ahmed n. zaki and abraham o. fapojuwo dept. of electrical and computer engineering
DESCRIPTION
A novel radio resource management approach for QoS Provisioning in multi-service Multi-slot OFDMA Systems. Ahmed N. Zaki and Abraham O. Fapojuwo Dept. of Electrical and Computer Engineering The University of Calgary, Calgary, AB, Canada WCNC 2008. Outline. Introduction System model - PowerPoint PPT PresentationTRANSCRIPT
A novel radio resource management approach for QoS Provisioning in multi-service
Multi-slot OFDMA Systems
Ahmed N. Zaki and Abraham O. Fapojuwo
Dept. of Electrical and Computer Engineering
The University of Calgary, Calgary, AB, Canada
WCNC 2008
Outline
• Introduction
• System model
• Optimal scheduling
• Suboptimal scheduling
• Simulation
• Conclusion
introduction
• In this paper, we consider the Radio Resource Management (RRM) in the downlink on OFDMA system
• RRM is the Problem of distributing– different resources
• Multi-user
introduction
• The general approach taken by all the past papers – Formulate the RRM problem– It can be optimally solved from the mathematic
al programming theory
• In the rest of thist paper will propose a suboptimal algorithm
introduction
• Assumptions– To allocate enough resource to each user– Each user will be satisfy a constant data rate– RT services are allocated a constant number of
bits every frame– Thus, each NRT services will depend on many
parameters
introduction
• Assumptions– Due to frequency selective fading, each user
may have a different SNR for the different subcarriers
– BS invokes the scheduling once during each frame
System model
• The total available bandwidth divided into K subchannels
• A frame length of W seconds• there are T available time slots per subchan
nel in the current frame• There are M different modulation/conding• There are N users that will be allocate resou
rce
System model
• let β denote the number of bits that can be transmitted in one time slot on any subchannel
• A logical subchannel is a physical subchannel that can only be used with one modulation/coding combination– Hence, the total number of logical subchannels G = K M.
– The number of data units transmitted on a logical subchannel ( Sg )
System model
• Xg,n equals the number of time slots allocated to the nth user on the gth logical subchannel
Optimal scheduling
Suboptimal scheduling_baseidea
• Network flow
SD1
a
b
cD2
82
3
4
5
8
67
Suboptimal scheduling_baseidea
• Network flow
SD1
a
b
cD2
82
3
4
5
8
67
Suboptimal scheduling_baseidea
• Network flow
SD1
a
b
cD2
82
3
4
5
8
67
2
3
33
2
30
5
3
Suboptimal scheduling_example
1
2
3
16
64
16
64
16
64
a
b
c
Subchannel usermodulation
10 slot
10 slot
10 slot
80 byte
120 byte
-5
-10
-5
-10
-10
-5-5
-530 byte
8 slot
12 slot
3 slot
2 slot
7 slot
0 slot
0 slot
Simulation
• The simulated system consists of a single cell
• The channel consists of 4 subchannels
• The available modulation schemes are QPSK, 16-QAM and 64-QAM
• The frame length is 10 msec
• Each subchannel has 7 time slots
Simulation
Simulation
Conclusion
• This paper proposed a novel approach for OFDMA radio resource management
• Simulations show that the proposed approach enhances the system performance