing (according to the propagation environment topology) and on the precoding/decoding strategy at the transmitter/receiver.
The first part of the research project was focused on the selection of the optimal deployment of the antenna array at WiMax base stations as trade-off between diversity and interference-rejection capability.
The gain provided by the optimized array in terms of coverage and average throughput with respect to conventional deployments has been evaluated through extensive numerical simulations. Then, signal processing techniques that allow to cope efficiently with non-stationary inter-cell interference have been addressed. WiMax systems offer several degrees of freedom in the resource allocation as it is possible to separate the users spatially (SDMA), in frequency (FDMA) and in time (TDMA), thus permitting to schedule the users with the best channel conditions (multiuser diversity). In this context, it has been proposed a cross-layer approach based on the joint optimization of the precoding/decoding at physical layer (PHY) and of the scheduling at Medium Access Control (MAC) layer in order to maximize the average system throughput. Finally, semi-analytic methods have been derived to evaluate the average bit error probability of MIMO-OFDM/OFDMA coded systems over frequency selective (correlated) channels with either stationary or non-stationary multicell interference. The project is closed.
Project results
Analysis and optimization of the geometrical antenna pattern in MIMO-OFDM systems; development and performance analysis of transmitting/receiver algorithms based on spatial precoding/decoding in MIMO-OFDM/OFDMA (space-time coding, spatial multiplexing, spatial diversity); development of a physical layer IEEE 802.16 simulator; development of semi-analytical methods for evaluation of the average bit error rate of WiMax multi-cell systems with frequency selective channels, either stationary or non-stationary (due to subcarrier permutation) multicell interference, for different traffic conditions and propagation scenarios; development of spatial multiplexing algorithm for broadcast MIMO-OFDMA systems.
Publications:
Patents:
Publications:
- R. Bosisio, J.L. Vicario, U. Spagnolini, C. Anton-Haro, “Enhanced opportunistic beamforming scheme for practical broadcast systems,” Eur. Trans on Telecomms, vol.18, n.6, pp.605-615, Oct. 2007.
- J. L. Vicario, R. Bosisio, C. Anton-Haro and U. Spagnolini, “Beam Selection Strategies for Orthogonal Random Beamforming in Sparse Networks,” IEEE Trans. Wireless Commun. vol.7, n.9, pp.3385-3396, Sept.2008.
- M. Nicoli, S. Savazzi, O. Simeone, R. Bosisio, G. Primolevo, C. Santacesaria, U. Spagnolini, Deployment and design of multi-antenna WiMax systems in a non-stationary interference environment, in Current Technology Developments of Wimax Systems, edited by Maode Ma, Springer Publications, expected 2008.
- S. Savazzi, M. Nicoli, M. Sternad, “A comparative analysis of spatial multiplexing techniques for outdoor MIMO-OFDM systems with limited feedback constraints, ” IEEE Trans. Vehicular Technology, expected 2008 (see forthcoming articles on ieeexplore).
- M. Nicoli, L. Sampietro, C. Santacesaria, S. Savazzi, O. Simeone, U. Spagnolini, “Throughput optimization for non-uniform linear antenna arrays in multicell WiMAX systems,” Proc. IEEE Workshop on Smart Antennas (WSA’06), Ulm, 13-14 March 2006.
- S. Savazzi, M. Nicoli, M. Sternad, “Spatial multiplexing for outdoor MIMO-OFDM systems with limited feedback costraint,” Proc. IEEE International Conference on Communications (ICC’06), Istanbul, 11-15 June 2006.
- M. Nicoli, M. Sala, L. Sampietro, C. Santacesaria, O. Simeone, “Adaptive array processing for time-varying interference mitigation in IEEE 802.16,” presentato alla conferenza IEEE Personal Indoor and Mobile Radio Communications (PIMRC’06), Helsinki, 11-14 Settembre 2006.
- M. Nicoli, L. Sampietro, C. Santacesaria, U. Spagnolini, D. Archetti, A. Bonfanti, M. Sala, “Deployment and design of multiantenna solutions for fixed WiMax systems,” Proc. 8th European Conference on Fixed Wireless Networks and Technologies (ECRR 2007), Paris, April 2007.
- D. Molteni, M. Nicoli, R. Bosisio, L. Sampietro, “Performance analysis of multiantenna WiMax systems over frequency-selective fading channels,” Proc. IEEE Personal Indoor and Mobile Radio Communications (PIMRC’07), Athens, 3-4 Semptember 2007.
- R. Bosisio, U. Spagnolini, “On the sum-rate of opportunistic beamforming scheme with multiple antennas at the receiver,” Proc. IEEE International Conference on Communications (ICC07), Glasgow 24-27 June 2007, pp.1048-1053.
- R. Bosisio, U. Spagnolini, “Collision model for the bit error rate analysis of multicell multiantenna OFDMA systems (WiMAX),” Proc. IEEE International Conference on Communications (ICC07), Glasgow 24-27 June 2007, pp.5732-5737.
- S. Sorrentino, U. Spagnolini, L. Moretti, “A Distributed Scheduling Algorithm for Multiuser MIMO Systems with 1-bit Feedback,” Proc. IEEE International Conference on Communications (ICC07), Glasgow 24-27 June 2007, pp.5885-5890.
- R. Bosisio, U. Spagnolini, “Efficient feedback quantization for orthogonal random beamforming schemes,” in Proc. IEEE Signal Processing Advances on Wireless Communications (SPAWC 2007), June 17-20, Helsinki (Finland).
- S. Sorrentino, U. Spagnolini, “A predictive opportunistic scheduler for 4G wireless systems,” 16th IST Mobile & Wireless Communication Summit (IST Summit-2007), Budapest (Hungary), July 1-5, 2007.
- S. Sorrentino, U. Spagnolini, “A Predictive Scheduler for FDD Systems Based on the Windowed Empirical CDF,” 4th IEEE International Symposium on Wireless Communication Systems (ISWCS'07), Trondheim, Norway, Oct. 16-19, 2007.
- D. Molteni, R. Bosisio, M. Nicoli, “Analytic framework for performance evaluation of multi-antenna WiMax systems over fading channel,” Proc. IEEE International Conference on Acoustics, Speech, and Signal Processing (ICASSP’08).
- M. Rossi, S. Sorrentino, U. Spagnolini, L. Moretti, Convex Optimization Strategies for Precoding of Broadcast Channels, Proc. International ITG Workshop on Smart Antennas 2008 (WSA 2008), Darmstadt Feb.26-27.
Patents:
- L. Moretti, M. Nicoli, O. Simeone, U. Spagnolini, “Method for the estimation and tracking of channel modes in multicarrier communication systems,” European Patent, n. EP 03425721.2, May 2003.
- M. Nicoli, L. Sampietro, C. Santacesaria, S. Savazzi, O. Simeone, U. Spagnolini, “Method for optimizing the spacing between receiving antennas of an array usable for counteracting both interference and fading in cellular systems”, European Patent.
- M. Nicoli, L. Sampietro, C. Santacesaria, O. Simeone, U. Spagnolini, “Method to improve the channel estimate in broadband SIMO/MIMO cellular radio networks during abrupt interference variations”, European Patent.
- L. Moretti, S. Sorrentino, U. Spagnolini, “Method and apparatus for scheduling communication resources, corresponding communication system and computer program product”, European Patent, n. EP 07425145.5, Mar. 2007.
