Title: Self-organized Spectrum Chunk Selection Algorithm for Local Area Deployment
1Self-organized Spectrum Chunk Selection
Algorithm for Local AreaDeployment
- Sanjay Kumar 1
- Yuanye Wang 2, Nicola Marchetti 2
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- 1Birla Institute of Technology, Ranchi, India
- skumar_at_bitmesra.ac.in
- 2Aalborg University, Denmark
- ywa _at_es.aau.dk, nm_at_es.aau.dk
2 Contents
- Introduction
- Motivation and Objectives
- Algorithm
- Scenaion Description
- Performance Metrics
- Evaluation Parameters
- Performance Results
- Conclusions
-
3 Introduction
- The IMT-A 4G systems with new capabilities
- To be operational around the year 2015
- Provide access to wide range of telecommunication
services - Target peak data rates 1 Gbps in DL and 500 Mbps
in UL - Focus on Local Area (LA) deployment scenarios
- The Wide Area (WA) deployment uses fixed
frequency reuse schemes - It needs proper network planning, such as
- Frequency reuse plans
- Base station location
- Controlling transmit power levels etc.
- The LA of IMT-A expected random and
uncoordinated deployment - Hence netwrok planning not feasible
- Also, possiblly Home Node Bs (HeNBs) share the
available radio spectrum - A mechanism is needed to assign spectrum in self
organized manner and improve throughput
performance -
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4 Motivation and Objectives
- Reuse 2 gives the highest throughput performance
in LA deployment 11, but needs Network planning - A mechanism is needed to achieve nearly same
performance in random deployment
Fig. 1. Possible chunk selection with reuse 2 in
random deployment
Fig. 2. Allocation for reuse 2 with optimal
network planning
To minimize the mutual inter-cell interference
among HeNBs with random and uncoordinated
deployment in order to improve throughput
performance .
5 Algorithm
- Steps
- Initialization
- Update chunk selection
- Interference consideration
- Chunk switch over
Figure 3 Flow chart of the Algorithm
6 Algorithm Description
Spectral bandwidth is divided in two equal size
spectrum chunks (for considering to compare
with reuse 2) Algorithm could be used for any
reuse schemes
Step 1 Initialization phase
- Random selection of a spectrum chunk
- Initialization with sequence number
switch-over number - Sequence number determines position in queue
- Switch-over number helps to avoid dead lock
situation - It indicates the maximum of times a chunk is
retained
7 Algorithm Description (1)
Step 2 Condition to update the chunk selection
- The sequence number is reduced by one in each
update interval - This indicates HeNB turn to update its chunk
selection
Step 3 Interference consideration for chunk
selection
- Comparison of interference levels over the chunks
- The UL-RIP is used as interference measurement
yard stick - UL- RIP is defined as the total power received
over the spectrum chunk - The chunk selection is based on Abs (RIP1 -
RIP2 ) gt P_Threshold - This ensures a sufficient amount of interference
difference before decision - The threshold indicates a tradeoff between
- tolerable interference vs increased signaling
requirement
8 Algorithm Description (2)
Step 4 Switching over to other Chunk
- The chunk with minimum RIP is chosen
- Main features of the Algorithm
-
- Uses UL- RIP (already standardized for LTE
system) - Works in a random and uncoordinated deployment
- Requires very little signaling exchange
- Chunks allocation in sequence (avoids complexity
in interference assessment) - If of HeNBs is very high a long convergence
time may be required - Provides a scalable solution.
- Performance is upper-bounded by reuses 2 scheme
- Could be used for both DL UL
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9 Scenario Description
Figure 4 LA office indoor with 4 HeNBs
- HeNB Location center of each cell (also
examined with randomized) - HeNB coverage area . 50 x 25 m (consisting of 10
rooms) - Simulation method snap-shot based
- Several thousands snap-shots are simulated
- Users uniformly distributed locations
- Throughput Mapping SINR 8
10 Performance Metrics
- Average Cell Throughput Cell throughput averaged
among all the simulated cells - Cell Edge User Throughput The 5 user outage
throughput , CDF value - Chunk Selection Interval Time period for one
chunk selection operation. -
It contains an integer number of transmission
frames.
- Some simplifications are also assumed
- No power control
- Round Robin for frequency domain scheduling
- Fast fading not considered
11 Simulation Parameters
PARAMETERS SETTINGS Spectrum allocation 100
MHz at 3.5 GHz Access schemes DL OFDMA, UL
SCFDMA Duplexing Schemes TDD UEs per Cell
510 Total Transmit Power 24dBm Receiver
Noise Figure 7-9 dB Room Size 10x10
m Corridoor width 5 m Internal walls light
attenuation (5dB) Shadow fading LOS 3dB,
NLOS 6dB (SD) Path Loss models LOS 18.7 log10
(d) 46.8 20log10 (f /5.0) NLOS 20 log10
(d) 46.4 nw Lw 20log10 (f
/5.0) where, d direct-line distance
(m) f carrier frequency (GHz) nw of
walls between Tx Rx Lw wall attenuation
(dB)
12 Performance Results (1)
DL Average Cell Throughput
- Improved compared to reuse
- 1 and 4 schemes
- Slightly lower compared to
- reuse 2 scheme
- Reuse 2 needs planning for
- optimal performance.
- Proposed algorithm performs in
- self- organized manner with
- random and un-coordinated
- deployment
Figure 5 Comparison of DL Average Cell
Throughput
13 Performance Results
Performance Results (2)
DL Cell Edge User Throughput
- significantly higher
- compared to reuse 1
- scheme (200 300 )
- Nearly same as reuse
- 4 scheme
- However lower than
- reuse 2 scheme
Figure 6 Comparison of DL Cell Edge User
Throughput
14 Performance Results
Performance Results (3)
Convergence Time
The performance is stabilized after 10
selection intervals, with Significant
Improvement
Figure 7 Convergence Time of the Algorithm
15 Performance Results
Performance Results (4)
Randomized HeNB Locations
- It may be difficult to control HeNB locations
- Especially in home scenarios
- Nearly the similar performance is realized
With the same chunk allocation as DL, The similar
performance has been realized in UL also
Figure 8 DL Average Cell Throughput with
Randomized HeNB Locations
16 Conclusions
- An Algorithm for self organized spectrum chunk
selection has been proposed - It minimizes mutual inter-cell interference and
improves the system throughput performance - Performance approaches fixed frequency reuse 2
scheme - Gives much better performance than fixed
frequency 1 and 4 schemes - Suitable for LA with large scale random and
uncoordinated deployment - Works with very limited signaling exchange
- Needs no additional measurements than what is
already established for the LTE - The main features of the algorithm are
scalability and operation simplicity
17 References
- 1 H. Murai, M. Edvardsson and E. Dahlman,
LTE-Advanced The Solution for IMT-Advanced,
ERICSSON, 2008. - 2 IEEE 802.11 B. P. Crow, I. Widjaja, J.G.
Kim, P. T. Sakai, Wireless Local Area Networks,
IEEE Communications Magazine, September 1997, pp.
116-126. - 3 ETSI MCC, Report of 3GPP TSG RAN
IMT-Advanced Workshop, April 7-8, 2008. - 4 Arne Simonsson, Frequency Reuse and
Intercell Interference Co-ordination in E-UTRA,
IEEE VTC2007-Spring, pp. 3091-3095 - 5 R. Giuliano, C. Monti and P. Loreti,
Wireless Technologies Advances for Emergency and
Rural Communications - WiMAX Fractional Frequency
Reuse for Rural Environments, IEEE Wireless
Communications, June 2008, pp. 60-65 - 6 T. S. Rappaport and R. A. Brickhouse, A
Simulation Study of Urban In-building Cellular
Frequency Reuse, IEEE Personal Communications,
February 1997, pp. 19-23 - 7 IST-4-027756 WINNER II, D1.1.2 WINNER II
Channel Models part I- Channel Models, Sept
2007. - 8 P. Mogensen, W. Na, I. Kovács, F.
Frederiksen, A. Pokhariyal, K. Pedersen, T.
Kolding, K. Hugl and M. Kuusela, LTE Capacity
compared to the Shannon Bound, IEEE
VTC2007-Spring, pp. 1234-1238. - 9 TR 101 112 V3.2.0 (1998-04), Technical
Report, Universal Mobile Telecommunications
System (UMTS) Selection Procedures for the
Choice of Radio Transmission Technologies of the
UMTS (UMTS 30.03 version 3.2.0) - 10 3GPP TR 25.814 Technical Specification Group
Radio Access Network Physical Layer Aspects for
Evolved UTRA, V7.0.0 (2006-6). - 11 Sanjay Kumar, Techniques for Efficient
Spectrum Usage for Next Generation Mobile
Communication Networks An LTE and LTE-A case
Study a PhD thesis at Aalborg University,
Denmark, June, 2009 (ISBN 978-87-92328-29-8). -
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