Homepage of Geir Oien (ien)

Geir E. ien
Full Professor, PhD, Senior Member of the IEEE
Signal Processing Group, Department of Electronics and Telecommunications
Faculty of Information Technology, Mathematics and Electrical Engineering
Norwegian University
of Science and Technology (NTNU)
Contact details
Postal address: Geir
E. ien
Institutt for
elektronikk og telekommunikasjon (IET)
NTNU
N-7491
Trondheim
NORWAY
E-mail: geir.oien
at iet.ntnu.no
Office phone: +4773594315
Mobile phone: +4793455408
Fax: +4773592640
Webpage: http://www.iet.ntnu.no/~oien
Secretary: Mrs.
Kirsten Ekseth, +47734594318
Visits: Office
C349 in
building Elektroblokk
C
OS Bragstads
plass 2A
NTNU
– Glshaugen
Geir Egil ien (Oien) was born in Trondheim, Norway in 1965. He received the MScEE and the
PhD degrees, both from the Norwegian
Institute of Technology (NTH) in Trondheim, Norway, respectively in 1989
and 1993. From 1994 to 1996 he was an Associate Professor with Stavanger University College in
Stavanger, Norway. In 1996, he joined NTNU as an Associate Professor, and in
2001 was promoted to Full Professor. During the academic year 2005-2006 he
was visiting professor with Institut
Eurcom in Sophia-Antipolis,
France. From August 2009 to August 2013 he will be on leave from his
professorship in order to serve as Faculty Dean of NTNUs Faculty of Information Technology,
Mathematics, and Electrical Engineering.
Prof. ien is the author or
co-author of more than 110 scientific publications
in refereed international fora (for full list sorted
by year, see end of page). He currently supervises or co-supervises 12 PhD students, and has formerly
graduated 9 PhD students (for full list, see below). He participates in,
manages, and/or coordinates a number of national and international projects and
networks of collaboration (for list, see below). His current research
interests are in communication theory, information theory, and signal
processing for wireless communications and sensor networks, with particular
emphasis on link adaptation, power control, radio resource allocation, dynamic
spectrum sharing, interference management, access schemes, and cross-layer
design.
CUBAN - Co-optimized Ubiquitous
Broadband Access Networks
CROPS - CRoss-layer
OPtimization in Short-range wireless sensor networks
CROPS2 – Cross-layer
OPtimization in wireless Sensor networks for Spectrum sensing
SECOMAS – Spectrally Efficient
COMmunications for future Aeronautical Services
SENDORA
– SEnsor Network for Dynamic and cOgnitive RAdio (STREP, EU 7FP Call 1)
CORAL – Cooperative and
Opportunistic Resource ALlocation in wireless networks
BEATS - Bandwidth-Efficient and
Adaptive Transmission Schemes for wireless multimedia communications (ended
2007)
TURBAN -
TURBo codes, Access and Network technologies related to UMTS (ended 2005)
WIRAC - WIdeband Radio Access
(ended 2002)
COST2100
– Pervasive Mobile and Ambient Wireless Communications
NEWCOM - Network of Excellence in
Wireless COMmunications (ended 2007)
COST 273 - Towards Mobile Multimedia
Broadband Networks (ended 2005)
COST 289 - Spectrum and Power
Efficient Broadband Communications (ended 2006)
Main external collaborators
Prof. Mohamed-Slim Alouini (Texas
A&M University at Education City, Qatar)
Prof. David Gesbert (Institut Eurcom,
Sophia-Antipolis, France)
Prof.
Aawatif Menouni Hayar (Institut Eurcom, Sophia-Antipolis, France)
Prof. Kjell Jrgen Hole (University
of Bergen, Bergen, Norway)
Dr. Pl Orten (ABB CRC and UniK,
Oslo, Norway)
Prof. Mat
Brandt-Pearce (Univ. of Virginia, USA)
Prof. Mikael Skoglund (Royal Institute
of Technology (KTH), Stockholm, Sweden)
Prof. Hong-Chuan Yang (University of
Victoria, Victoria, Canada)
Vesna Gardasevic (co-supervisor; from November 2008)
Elissar Khloussy (co-supervisor, from September 2008)
Yuehong Gao (co-supervisor, from September 2008)
John Torjus Flm (co-supervisor, from June 2008)
Nurul Mahmood (from June 2008)
Luxmiram Vijayandran (co-supervisor; from June 2008)
Jawad Rasool (2007 – present)
Hessam Moussavinik (co-supervisor; 2007 – present)
Mariam Kaynia (2007 – present)
Majid Butt (co-supervisor; 2006 – present)
Changmian Wang (2006 - present)
Asghar Havashki (co-supervisor, 2004 - present)
Anders
Gjendemsj (graduated November 2007; currently with PricewaterhouseCoopers; thesis found here)
Frode Bhagen (co-supervisor; graduated June 2007; currently
with Telenor R&I)
Fredrik Hekland
(co-supervisor; graduated June 2007; currently with ABB Corporate Research
Center; thesis found here)
Sbastien F. G. M. de la Kethulle de Ryhove (graduated April
2007; currently with Electromagnetic Geoservices
(EMGS); thesis found here)
Vegard Hassel (graduated March 2007; currently with Telenor R&I; thesis found here)
Duc Van Duong
(graduated September 2006; currently with The Norwegian Defense Research
Establishment (FFI); thesis found here)
Bengt
Holter (graduated June 2005; currently with SINTEF ICT; thesis
found here)
Ola Jetlund (graduated April 2005; currently with Oslo University College;
thesis found here)
Henrik Holm
(graduated April 2002; currently with Honeywell Corp.; thesis found here)
Dr. Anna Kim (from
October 2008; 24 months NFR fellowship)
Dr. Chung-Shue
(Calvin) Chen (2007 – 2008; 9 months ERCIM
fellowship)
Dr. Liuguo Yin (2007
– 2008; 12 months ERCIM fellowship)
Dr. Hend Koubaa
(2004 – 2005; 9 months ERCIM fellowship)
Dr. Henrik
Holm (2002 – 2004; 24 months NTNU
fellowship)
Other guest researchers and international visitors
hosted
Prof.
Mohamed-Slim Alouini (Texas A&M University at Education City, Qatar)
Prof. Mat Brandt-Pearce (Univ. of Virginia,
USA)
Prof.
David Gesbert (Institut Eurcom, Sophia-Antipolis, France)
Prof. Aawatif Menouni Hayar (Institut Eurcom, Sophia-Antipolis,
France)
Prof.
Phil Schniter (Ohio State University, Columbus, Ohio, USA)
Prof.
Hong-Chuan Yang (University of Victoria, Victoria, Canada)
TTT4160
Mobile communications (4th year MSc level)
TTT09 Communication
and coding theory for wireless channels (5th year MSc level)
TT8106 Selected
topics in communication theory for wireless channels (PhD level)
2009:
1. S. G. Kiani,
D. Gesbert, A. Gjendemsj, and G. E. ien, Distributed Power Allocation for Interfering Wireless
Links Based on Channel Information Partitioning, to appear in IEEE
Transactions on Wireless Communications.
2. S. de la
Kethulle de Ryhove, G. E. ien, and F. Bhagen, Maximizing the Average
Spectral Efficiency of Dual-Branch MIMO Systems with Discrete Rate Adaptation,
IEEE Transactions on Vehicular Technology., vol. 58, no. 2, pp.
1003 – 11011, February 2009.
3.
F. Bhagen, P. Orten, and G. E. ien, On Spherical
vs. Plane Wave Modeling of Line-of-Sight MIMO Channels, IEEE Transactions on Communications,
vol. 2, no. 57, February 2009.
4. Y. Zhang, J.
Xiang, Q. Xin, and G. E. ien, Optimal sensing cooperation for
spectrum sharing in cognitive radio networks, to appear in Proc. European
Wireless 2009 (EW-09), lborg, Denmark, June 2009.
5. M. Kaynia, G.
E. ien,
and N. Jindal, Impact of fading on the performance of ALOHA and CSMA, to
appear in Proc. IEEE SPAWC 2009, Perugia, Italy, June 2009.
6. A. Havashki,
L. Lundheim, P. G. Kjeldsberg, O. Gustafsson, and G. E. ien, Analysis of switching activity in DSP signals in the presence of noise, Proc.
IEEE EUROCON-2009, St. Petersburg, Russia, May 2009.
2008:
1. B. Holter and
G. E. ien, Performance Analysis of a Rate-Adaptive Dual-Branch
Switched Diversity System, IEEE Transactions on Communications, vol. 56,
no. 12, pp. 1998 – 2001, December 2008.
2. F. Bhagen,
P. Orten, G. E. ien, and S. de la Kethulle de Ryhove, Exact
Capacity Expressions for Dual-Branch Ricean MIMO Systems, IEEE
Transactions on Communications, vol. 56, no. 12, pp. 2214 – 2222,
December 2008.
3. B. Zayen, M.
Haddad, A. M. Hayar, and G. E. ien, Binary Power
Allocation for Cognitive Radio Networks with Centralized and Distributed User
Selection Strategies, Elsevier Physical Communication Journal, vol. 1, no.
3, pp. 183 – 193, September 2008 (invited paper). Cf. http://dx.doi.org/10.1016/j.phycom.2008.09.002
.
4.
A. Gjendemsj, D. Gesbert, G. E. ien, and S. G.
Kiani, Binary
Power Control for Sum Rate Maximization over Multiple Interfering Links, IEEE
Transactions on Wireless Communications, vol. 7, no. 8, pp.
3164 – 3173, August 2008.
5. S. de la Kethulle de Ryhove, N. Marina, and G. E. ien, On the Capacity and Mutual Information of Memoryless Noncoherent
Rayleigh-Fading Channels, IEEE Transactions on Information Theory, vol. 54,
no. 7, pp. 3221 – 3231, July 2008.
6.
A. Gjendemsj, H.-C. Yang, G. E. ien, and M.-S.
Alouini, Joint Adaptive Modulation and Diversity Combining with Downlink Power
Control, IEEE Transactions on Vehicular Technology, vol. 57,
no. 4, pp. 2145 – 2152, July 2008.
7. S. de la Kethulle de Ryhove, G. E. ien, and L. Lundheim, An Efficient Design Methodology for Constant Power Link Adaptation Schemes in Short-Range
Scenarios, IEEE Transactions on Vehicular Technology, vol. 57, no. 4, pp. 2132 – 21544, July 2008.
8. L. Yin, C.
Wang, and G. E. ien, On the Minimization of Communication Energy
Consumption of Correlated Sensor Nodes, Wireless Personal Communications, Springer
Netherlands, 11 pages, June 2008. DOI:
10.1007/s11277-008-9541-y.
Cf. http://www.springerlink.com/content/r91215205tmln710/ .
9. A.
Gjendemsj, G. E. ien, H. Holm, M.-S. Alouini, D. Gesbert, K. J.
Hole, and P. Orten, Rate and Power Allocation for Discrete-Rate Link
Adaptation, EURASIP Journal of Wireless Communications and Networking, Volume 2008, Article ID 394124, 11 pages, 2008. DOI: 10.1155/2008/394124. Available
at
http://www.hindawi.com/GetArticle.aspx?doi=10.1155/2008/394124 .
10.
D. V. Duong, B. Holter, and G. E. ien, Analysis
and Optimization of Adaptive Coded Modulation Systems in Spatially Correlated
SIMO Rayleigh Fading Channels, IEEE Transactions on Vehicular Technology, vol. 57,
no. 3, pp. 1929 – 1934, May 2008.
11. C.-S. Chen,
K. W. Shum, C. W. Sung, W. S. Wong, and G. E. ien, User
un-suppressible protocol sequences for collision channel without feedback, in Proc. ISITA-2008, Auckland,
New Zealand, December 2008.
12. C.-S. Chen
and G. E. ien, Optimal power allocation for two-cell sum
rate maximization under minimum rate constraints, in Proc. IEEE
ISWCS-08, Reykjavik,
Iceland, October 2008.
13. A. Havashki,
L. Lundheim, P. G. Kjeldsberg, and G. E. ien, A study of the effect
of finite coefficient word lengths on channel estimator performance, in Proc.
The
9th International Conference on Signal Processing
(ICSP'08),
Beijing, China, October 2008.
14. C. Wang, L. Yin,
and G. E. ien, Energy-efficient adaptive route configuration
for wireless ad-hoc networks under hard delay constraints, in Proc. CONET-08, London, UK,
September 2008.
15. L. Yin, C.
Wang, and G. E. ien, Minimum cost routing with optimized data
fusion for event-driven dense wireless sensor networks, in Proc. IEEE
PIMRC-08,
Cannes, France, September 2008.
16. M. Haddad, A.
M. Hayar, and G. E. ien, Downlink distributed binary power allocation
for cognitive radio networks, in Proc. IEEE PIMRC-08, Cannes,
France, September 2008.
17.
M. Kaynia, G. E. ien, N. Jindal, and D.
Gesbert, Comparative performance evaluation of MAC protocols in ad hoc
networks with bandwidth partitioning, in Proc. PIMRC-08, Cannes,
France, September 2008 (invited).
18.
A. Gjendemsj, S. de la Kethulle de Ryhove, and G. E.
ien,
Spectral efficiency vs. feedback load in
discrete-rate link adaptation: Is a zero information outage constraint optimal
or not?,
in Proc. 14th European Wireless Conference (EW) 2008, Prague,
Czech Republic, June 2008. Best Paper Award.
19.
B.
Mercier,
V. Fodor, R. Thobaben, M. Skoglund, V. Koivunen, S. Lindfors, J. Ryynnen, E.
G. Larsson, C. Petrioli, G. Bongiovanni, O. Grndalen, K. Kansanen, T. Ekman, G.
E. ien,
A. M. Hayar, R. Knopp, and B. B. Lozano, Sensor networks for cognitive radio:
Theory and system design, in Proc. ICT Mobile Summit
2008,
Stockholm, Sweden, June 2008.
20. C.-S. Chen,
M. Kaynia, G. E. ien, and A. Gjendemsj, Cooperative multi-cell
power control under imperfect channel knowledge: A comparative study, in Proc. 2nd
COST2100 Workshop on MIMO and Cooperative Communications, Trondheim,
Norway, June 2008.
21. M. Haddad, A.
M. Hayar, G. E. ien, and S. G. Kiani, Uplink distributed binary
power allocation for cognitive radio networks, in Proc. CROWNCOM
2008,
Singapore, May 2008.
22. G. E. ien, Cross-layer optimization of wireless sensor
networks for spectrum sensing applications, in VERDIKT Conference Abstract
Book 2008, Bergen, Norway, October 2008 (abstract and oral
presentation only).
23. M. Kaynia and G.
E. ien, Understanding and improving the
performance of MAC protocols in wireless ad hoc networks, in VERDIKT
Conference Abstract Book 2008, Bergen, Norway, October 2008
(abstract, poster, and oral presentation).
24. J. Rasool and G.
E. ien, Multiuser MIMO based airport,
in VERDIKT Conference Abstract Book 2008, Bergen, Norway, October
2008 (abstract and poster only).
25. C. Wang, L. Yin
and G. E. ien, Energy-efficient
adaptive route configuration for MPSK-based wireless sensor networks, in VERDIKT
Conference Abstract Book 2008, Bergen, Norway, October 2008
(abstract and poster only).
2007:
1.
V. Hassel, G. E. ien, and D. Gesbert, Throughput
Guarantees for Wireless Networks with Opportunistic Scheduling: A Comparative
Study, IEEE Transactions on Wireless Communications, vol. 6, no.
12, pp. 4215 – 4220, December 2007.
2. A. Svensson, G.
E. ien,
M.-S. Alouini, and S. Sampei, Scanning The Issue: Special Issue on Adaptive
Modulation and Transmission in Wireless Systems, Proceedings of the
IEEE (guest editorial), vol.
95, no. 12, pp. 2269 – 2273, December 2007.
3. D. Gesbert,
A. Gjendemsj, S. G. Kiani, and G. E. ien, Adaptation,
Coordination, and Distributed Resource Allocation in Interference-Limited
Wireless Networks, Proceedings of the IEEE (invited
paper), vol. 95, no. 12, pp. 2393 – 2409, December 2007.
4.
F. Bhagen, P. Orten, and G. E. ien, Optimal
Design of Uniform Rectangular Antenna Arrays for Strong Line-of-Sight Channels,
EURASIP Journal on Wireless Communications and Networking – Special
Issue on Smart Antennas for Next-Generation Wireless Systems, vol. 2007, Article ID 45084, 10 pages, 2007. DOI:
10.1155/2007/45084.
5. V. Hassel,
M.-S. Alouini, D. Gesbert, and G. E. ien, A Threshold-Based
Channel State Feedback Algorithm for Modern Cellular Systems, IEEE
Transactions on Wireless Communications, vol. 6, no. 7, pp.
2422 – 2426, July 2007.
6. B. Holter and
G. E. ien, Impact of Spatial Correlation on Adaptive Coded
Modulation Performance in Rayleigh Fading, IEEE Transactions on Vehicular
Technology,
vol. 56, no. 3, pp. 1176-1186, May 2007.
7. F. Bhagen,
P. Orten, and G. E. ien, Design of Capacity-Optimal High-Rank
Line-of-Sight MIMO Channels, IEEE Transactions on Wireless Communications, vol. 6, no.
4, pp. 1420-1425, April 2007.
8. D. V. Duong
and G. E. ien, Optimal
Pilot Spacing and Power in Rate-Adaptive MIMO Diversity Systems with Imperfect
CSI, IEEE Transactions on Wireless Communications, vol. 6, no.
3, pp. 845-851, March 2007.
9. A.
Gjendemsj, H.-C. Yang, G. E. ien, and M.-S. Alouini,
Joint adaptive modulation, diversity combining, and power control for downlink
transmission in two-cell wireless networks, in Proc. Asilomar
Conference on Signals, Systems, and Computers 2007, Pacific Grove, USA,
November 2007 (invited).
10. V. Hassel, S.
de la Kethulle de Ryhove, and G. E. ien, Wireless scheduling
algorithms for increased throughput guarantees in wireless networks, in Proc. IEEE ISWCS
2007,
Trondheim, Norway, October 2007.
11. A.
Gjendemsj, H.-C. Yang, M.-S. Alouini, and G. E. ien, Joint
adaptive modulation, diversity combining, and power control for uplink
transmission in two-cell wireless networks, in Proc. IEEE
ISWCS 2007,
Trondheim, Norway, October 2007.
12. E. Krogsveen,
C. Wang, G. E. ien, and S. Lindfors, Energy-efficient adaptive
route configuration in short-range wireless ad-hoc networks, in Proc. IEEE
ISWCS 2007,
Trondheim, Norway, October 2007.
13. L. Yin, C.
Wang, and G. E. ien, Energy consumption optimization in data
transmission from correlated sensor nodes, in Proc. IEEE
ISWCS 2007,
Trondheim, Norway, October 2007.
14. A. Havashki,
P. G. Kjeldsberg, G. E. ien, L. Lundheim, and J. T. Nymoen, On the
impact of fixed point DSP implementation on required channel estimator
complexity in communication receivers, in Proc. IEEE ISWCS 2007, Trondheim,
Norway, October 2007.
15. A. Gjendemsj,
G. E. ien, and D. Gesbert, Binary power
control for multi-cell capacity maximization, in Proc. IEEE
SPAWC 2007,
Helsinki, Finland, June 2007.
16. F. Hekland, G.
E. ien,
and T. A. Ramstad, Quantifying
performance losses in source-channel coding, in Proc. 13th
European Wireless Conference (EW-2007), Paris, France, April
2007.
17. S. G. Kiani, G.
E. ien,
and D. Gesbert, Maximizing multi-cell capacity using distributed power
allocation and scheduling, in Proc. IEEE WCNC 2007, Hong Kong, China, March 2007.
18. S. de la
Kethulle de Ryhove and G. E. ien, Rate-optimal
power adaptation in peak and average power constrained fading channels, in
Proc.
IEEE WCNC 2007, Hong Kong, China, March 2007.
19. A.
Gjendemsj, H.-C. Yang, G. E. ien, and M.-S. Alouini,
Minimum selection GSC with adaptive modulation and post-combining power
control, in Proc. IEEE WCNC 2007, Hong Kong, China,
March 2007.
20. A.
Gjendemsj, S. de la Kethulle de Ryhove, and G. E. ien, A cross-layer comparison of two design philosophies for discrete-rate
adaptive transmission, Temporary Document TD(07)312, 3rd
MCM, COST Action 2100 Pervasive Mobile and Ambient Wireless Communications, Duisburg,
Germany, September 10 - 12, 2007.
21. A.
Gjendemsj, D. Gesbert, G. E. ien, and S. G. Kiani,
Binary power control for multi-link capacity maximization, Temporary Document
TD(07)018, 2nd MCM, COST Action 2100 Pervasive Mobile and Ambient
Wireless Communications, Lisbon, Portugal, February 26 – 28,
2007.
22. F. Bhagen,
P. Orten, and G. E. ien, Design of capacity-optimal high-rank, line-of-sight
MIMO channels, Research Report, Department of Informatics, University of Oslo,
February 2007. Available from http://www.digbib.uio.no/ .
23. F. Bhagen,
P. Orten, and G. E. ien, Modeling and analysis of a 40 GHz MIMO system
for fixed wireless access, Research Report, Department of Informatics,
University of Oslo, February 2007. Available from http://www.digbib.uio.no/ .
2006:
1. G. E. ien
and
T. Javornik (eds.), Rate-adaptive systems and link adaptation, Section
3.6 (pp. 90 – 107) in Chapter 3 Signal Processing of L.
Correia (ed.): Mobile Broadband Multimedia Networks: Techniques, Models and
Tools for 4G. Elsevier Press, ISBN 0-12-369422-1, April 28, 2006.
2. V. Hassel, M.-S. Alouini, G. E. ien,
and D. Gesbert, Rate-Optimal
Multiuser Scheduling with Reduced Feedback Load and Analysis of Delay Effects,
in EURASIP Journal on Wireless Communications and Networking – Special
Issue on Radio Resource Management in 3G+ Systems,
vol. 2006, Article ID 36424, 7 pages, 2006. DOI:10.1155/WCN/2006/36424.
3. D. V. Duong, G.
E. ien,
and K. J. Hole, Adaptive
Coded Modulation with Receive Antenna Diversity and Imperfect Channel Knowledge
at Receiver and Transmitter, in IEEE Transactions on Vehicular
Technology,
vol. 55, no. 2, pp. 458 – 465, March 2006.
4. V. Hassel, G.
E. ien,
and D. Gesbert, Throughput guarantees for wireless networks with opportunistic
scheduling, in Proc. IEEE Globecom 2006, San Francisco, USA,
November 2006.
5. F. Bhagen,
P. Orten, and G. E. ien, On spherical vs. plane wave modelling of
line-of-sight MIMO channels, in Proc. IEEE Globecom 2006, San
Francisco, USA, November 2006.
6. B. Holter and
G. E. ien, Performance
analysis of a rate-adaptive dual-branch switched diversity system, in Proc.
IEEE VTC Fall 2006, Montreal, Canada, September 2006.
7. D. V. Duong,
B. Holter, and G. E. ien, Optimization
and performance analysis of SIMO systems with adaptive coded modulation in
spatially correlated Rayleigh fading, in Proc. IEEE VTC Fall 2006, Montreal,
Canada, September 2006.
8. F. Bhagen,
P. Orten, and G. E. ien, Modeling of line-of-sight 2x2 MIMO channels:
Spherical versus plane waves, in Proc. IEEE PIMRC 2006, Helsinki,
Finland, September 2006.
9. V. Hassel, G.
E. ien,
and D. Gesbert, Throughput guarantees for different opportunistic scheduling
algorithms: A comparative study, in Proc. International Telecommunications
Symposium (ITS) 2006, Fortaleza, Brazil, September 2006.
10. B. Holter and
G. E. ien, Impact of
spatial correlation on adaptive coded modulation performance in Rayleigh fading,
in Proc. International Telecommunications Symposium (ITS) 2006, Fortaleza,
Brazil, September 2006.
11. S. G. Kiani,
D. Gesbert, J. E. Kirkeb, A. Gjendemsj, and G. E. ien, A simple greedy
scheme for multi-cell capacity maximization, in Proc. International Telecommunications Symposium
(ITS-2006), Fortaleza, Brazil, September 2006.
12. F. Bhagen,
P. Orten, and G. E. ien, Optimal design of uniform planar antenna
arrays for strong line-of-sight MIMO channels, in Proc. IEEE
SPAWC 2006,
Cannes, France, July 2006.
13. S. de la
Kethulle de Ryhove and G. E. ien, Capacity-achieving
input phase distributions for noncoherent Rayleigh fading channels with memory,
in Proc. IEEE SPAWC 2006, Cannes, France, July
2006.
14. A.
Gjendemsj, H.-C. Yang, M.-S. Alouini, and G. E. ien, Joint adaptive
transmission and combining with optimized rate and power allocation, in Proc. IEEE
SPAWC 2006,
Cannes, France, July 2006.
15. S. de la
Kethulle de Ryhove and G. E. ien, Maximising the
average spectral efficiency of dual-branch MIMO communication systems with
discrete rate adaptation, in Proc. IEEE SPAWC 2006, Cannes,
France, July 2006.
16. A.
Gjendemsj, G. E. ien, and P. Orten, Optimal
discrete power control for adaptive coded modulation schemes with
capacity-approaching component codes, in Proc. IEEE ICC
2006,
Istanbul, Turkey, June 2006.
17. V. Hassel, M.
R. Hanssen, and G. E. ien, Spectral
efficiency and fairness for opportunistic round robin scheduling, in Proc. IEEE ICC
2006,
Istanbul, Turkey, June 2006.
18. S. de la
Kethulle de Ryhove and G. E. ien, A design
methodology for link adaptation schemes using constellations of constant PAPR,
in Proc. IEEE ICC 2006, Istanbul, Turkey, June
2006.
19. A. Gjendemsj,
D. Gesbert, G. E. ien, and S. G. Kiani, Optimal power
allocation and scheduling for two-cell capacity maximization, in Proc. RAWNET
2006 (2nd WiOpt Workshop on Resource Allocation in Wireless
NETworks),
Boston, USA, April 2006.
20. V. Hassel, H.
Koubaa, and G. E. ien, Feedback protocols for increased multiuser
diversity gain in cellular ALOHA-based networks – A comparative study,
Technical Report, Norwegian University of Science and Technology, Trondheim,
Norway, Nov. 2006.
2005:
1. B. Holter and
G. E. ien, On the
Amount of Fading in MIMO Diversity Systems, IEEE Transactions on
Wireless Communications, vol. 4, no. 5, pp. 2498 – 2507, Sept. 2005.
2. A.
Gjendemsj, G. E. ien, and H. Holm, Optimal power
control for discrete-rate link adaptation schemes with capacity-approaching
coding, in Proc. IEEE Globecom 2005, St. Louis, Missouri,
USA, November 2005.
3. D. V. Duong, G.
E. ien,
and K. J. Hole, Adaptive
trellis-coded modulation with receive antenna diversity and imperfect channel
knowledge at both receiver and transmitter, in Proc. EUSIPCO-2005, Antalya,
Turkey, September 2005.
4. V. Hassel,
M.-S. Alouini, G. E. ien, and D. Gesbert, Rate-optimal
multiuser scheduling with reduced feedback load and analysis of delay effects,
in Proc. EUSIPCO-2005, Antalya, Turkey, September 2005.
5. H. Koubaa, V.
Hassel, and G. E. ien, Contention-less
feedback for multi-user diversity scheduling, in Proc. IEEE VTC Fall
2005,
Dallas, Texas, USA, September 2005.
6. D. V. Duong,
B. Holter, and G. E. ien, Optimal
pilot spacing and power in rate-adaptive MIMO diversity systems with imperfect
transmitter CSI, in Proc. IEEE SPAWC-2005, New York, USA, June
2005.
7. F. Bhagen,
P. Orten, and G. E. ien, On the
Shannon capacity of dual MIMO systems in Ricean fading, in Proc. IEEE
SPAWC-2005,
New York City, USA, June 2005.
8. H. Koubaa, V.
Hassel, and G. E. ien, Multiuser
diversity gain enhancement by guard time reduction, in Proc. IEEE SPAWC-2005, New York
City, USA, June 2005.
9. V. Hassel,
M.-S. Alouini, D. Gesbert, and G. E. ien, Exploiting
multiuser diversity using multiple feedback thresholds, in Proc. IEEE VTC Spring
2005,
May/June 2005.
10. F. Bhagen,
P. Orten, and G. E. ien, Modeling
and analysis of a 40 GHz MIMO system for fixed wireless access, in Proc. IEEE VTC
Spring 2005, Stockholm, Sweden, May/June 2005.
11. S. de la
Kethulle de Ryhove, G. E. ien, and F. Bhagen, Subchannel SNR
distributions in dual-branch MIMO systems, in Proc. IEEE/ITG
International Workshop on Smart Antennas, Duisburg, Germany,
April 2005.
12. F. Hekland, G.
E. ien,
and T. A. Ramstad, Using
2:1 Shannon mapping for joint source-channel coding, in Proc. Data
Compression Conference 2005, Snowbird, Utah, USA, March 2005.
13. F. Bhagen,
P. Orten, and G. E. ien, Construction
and capacity analysis of high-rank line-of-sight MIMO channels, in Proc. IEEE
WCNC-2005,
New Orleans, LA, USA, March 2005.
14. D. V. Duong,
M. . Wingar, and G. E. ien, Link
adaptation in correlated antenna diversity environments, in Proc. Norwegian
Signal Processing Symposium (NORSIG) 2005, Stavanger, Norway,
September 2005.
15. S. de la
Kethulle de Ryhove and G. E. ien. Energy-optimised
coded modulation for short-range wireless communications on Nakagami-m fading
channels,
in
Proc. Norwegian Signal Processing Symposium (NORSIG) 2005, Stavanger,
Norway, September 2005.
16. H. Koubaa, V.
Hassel, and G. E. ien, Multiuser diversity gain enhancement by guard
time reduction, Temporary Document no. TD(05)-038, 12th Management
Committee Meeting, COST Action 273 Towards Mobile Multimedia Broadband
Networks,
Bologna, Italy, January 20 – 21, 2005.
17. D. V. Duong, G.
E. ien,
and K. J. Hole, Adaptive trellis-coded modulation with receive antenna
diversity and imperfect channel knowledge at both receiver and transmitter,
Temporary Document TD(05)-009, 12th Management Committee Meeting,
COST Action 273 Towards Mobile Multimedia Broadband Networks, Bologna,
Italy, January 20 – 21, 2005.
2004:
1. G. E. ien, Radio
interface and access technologies for mobile and wireless systems beyond 3G,
invited paper in Telektronikk vol. 100, no. 3, pp. 55 – 68,
November 2004.
2. G. E. ien, H. Holm,
and K. J. Hole, Impact
of Channel Prediction on Adaptive Coded Modulation Performance in Rayleigh
Fading, in IEEE Transactions on Vehicular Technology, vol. 53,
no.3, pp. 758 – 769, May 2004.
3. B. Holter,
M.-S. Alouini, G. E. ien, and H.-C. Yang, Multiuser
switched diversity transmission, in Proc. IEEE VTC
Fall 2004, Los Angeles, CA, USA, September 2004.
4. O. Jetlund, G.
E. ien,
H. Holm, and K. J. Hole, Spectral
efficiency bounds for adaptive coded modulation with outage probability
constraints and imperfect channel prediction, in Proc. Nordic Radio
Symposium 2004, Oulu, Finland, August 2004.
5. D. V. Duong
and G. E. ien, Adaptive coded modulation with imperfect
channel state information at the receiver and transmitter, in Proc. Nordic
Radio Symposium 2004, Oulu, Finland, August 2004.
6. G. E. ien, N. Holte,
S. Andresen, T. Svendsen, and M. Hammer, Communication technology towards
2020. Position paper, The Faculty of Information Technology, Mathematics, and
Electrical Engineering, NTNU, Spring 2004. In Proc. INFOSAM-2020 conference,
NTNU, April 19th – 20th, 2004. 6 pages.
7. O. Jetlund, G.
E. ien,
and H. Holm, Switching thresholds for robust adaptive coded modulation with
predicted channel state information: A step towards an analytical solution,
Temporary Document no. TD(04)-34, 9th MCM Meeting, COST Action 273 Towards
Mobile Multimedia Broadband Networks, Athens, Greece,
January 26 - 28, 2004. 12 pages.
2003:
1. F. Bhagen, G.
E. ien,
M.-S. Alouini, and K. J. Hole, Bounds
on average area spectral efficiency for adaptive coded modulation in cellular
networks, in Proc. 6th Baiona Workshop on Signal Processing
in Communications, Baiona, Spain, September 8-10, 2003.
2. M. Kang,
M.-S. Alouini, and G. E. ien, How accurate
are the Gaussian and Gamma approximations to the outage capacity of MIMO
channels?, in Proc. 6th Baiona Workshop on
Signal Processing in Communications, Baiona, Spain, September
8-10, 2003.
3. H. Holm, G.
E. ien,
M.-S. Alouini, D. Gesbert, and K. J. Hole, Optimal design
of adaptive coded modulation schemes for maximum average spectral efficiency,
in Proc. IEEE Workshop on Signal Processing Advances in Wireless
Communications 2003 (SPAWC-2003), Rome, Italy, June 15-18, 2003.
4. L. Yang,
M.-S. Alouini, and G. E. ien, Performance
of buffered adaptive transmission, in Proc. COST 273
Workshop on Broadband Wireless Local Access, pp. 15/1 – 15/6,
Paris, France, May 21-22, 2003.
5. B. Holter, G.
E. ien, K.
J. Hole, and H. Holm, Limitations
in spectral efficiency of a rate-adaptive MIMO system utilizing pilot-aided
channel prediction, in Proc. IEEE Vehicular Technology Conference
Spring 2003 (VTC Spring 2003), Jeju Island, Korea, April 2003.
6. O. Jetlund, G.
E. ien,
K. J. Hole, and B. Holter, Adaptive
Gallager coded modulation scheme on Rayleigh fading channels: Comparison of
simulated and theoretical performance, in Proc. Norwegian Signal
Processing Symposium 2003 (NORSIG-03), Bergen, Norway,
October 2003.
7. O. Jetlund, G.
E. ien,
B. Holter, and K. J. Hole, Optimal Channel Prediction in an Adaptive Gallager
Coded Modulation Scheme on Rayleigh Fading Channels, Temporary Document no.
TD(03)-127, 7th MCM Meeting, COST Action 273 Towards Mobile
Multimedia Broadband Networks, Paris, France, May 21 - 23, 2003. 18 pages.
8. O. Jetlund, G.
E. ien,
and K. J. Hole, Adaptive Gallager coded modulation on Rayleigh fading
channels: Comparison of simulated and theoretical performance, Temporary
Document no. TD(03)-040, 6th MCM Meeting, COST Action 273 Towards
Mobile Multimedia Broadband Networks, Barcelona, Spain,
January 15 - 17, 2003. 12 pages.
2002:
1. G. E. ien,
Information theory: The foundation of modern telecommunications, in Telektronikk vol. 98, no.
1, pp. 3 – 19, July 2002.
2. K. J. Hole,
H. Holm, and G. E. ien, Performance
analysis of adaptive coded modulation with antenna diversity and feedback delay,
in Telektronikk vol. 98, no. 1, pp. 106 – 113, July 2002.
3. K. J. Hole, G.
E. ien, and
H. Holm, Adaptive
coded modulation for wireless OFDM channels: Upper bounds on average spectral
efficiency and influence of imperfect channel knowledge, in Proc. IEE
Conference on Getting the Most out of the radio Spectrum, London, UK,
October 4-7, 2002.
4. G. E. ien, R. K.
Hansen, D. V. Duong, H. Holm, and K. J. Hole, Bit error
rate analysis of adaptive coded modulation with mismatched and
complexity-limited channel prediction, in Proc. 5th IEEE Nordic Signal Processing Symposium,
Hurtigruten, Norway, October 2002.
5. B. Holter and
G. E. ien, The
optimal weights of a maximum ratio combiner using an eigenfilter approach,
in Proc. 5th IEEE
Nordic Signal Processing Symposium, Hurtigruten, Norway, October 2002.
6. G. E. ien, H. Holm,
and K. J. Hole, Adaptive
coded modulation with imperfect channel state information: System design and
performance analysis aspects, invited paper (extended 2-page abstract) in
Proc. IEEE International Symposium on Advances in Wireless Communications, Victoria,
Canada, September 2002.
7. G. E. ien, H. Holm and
K. J. Hole, Channel
prediction for adaptive coded modulation in Rayleigh fading, in Proc. EURASIP
European Signal Processing Conference (EUSIPCO-2002), Toulouse,
France, September 2002.
8. B. Myhre, V.
Markhus and G. E. ien, LPDC-coded
adaptive modulation on slowly varying Nakagami-fading channels, in Proc. European
Wireless 2002, pp. 822 - 828, Florence, Italy, February, 2002.
9. G. E. ien, K. J. Hole,
N. Holte, T. A. Ramstad, and B. Holter, Bandwidth-efficient
and adaptive transmission schemes for wireless multimedia communications,
invited paper in Proc. 2nd International Workshop on Research Directions in
Mobile Communications and Services, Grimstad, Norway, September 2002.
10. O. Jetlund, G.
E. ien,
K. J. Hole, V. Markhus, and B. Myhre, Rate-adaptive coding and modulation with
LDPC component codes, Temporary Document no. TD(02)-108, 5th MCM
Meeting, COST Action 273 Towards Mobile Multimedia Broadband Networks, Lisbon,
Portugal, September, 2002. 15 pages.
11. G. E. ien, H. Holm,
and K. J. Hole, Adaptive coded modulation enhanced by channel prediction and
antenna diversity, Temporary Document no. TD(02)-054, 4th MCM
Meeting, COST Action 273 Towards Mobile Multimedia Broadband Networks, Espoo,
Finland, May, 2002. 17 pages.
12. G. E.
ien, Informasjonsteori,
koding og kompresjon. Lecture notes for siv.ing. course SIE2035
Information theory, coding, and compression, TAPIR
Kompendieforlaget. 3rd ed., August 2002. 192 pages (partly in
Norwegian).
2001:
1. K. J. Hole
and G. E. ien, Spectral
Efficiency of Adaptive Coded Modulation in Urban Microcellular Networks, IEEE
Transactions on Vehicular Technology, vol. 50, no. 1, pp.
205-222, Jan. 2001.
2. K. J. Hole
and G. E. ien, Adaptive
channel coding and modulation: A key to bandwidth-efficient multimedia
communications in future wireless systems. Invited paper, Telektronikk
(special issue on Wireless Future) vol. 97, no. 1, pp. 49
– 57, May 2001.
3. K. J. Hole,
H. Holm, and G. E. ien, Analysis
of adaptive coded modulation with antenna diversity and feedback delay, in
Proc. IST Mobile Communications Summit 2001, pp. 865-870, Sitges,
Spain, September 2001.
4. K. J. Hole, G.
E. ien, B.
Rislw, and P. Orten, Rate-adaptive modulation and coding in fixed Ka-band
satellite communications: A feasibility study, in Proc. Nordic Radio
Symposium 2001 (NRS-01), Nynshamn, Sweden, April 2001.
5. G. E. ien
and
K. J. Hole, Maximum
average spectral efficiency for slowly varying Rayleigh fading channels with
pilot-symbol-assisted channel estimation, in Proc. 4th
European Personal Mobile Communications Conference (EPMCC-2001), Wien,
Austria, February 2001. CD-ROM proceedings only.
6. B. Myhre, V.
Markhus, and G. E. ien, LDPC
coded adaptive multilevel modulation for slowly varying Rayleigh-fading
channels, in Proc. Norwegian Signal Processing Symposium 2001
(NORSIG-01), Trondheim, Norway, October 2001.
7. G. E. ien and T. A.
Ramstad, On
the role of Wiener filtering in quantization and DPCM, in Proc. Norwegian
Signal Processing Symposium 2001 (NORSIG-01), Trondheim, Norway,
October 2001.
2000:
1. K. J. Hole,
H. Holm, and G. E. ien, Adaptive Multidimensional Coded Modulation
for Flat Fading Channels, IEEE Journal on Selected Areas in Communications,
vol.
18, no. 7, pp. 1153-1158, July 2000.
2. G. E. ien
and
N. Holte, Digital kommunikasjon. Lecture notes for
external course Digital Communications, Dept. of
Telecommunications, NTNU, August 2000 (partly in Norwegian).
1999:
1. H. Holm, K.
J. Hole, and G. E. ien, Spectral efficiency of variable-rate coded QAM
for flat fading channels, in Proc. NORSIG-99, Asker, Norway, pp. 130
– 135, September 1999.
2. J. Noll,
P.-H. Lehne, G. E. ien, A. Perkis, K. Grythe, L. Lundheim, and N.
Stol, Research and development of a UMTS demonstrator in Norway, BT Alliance
Engineering Symposium 1999, Oslo, June 1999.
3. G. E.
ien, Introduction
to channel
coding. Additional lecture notes for siv. ing. course 42521 Information and
Coding Theory, Dept. of Telecommunications, NTNU, Fall 1999.
4. G. E. ien and T.A.
Myrvoll, Informasjonsteori og feilkorrigerende koding, Del 1:
Informasjonsteori. Lecture notes for siv.ing. course 42521 Information
and Coding Theory, Department of Telecommunications, NTNU. 2nd
ed., August 1999. 119 pages (in Norwegian).
5. G. E.
ien, Source
and channel coding, chapter 4 in lecture notes for annual ATHENS-organized
intensive course on Digital Signal Processing in Telecommunications Systems (ed. Tor A.
Ramstad, various authors), Dept. of Telecommunications, NTNU, 1999. 51 pages.
1998:
1. G. E. ien and S.
Lepsy, On the benefits of basis orthogonalization in fractal compression, in
Y. Fisher (ed.): Fractal Image Encoding and Analysis, pp. 65 - 88.
Springer Verlag, ISBN 3-540-63196-8, March 1998.
2. G. E. ien and G.
Nrstad, Fractal compression of ECG signals, in Y. Fisher (ed.): Fractal
Image Encoding and Analysis, pp. 201 - 226. Springer Verlag, ISBN
3-540-63196-8, March 1998.
3. S. Lepsy, P.
Carlini, and G. E. ien, On fractal compression and vector
quantization, in Y. Fisher (ed.): Fractal Image Encoding and Analysis, pp. 21 - 48.
Springer Verlag, ISBN 3-540-63196-8, March 1998.
4. I.
Balasingham, T. Ramstad, M. Adams, F. Kossentini, H. Coward, A. Perkis and G.
E. ien,
Performance evaluation of different filter banks in the JPEG-2000 baseline
system, in Proc. ICIP-98 (IEEE International Conference of Image
Processing), Chicago, USA,
October 1998.
5. A. Perkis, H.
Coward, T. Ramstad, G. E. ien, and I. Balasingham, JPEG2000 in mobile
and wireless communications, in Proc. 3rd ACTS Mobile Summit, Rhodos,
Greece, June 1998.
6. H. Coward, A.
Perkis, T. Ramstad, G. E. ien, and I. Balasingham, Robustness against
channel errors in JPEG2000, in Proc. 3rd IEEE Nordic Signal
Processing Symposium (NORSIG-98), Lyngby, Denmark, June 1998.
7. A. Perkis, G.
E. ien,
T. A. Ramstad, and T. Halbach, Fixed Length Coding by Nonuniform Scalar
Quantization in JPEG2000, ISO/IEC JTC 1/SC 29/WG 1 Document no. N 851. July
1998.
8. A. Perkis, G.
E. ien,
and T. A. Ramstad, Impact of Fixed Length Coding (FLC) versus Variable Length
Coding (VLC) in JPEG2000, ISO/IEC JTC 1/SC 29/WG 1 Document no. N 738. March
1998.
9. H. Coward, T.
A. Ramstad, G. E. ien, and A. Perkis, Multilevel Signaling, ISO/IEC
JTC 1/SC 29/WG 1 Document no. N 739. March 1998.
10. I.
Balasingham, T. A. Ramstad, A. Perkis, and G. E. ien,
Performance of Different Filter Banks and Wavelet Transforms, ISO/IEC JTC
1/SC 29/WG 1 Document no. N 740. March 1998.
1997:
1. G. E. ien,
Information theory: The foundation of modern communications, in Proc. NORSIG-97, Troms,
Norway, May 1997.
1996:
1. G. E. ien, H.
Krkeland, and G. Nrstad, Fast fractal-based ECG signal compression, in
Proc. IEEE International Conference on Engineering in Medicine and Biology, Amsterdam,
Holland, October 1996.
2. G. E. ien, R.
Hamzaoui, and D. Saupe, On the limitations of fractal image texture coding,
Proc. 2nd IEEE Nordic Signal Processing Symposium (NORSIG-96), Espoo,
Finland, September 1996.
3. G. E. ien, N. A. Bertelsen,
T. Eftestl, and J. H. Husy, ECG rhythm classification using artificial
neural networks, in Proc. IEEE DSP Workshop, Loen, Norway,
September 1996.
4. G. E. ien and A.
Lvendahl, Vector quantization of ECG signals, in Proc. International
Symposium on Digital Signal Processing, London, UK, July 1996.
5.
. Eriksen, H. Heimvoll, P. A. Linnerud, and G. E. ien, Digital
signal processing: Processors and tools, EKF-rapport EKF R-98, techn. rep.,
Elektronikkindustriens Konstruksjonsforum (EKF), 1996. 216 pages (in
Norwegian).
1995:
1. G. E. ien and S.
Lepsy, A class of fractal image coders with fast decoder convergence. in Y.
Fisher (ed.): Fractal Image Compression: Theory and Applications (Springer
Verlag), pp. 157 - 179, January 1995.
2. S. Lepsy and
G. E. ien, Fast attractor image encoding by adaptive codebook
clustering. in Y. Fisher (ed.): Fractal Image Compression: Theory and
Applications (Springer Verlag), pp. 181 - 201, January 1995.
3. G. E. ien and P.
Osnes, Diabetic retinopathy: Automatic detection of early symptoms from
digital retinal images, in Proc. NORSIG-95, Stavanger, Norway,
September 1995.
1994:
1. G. E. ien and S.
Lepsy, Fractal-Based Image Coding with Fast Decoder Convergence, Signal
Processing,
vol. 40, pp. 105-117, 1994.
2. G. E. ien, Parameter
quantization in fractal image coding, in Proc. IEEE ICIP-94 (1st IEEE
International Conference on Image Processing), USA, November 1994.
3. G. E. ien and S.
Lepsy, Analysis of a complexity reduction algorithm in fractal image coding,
in Proc. ICSPAT-94 (5th International Conference on Signal Processing
Applications and Technology), pp. 910-915, Dallas, USA, October 1994.
4. G. E. ien, Z. Baharav,
S. Lepsy, E. Karnin, and D. Malah, A new improved collage theorem with
applications to multiresolution fractal image coding, in Proc. IEEE ICASSP-94 (IEEE International
Conference on Acoustics, Speech and Signal Processing), vol. 5, pp.
565-568, May 1994.
5. G. E. ien, Parameter
quantization in fractal image coding, in Proc. 1st IEEE Nordic
Signal Processing Symposium (NORSIG-94), pp. 252-257, lesund,
Norway, June 1994.
1993:
1. G. E. ien and S.
Lepsy, Improving the decoder in a fractal image compression method, in Proc.
COST No. 229 WG.1+2 2nd Vigo Workshop on Adaptive Methods and Emergent
Techniques for Signal Processing and Communications, pp. 326 – 334,
Bayona, Spain, June 1993.
2. S. Lepsy, G.
E. ien,
and T. A. Ramstad, Attractor image compression with a fast noniterative
decoding algorithm, in Proc. IEEE ICASSP-93, pp. V-337 - V-340,
Minneapolis, USA, April 1993.
3. P. Waldemar, G.
E. ien,
and T. A. Ramstad, Fast image coding by nonlinear contractive
transformations, in Proc. IEEE Winter Workshop on Nonlinear Digital Signal
Processing,
p. 13.1, Tampere, Finland, January 1993.
4. G. E. ien, S. Lepsy,
and T. A. Ramstad, Fractal-based image compression: Status report 1993, in
Proc. NORSIG-93, Lillehammer, Norway, February 1993 (in
Norwegian).
5. G. E. ien, L2-Optimal
Attractor Image Coding with Fast Decoder Convergence. Dr. ing. thesis, NTH,
April 1993. Supervisor: Prof. Tor A.
Ramstad.
1992:
1. G. E. ien, S. Lepsy,
and T. A. Ramstad, Reducing the complexity of a fractal-based image coder, in
Proc. EUSIPCO-92 (The European Signal Processing Conference), pp.
1353-1356, Brussels, Belgium, August 1992.
2. S. Lepsy og G.
E. ien,
Attractor image compression featuring direct attractor optimization and
noniterative decoding, in Proc. Norwegian Conference on Industrial
Mathematics (INDUMAT-92), Trondheim, Norway, August 1992.
3. G. E. ien, A. Sollid,
and T. A. Ramstad, Hybrid image compression combining attractor coding and
transform coding, in Proc. Norwegian Image Compression Conference
(NOBIM-92),
pp. 286-293, Trondheim, Norway, 1992.
1991:
1. G. E. ien, S. Lepsy,
and T. A. Ramstad, An inner product space approach to image coding by
contractive transformations, in Proc. IEEE ICASSP-91, pp.
2773-2776, Toronto, Canada, May 1991.
1989:
1. G. E. ien, Automatic
voice recognition: Theoretical foundations and signal processor implementation
of a vector quantization based algorithm. MScEE thesis, NTH, April 1989 (in
Norwegian).