july 2009 doc.: ieee 802.11-09/0823r0 submission progress report for corridor channel model for tgac...
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July 2009 doc.: IEEE 802.11-09/0823r0
Submission
Progress Reportfor Corridor Channel Model
for TGac
Byung-Jae Kwak et al., ETRISlide 1
Name Affiliations
Address Phone E-mail
Byung-Jae Kwak ETRI 138 Gajeongno, Yuseong-gu, Daejeon, 305-700, Korea
+82-42-860-6618
Myung Don Kim ETRI 138 Gajeongno, Yuseong-gu, Daejeon, 305-700, Korea
+82-42-860-6178
Jae Joon Park ETRI 138 Gajeongno, Yuseong-gu, Daejeon, 305-700, Korea
+82-42-860-3958
Wonsop Kim ETRI 138 Gajeongno, Yuseong-gu, Daejeon, 305-700, Korea
+82-42-860-5302
Minho Cheong ETRI 138 Gajeongno, Yuseong-gu, Daejeon, 305-700, Korea
+82-42-860-5635
Hyun Kyu Chung ETRI 138 Gajeongno, Yuseong-gu, Daejeon, 305-700, Korea
+82-42-860-6140
July 2009
Submission
doc.: IEEE 802.11-09/0823r0
Contents
• Introduction• Channel Measurement• Analysis of Channel Measurement
– SAGE Algorithm– Clustering
• Discussion
Slide 2 Byung-Jae Kwak et al., ETRI
July 2009
Submission
doc.: IEEE 802.11-09/0823r0
Introduction• During Vancouver Meeting,
– it was found out that MIMO performance degrades significantly in environments such as corridor [1];
– TGac agreed further study of corridor channel is needed after discussion.
• Further study of corridor channel, presented in Montreal Meeting, revealed that the current TGn channel models are inappropriate to model corridor channel [2]
• In Montreal Meeting, IEEE 802.11-09/0308 was adopted as “TGac Channel Model Addendum” baseline document
• IEEE 802.11-09/0308r5, “TGac Channel Model Addendum” [3]:“The scope of this document is limited to extensions of the existing
TGn channel model definitions (i.e., Models A-F). The introduction of a new model definition covering indoor corridor propagation is TBD.”
• This contribution is a status report of the work in progress on Corridor Channel Model
Slide 3 Byung-Jae Kwak et al., ETRI
July 2009
Submission
doc.: IEEE 802.11-09/0823r0
Channel Measurement
• Channel measurement completed with Brand new antenna systems– 8x8 uniform linear antenna systems– 8x8 uniform circular antenna system
(also used for AoD/AoA estimation)
• 3 measurement sites:– 1st fl., Bldg. 1, ETRI– 2nd fl., Bldg. 11, ETRI– 1st fl., dorm. bldg.
Slide 4 Byung-Jae Kwak et al., ETRI
July 2009
Submission
doc.: IEEE 802.11-09/0823r0
Analysis of Channel Measurement
• SAGE: Space-Alternating Generalized Expectation-Maximization Algorithm[4]
• SAGE is widely used for channel estimation[5]
• ETRI has extensive experience of using SAGE for outdoor measurements
• ETRI is currently making some improvements to SAGE implementation for indoor environment: larger number of paths, memory efficiency, speed up, etc
Slide 5 Byung-Jae Kwak et al., ETRI
July 2009
Submission
doc.: IEEE 802.11-09/0823r0
Phase Shift by AoD and AoA
Slide 6 Byung-Jae Kwak et al., ETRI
July 2009
Submission
doc.: IEEE 802.11-09/0823r0
Received Signal Matrix
Slide 7
Received signal matrix for a single path =
Received signal matrixwith multi-path
Byung-Jae Kwak et al., ETRI
July 2009
Submission
doc.: IEEE 802.11-09/0823r0
SAGE Algorithm (1/4)
• EM algorithm:– Stable (eventually approach a stationary point)– Complicated, slow convergence
• SAGE algorithm:– Extends EM by sequentially updating small
groups of elements– Has the same monotonic property as EM
stable– Faster convergence than EM– Significant reduction of complexity
Slide 8 Byung-Jae Kwak et al., ETRI
July 2009
Submission
doc.: IEEE 802.11-09/0823r0
SAGE Algorithm (2/4)
• The objective function
• The objective function has peaks when
Slide 9 Byung-Jae Kwak et al., ETRI
July 2009
Submission
doc.: IEEE 802.11-09/0823r0
SAGE Algorithm (3/4)
• Def:– –
• Iteration:
•
Slide 10 Byung-Jae Kwak et al., ETRI
July 2009
Submission
doc.: IEEE 802.11-09/0823r0
SAGE Algorithm (4/4)
• What do we get from SAGE Alg.:– Delay, delay spread– AoD, AoA, and the respective angular
spread– Doppler, Doppler spread– K-factor– # clusters, etc
• Need to do clustering
Slide 11 Byung-Jae Kwak et al., ETRI
July 2009
Submission
doc.: IEEE 802.11-09/0823r0
-50 0 50 100 150 200 250 300 350 4000
5
10
15
20
25
30
Delay in Nanoseconds
Rel
ativ
e dB
Clustering
• Grouping of received rays for interpretation
Slide 12
(Source: [6] “TGn Channel Models”)
Byung-Jae Kwak et al., ETRI
July 2009
Submission
doc.: IEEE 802.11-09/0823r0
Discussion
• Goal:To propose a Corridor Channel Model in
Sept. meeting• Other parameters can also be
obtained from the measurement data• Comments and suggestions are
welcome
Slide 13 Byung-Jae Kwak et al., ETRI
July 2009
Submission
doc.: IEEE 802.11-09/0823r0
References[1] IEEE 802.11-09/0345r0, “Indoor Channel Measurements for TGac,”
IEEE 802.11 #114, March 2009.[2] IEEE 802.11-09/0542r0, “Channel Measurements in Corridors for
TGac,” IEEE 802.11 #115, May 2009.[3] IEEE 802.11-09/0308r5, “TGac Channel Model Addendum,” IEEE
802.11 #115, May 2009.[4] J. A. Fessler, A. O. Hero, “Space-Alternating Generalized
Expectation-Maximization Algorithm,” IEEE Transactions on Signal Processing, vol. 42, no. 10, pp. 2664-2677, 1994.
[5] Bernard H. Fleury, Martin Tschudin, Ralf Heddergott, Dirk Dahlhaus, Klaus Ingeman Pedersen, “Channel Parameter Estimation in Mobile Radio Environments Using the SAGE Algorithm,” IEEE Journal on Selected Areas in Communications, vol. 17, no. 3, March 1999, pp. 434-450.
[6] IEEE 802.11-03/940r4, “TGn Channel Models,” May 2004.[7] Adel A. M. Saleh, Reinaldo A. Valenzuela, “A Statistical Model for
Indoor Multipath Propagation,” IEEE Journal on Selected Areas in Communications, vol. SAC-5, no. 2, Feb. 1987, pp. 128-137.
Slide 14 Byung-Jae Kwak et al., ETRI