Cross-Layer Design in Cognitive Radio Networksstanzil/presentation.pdf · 2016-08-17 · Some...

33
Some Cross-Layer Design and Performance Issues in Cognitive Radio Networks S.M. Shahrear Tanzil M.A.Sc. Student School of Engineering The University of British Columbia Okanagan Supervisor: Dr. Md. Jahangir Hossain September 5, 2013 S.M. Shahrear Tanzil (UBC) 1 / 33 September 5, 2013 1 / 33

Transcript of Cross-Layer Design in Cognitive Radio Networksstanzil/presentation.pdf · 2016-08-17 · Some...

Page 1: Cross-Layer Design in Cognitive Radio Networksstanzil/presentation.pdf · 2016-08-17 · Some Cross-Layer Design and Performance Issues in Cognitive Radio Networks S.M. Shahrear Tanzil

Some Cross-Layer Design and Performance Issues inCognitive Radio Networks

S.M. Shahrear Tanzil

M.A.Sc. Student

School of Engineering

The University of British Columbia Okanagan

Supervisor: Dr. Md. Jahangir Hossain

September 5, 2013

S.M. Shahrear Tanzil (UBC) 1 / 33 September 5, 2013 1 / 33

Page 2: Cross-Layer Design in Cognitive Radio Networksstanzil/presentation.pdf · 2016-08-17 · Some Cross-Layer Design and Performance Issues in Cognitive Radio Networks S.M. Shahrear Tanzil

Outline

1 Introduction

2 Multi-Class Service Transmission over Cognitive Radio Network

3 Cross-Layer Performance in Presence of Sensing Errors

S.M. Shahrear Tanzil (UBC) 2 / 33 September 5, 2013 2 / 33

Page 3: Cross-Layer Design in Cognitive Radio Networksstanzil/presentation.pdf · 2016-08-17 · Some Cross-Layer Design and Performance Issues in Cognitive Radio Networks S.M. Shahrear Tanzil

Introduction

Introduction

Figure 1: Fixed spectrum access policy

S.M. Shahrear Tanzil (UBC) 3 / 33 September 5, 2013 3 / 33

Page 4: Cross-Layer Design in Cognitive Radio Networksstanzil/presentation.pdf · 2016-08-17 · Some Cross-Layer Design and Performance Issues in Cognitive Radio Networks S.M. Shahrear Tanzil

Introduction

Fixed Spectrum Access

A certain portion of radio spectrum is allocated/reserved for a certaingroup of users usually referred to as primary users (PUs)

Other group of potential users, usually referred to as secondary users(SUs) are not allowed to access the spectrum, even if a particularportion of the spectrum is currently not being used by the PUs

Recent studies on spectrum measurements have revealed that a largeportion of the assigned spectrum is used sporadically by the PUs

S.M. Shahrear Tanzil (UBC) 4 / 33 September 5, 2013 4 / 33

Page 5: Cross-Layer Design in Cognitive Radio Networksstanzil/presentation.pdf · 2016-08-17 · Some Cross-Layer Design and Performance Issues in Cognitive Radio Networks S.M. Shahrear Tanzil

Introduction

Dynamic Spectrum Access

SUs can share the assigned spectrum with the PUs opportunistically

Underlay methodOverlay method

Spectrum hole Spectrum hole

Spectrum hole Spectrum hole

Spectrum hole

Fre

qu

en

cy

Time

Figure 2: An example of overlay spectrum access with spectrum holes

S.M. Shahrear Tanzil (UBC) 5 / 33 September 5, 2013 5 / 33

Page 6: Cross-Layer Design in Cognitive Radio Networksstanzil/presentation.pdf · 2016-08-17 · Some Cross-Layer Design and Performance Issues in Cognitive Radio Networks S.M. Shahrear Tanzil

Introduction

Cognitive Radio

Facilitate dynamic spectrum access

Joseph Mitola proposed the concept of cognitive radio (CR)technology in 1998

Senses the spectrum of the PUs

Adapts various transmission and operating parameters including thefrequency range, modulation type, and power according to thewireless environment

S.M. Shahrear Tanzil (UBC) 6 / 33 September 5, 2013 6 / 33

Page 7: Cross-Layer Design in Cognitive Radio Networksstanzil/presentation.pdf · 2016-08-17 · Some Cross-Layer Design and Performance Issues in Cognitive Radio Networks S.M. Shahrear Tanzil

Introduction

Motivations

Wireless channel quality not only varies with time but also theavailability of radio spectrum depends on PUs’ activity

Multi-class services e.g., video conferencing, email transfer and webbrowsing have diverse quality of service (QoS) requirements in termsof delay and packet loss probability

One design challenge: How to develop innovative resource allocationmechanisms that can meet diverse QoS requirements of differentclasses of services transmitted over the cognitive radio network (CRN)

Another design challenge: Channel sensing errors

S.M. Shahrear Tanzil (UBC) 7 / 33 September 5, 2013 7 / 33

Page 8: Cross-Layer Design in Cognitive Radio Networksstanzil/presentation.pdf · 2016-08-17 · Some Cross-Layer Design and Performance Issues in Cognitive Radio Networks S.M. Shahrear Tanzil

Introduction

CRN Architecture: Infrastructure-Based

SU-1

CR BSPU BS

PU BS

SU-2

SU-K

Figure 3: Infrastructure-based CRN, CR=cognitive radio, BS=base station,PU=primary user, SU=secondary user.

S.M. Shahrear Tanzil (UBC) 8 / 33 September 5, 2013 8 / 33

Page 9: Cross-Layer Design in Cognitive Radio Networksstanzil/presentation.pdf · 2016-08-17 · Some Cross-Layer Design and Performance Issues in Cognitive Radio Networks S.M. Shahrear Tanzil

Introduction

Operating Assumptions

PUs’ activity: ON/OFF

Channel: Slowly time varying, Nakagami-m, finite state Markovchannel

Channel scheduling: Max rate

S.M. Shahrear Tanzil (UBC) 9 / 33 September 5, 2013 9 / 33

Page 10: Cross-Layer Design in Cognitive Radio Networksstanzil/presentation.pdf · 2016-08-17 · Some Cross-Layer Design and Performance Issues in Cognitive Radio Networks S.M. Shahrear Tanzil

Introduction

Cross-Layer Design

Physical layer

Data link layer

Pa

cke

ts fro

m h

igh

er

laye

r

Queue

Packet are transmitted

through the physical layer

Figure 4: Cross-layer design

Packet arrival follows batch Bernoulli random process

Packets are stored in the data link layer’s buffer/queue

Adaptive modulation and coding is employed

S.M. Shahrear Tanzil (UBC) 10 / 33 September 5, 2013 10 / 33

Page 11: Cross-Layer Design in Cognitive Radio Networksstanzil/presentation.pdf · 2016-08-17 · Some Cross-Layer Design and Performance Issues in Cognitive Radio Networks S.M. Shahrear Tanzil

Multi-Class Service Transmission over Cognitive Radio Network

Multi-Class Service

Voice, video streaming and web browsing have stringent delayconstraints i.e., delay sensitive (DS) service

Email has no stringent delay constraint i.e., delaynon-sensitive/best-effort (BE) service

S.M. Shahrear Tanzil (UBC) 11 / 33 September 5, 2013 11 / 33

Page 12: Cross-Layer Design in Cognitive Radio Networksstanzil/presentation.pdf · 2016-08-17 · Some Cross-Layer Design and Performance Issues in Cognitive Radio Networks S.M. Shahrear Tanzil

Multi-Class Service Transmission over Cognitive Radio Network

Rate Allocation Mechanism for a Particular SU

Buffer of delay sensitive service, Q(d)

Buffer of best effort service, Q(b)

Delay sensitive

packet arrival from

upper layer, β

Best effort

packet arrival

from upper

layer, α

kth user

rate

allocator

Allocated total transmission rate to user k

Rate of

delay

sensitive

service, R(d)

Rate of best

effort

service, R(b)

Figure 5: Rate allocation for multi-class service transmission for kth SU.

S.M. Shahrear Tanzil (UBC) 12 / 33 September 5, 2013 12 / 33

Page 13: Cross-Layer Design in Cognitive Radio Networksstanzil/presentation.pdf · 2016-08-17 · Some Cross-Layer Design and Performance Issues in Cognitive Radio Networks S.M. Shahrear Tanzil

Multi-Class Service Transmission over Cognitive Radio Network

Optimal Rate Allocation Mechanism

Formulated the problem as a constrained Markov decision process(MDP)

Objective

minimizex(S,A)

[d(d ,o)(S,A)]ᵀx(S,A) (1)

subject to:[p(b,o)loss (S,A)]ᵀx(S,A) ≤ p

(b)th (2)

[p(d ,o)loss (S,A)]ᵀx(S,A) ≤ p

(d)th (3)

p(b)th and p

(d)th are target packet loss probabilities of BE service and DS

service, respectively

S.M. Shahrear Tanzil (UBC) 13 / 33 September 5, 2013 13 / 33

Page 14: Cross-Layer Design in Cognitive Radio Networksstanzil/presentation.pdf · 2016-08-17 · Some Cross-Layer Design and Performance Issues in Cognitive Radio Networks S.M. Shahrear Tanzil

Multi-Class Service Transmission over Cognitive Radio Network

Optimal Rate Allocation Mechanism

x∗(S,A) denotes the probability of taking action A in state S thatminimizes the average queuing delay of DS packets while satisfiespacket loss probability constraints

From the optimal values, x∗(S,A) one can calculate QoS parameterse.g., packet loss probabilities and queuing delay

The optimal policies for constrained MDP are random

S.M. Shahrear Tanzil (UBC) 14 / 33 September 5, 2013 14 / 33

Page 15: Cross-Layer Design in Cognitive Radio Networksstanzil/presentation.pdf · 2016-08-17 · Some Cross-Layer Design and Performance Issues in Cognitive Radio Networks S.M. Shahrear Tanzil

Multi-Class Service Transmission over Cognitive Radio Network

Suboptimal Rate Allocation Mechanism

1: if Available transmission rate,R ≤ number of packets in the DS buffer then

2: R(d) ← R3: R(b) ← 04: else5: R(d) ← number of packets in the DS buffer6: R(b) ← R − R(d)

7: end if

S.M. Shahrear Tanzil (UBC) 15 / 33 September 5, 2013 15 / 33

Page 16: Cross-Layer Design in Cognitive Radio Networksstanzil/presentation.pdf · 2016-08-17 · Some Cross-Layer Design and Performance Issues in Cognitive Radio Networks S.M. Shahrear Tanzil

Multi-Class Service Transmission over Cognitive Radio Network

Suboptimal Rate Allocation Mechanism

Developed a queuing analytic model with the suboptimal rateallocation mechanism

Analyzed queuing analytic model as a quasi-birth-death (QBD)process

Calculated packet loss probabilities and queuing delay i.e., delaydistribution from the steady state probabilities of the QBD

S.M. Shahrear Tanzil (UBC) 16 / 33 September 5, 2013 16 / 33

Page 17: Cross-Layer Design in Cognitive Radio Networksstanzil/presentation.pdf · 2016-08-17 · Some Cross-Layer Design and Performance Issues in Cognitive Radio Networks S.M. Shahrear Tanzil

Multi-Class Service Transmission over Cognitive Radio Network

Numerical Results: Cumulative Distribution ofDelay of DS Packets

0 10 20 30 40 500

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

X: 10Y: 0.7156

time slots (X)

Pro

b.(d

elay

≤ X

) of

DS

pac

kets

X: 10Y: 0.8304

Suboptimal,K=2(ana)Optimal,K=2(sim)Suboptimal,K=3(ana)Optimal,K=3(sim)Suboptimal,K=4(ana)Optimal,K=4(sim)

Figure 6: Effect of number of SUs (K ) on the delay distribution of DS packets(ana=analysis, sim=simulation)

S.M. Shahrear Tanzil (UBC) 17 / 33 September 5, 2013 17 / 33

Page 18: Cross-Layer Design in Cognitive Radio Networksstanzil/presentation.pdf · 2016-08-17 · Some Cross-Layer Design and Performance Issues in Cognitive Radio Networks S.M. Shahrear Tanzil

Multi-Class Service Transmission over Cognitive Radio Network

Numerical Results: Packet Loss Probability of DSservice

1 2 3 4 50

0.01

0.02

0.03

0.04

0.05

0.06

X: 5Y: 0.05227

Number of secondary users

Pac

ket l

oss

prob

abili

ty o

f DS

ser

vice

X: 4Y: 0.03542

Suboptimal,(ana)

Optimal,(ana)

Figure 7: Effect of number of SUs (K ) on the packet loss probability of DSservice (ana=analysis, sim=simulation)

S.M. Shahrear Tanzil (UBC) 18 / 33 September 5, 2013 18 / 33

Page 19: Cross-Layer Design in Cognitive Radio Networksstanzil/presentation.pdf · 2016-08-17 · Some Cross-Layer Design and Performance Issues in Cognitive Radio Networks S.M. Shahrear Tanzil

Multi-Class Service Transmission over Cognitive Radio Network

Numerical Results: Packet Loss Probability of BEservice

1 2 3 4 50

0.02

0.04

0.06

0.08

0.1

0.12

0.14

0.16

0.18

0.2

X: 3Y: 0.06752

Number of secondary users

Pac

ket l

oss

prob

abili

ty o

f BE

ser

vice

X: 2Y: 0.008732 Suboptimal,(ana)

Optimal(ana)

Figure 8: Effect of number of SUs (K ) on the packet loss probability of BEservice (ana=analysis, sim=simulation)

S.M. Shahrear Tanzil (UBC) 19 / 33 September 5, 2013 19 / 33

Page 20: Cross-Layer Design in Cognitive Radio Networksstanzil/presentation.pdf · 2016-08-17 · Some Cross-Layer Design and Performance Issues in Cognitive Radio Networks S.M. Shahrear Tanzil

Multi-Class Service Transmission over Cognitive Radio Network

Application of the Developed Queuing Model with theSuboptimal Mechanism: Example

Table 1: Number of SUs for given QoS requirements (D(d,s)t,max = 10 (time slots)

with probability=0.8,P(d,s)t,loss ≤ 0.05 and P

(b,s)t,loss ≤ 0.05)

KD

(d,s)t,max

KP

(d,s)t,loss

KP

(b,s)t,loss

Ks

3 4 2 2

S.M. Shahrear Tanzil (UBC) 20 / 33 September 5, 2013 20 / 33

Page 21: Cross-Layer Design in Cognitive Radio Networksstanzil/presentation.pdf · 2016-08-17 · Some Cross-Layer Design and Performance Issues in Cognitive Radio Networks S.M. Shahrear Tanzil

Multi-Class Service Transmission over Cognitive Radio Network

Summary: Part I

Studied rate allocation mechanisms that allocate rate between twodifferent classes of services of a particular SU

Formulated the optimal rate allocation mechanism as a MDP

Also proposed a low-complexity suboptimal rate allocation mechanism

The performance of the suboptimal rate mechanism is quite similar tothe optimal rate allocation mechanism

Developed queuing analytic model with the suboptimal mechanism isuseful not only for calculating QoS parameters but also in making acall admission control decision

S.M. Shahrear Tanzil (UBC) 21 / 33 September 5, 2013 21 / 33

Page 22: Cross-Layer Design in Cognitive Radio Networksstanzil/presentation.pdf · 2016-08-17 · Some Cross-Layer Design and Performance Issues in Cognitive Radio Networks S.M. Shahrear Tanzil

Multi-Class Service Transmission over Cognitive Radio Network

Publication

S M Shahrear Tanzil, Md. Jahangir Hossain, and Mohammad MRashid ,“Rate allocation mechanisms for multi-class service transmission overcognitive radio networks”, accepted inIEEE Global Commun. Conf. (Globecom’13), Atlanta, USA, Dec.2013.

S.M. Shahrear Tanzil (UBC) 22 / 33 September 5, 2013 22 / 33

Page 23: Cross-Layer Design in Cognitive Radio Networksstanzil/presentation.pdf · 2016-08-17 · Some Cross-Layer Design and Performance Issues in Cognitive Radio Networks S.M. Shahrear Tanzil

Cross-Layer Performance in Presence of Sensing Errors

Sensing Errors in Cognitive Radio Systems

Two types of sensing errors i.e., false alarm and miss-detection

False alarm: CRN may detect a channel being used by PUs where inreality the channel is idle/PUs are not using the channel

Miss-detection: CRN may not be able to detect an active PU

S.M. Shahrear Tanzil (UBC) 23 / 33 September 5, 2013 23 / 33

Page 24: Cross-Layer Design in Cognitive Radio Networksstanzil/presentation.pdf · 2016-08-17 · Some Cross-Layer Design and Performance Issues in Cognitive Radio Networks S.M. Shahrear Tanzil

Cross-Layer Performance in Presence of Sensing Errors

Random Transmission Protocol

Traditional deterministic protocol: If the channel is sensed as busy,CR base station (BS) decides to transmit with probability, 0

False alarm: Sensed as busy but in reality idle

Random transmission protocol: If the channel is sensed as busy, CRBS decides to transmit with probability, P1

S.M. Shahrear Tanzil (UBC) 24 / 33 September 5, 2013 24 / 33

Page 25: Cross-Layer Design in Cognitive Radio Networksstanzil/presentation.pdf · 2016-08-17 · Some Cross-Layer Design and Performance Issues in Cognitive Radio Networks S.M. Shahrear Tanzil

Cross-Layer Performance in Presence of Sensing Errors

Random Transmission Protocol

Traditional deterministic protocol: If the channel is sensed as idle, CRBS decides to transmit with probability, 1

Miss-detection: Sensed as idle but in reality busy

Random transmission protocol: If the channel is sensed as idle, CRBS decides to transmit with probability, P2

S.M. Shahrear Tanzil (UBC) 25 / 33 September 5, 2013 25 / 33

Page 26: Cross-Layer Design in Cognitive Radio Networksstanzil/presentation.pdf · 2016-08-17 · Some Cross-Layer Design and Performance Issues in Cognitive Radio Networks S.M. Shahrear Tanzil

Cross-Layer Performance in Presence of Sensing Errors

Queuing Analytic Model

Developed a queuing analytic model

Analyzed the queuing analytic model as a QBD process

Calculated QoS parameters of SUs e.g., packet loss probability andqueuing delay as well as QoS parameters of PUs e.g., collisionprobability from the steady state probabilities of the QBD

S.M. Shahrear Tanzil (UBC) 26 / 33 September 5, 2013 26 / 33

Page 27: Cross-Layer Design in Cognitive Radio Networksstanzil/presentation.pdf · 2016-08-17 · Some Cross-Layer Design and Performance Issues in Cognitive Radio Networks S.M. Shahrear Tanzil

Cross-Layer Performance in Presence of Sensing Errors

Numerical Results: Packet Loss Probability

1 2 3 4 5 6 7 8 9 100.13

0.135

0.14

0.145

X: 8Y: 0.1401

Number of secondary users (K)

Pac

ket l

oss

prob

abili

ty

P1=0,P2=1(ana)P1=0.1,P2=1(ana)P1=0,P2=0.9(ana)

Figure 9: Effect of the values of P1, P2 and SUs (K ) on the packet lossprobability (ana=analysis).

S.M. Shahrear Tanzil (UBC) 27 / 33 September 5, 2013 27 / 33

Page 28: Cross-Layer Design in Cognitive Radio Networksstanzil/presentation.pdf · 2016-08-17 · Some Cross-Layer Design and Performance Issues in Cognitive Radio Networks S.M. Shahrear Tanzil

Cross-Layer Performance in Presence of Sensing Errors

Numerical Results: Average Queuing Delay

1 2 3 4 5 6 7 8 9 1074.5

75

75.5

76

76.5

77

77.5

Number of secondary users (K)

Ave

rage

que

uein

g de

lay

(tim

e sl

ots)

P1=0,P2=1(ana)P1=0.1,P2=1(ana)P1=0,P2=0.9(ana)

Figure 10: Effect of the values of P1,P2 and SUs (K ) on average queuing delay(ana=analysis).

S.M. Shahrear Tanzil (UBC) 28 / 33 September 5, 2013 28 / 33

Page 29: Cross-Layer Design in Cognitive Radio Networksstanzil/presentation.pdf · 2016-08-17 · Some Cross-Layer Design and Performance Issues in Cognitive Radio Networks S.M. Shahrear Tanzil

Cross-Layer Performance in Presence of Sensing Errors

Numerical Results: Collision Probability

1 2 3 4 5 6 7 8 9 100.01

0.02

0.03

0.04

0.05

0.06

0.07

0.08

X: 8Y: 0.07117

Number of secondary users (K)

Ove

rall

colli

sion

pro

babi

lity

X: 7Y: 0.06684

P1=0.1,P2=1(ana)P1=0,P2=0.9(ana)P1=0,P2=1(ana)

Figure 11: Effect of the values of P1, P2 and SUs (K ) on the collision probability(ana=analysis).

S.M. Shahrear Tanzil (UBC) 29 / 33 September 5, 2013 29 / 33

Page 30: Cross-Layer Design in Cognitive Radio Networksstanzil/presentation.pdf · 2016-08-17 · Some Cross-Layer Design and Performance Issues in Cognitive Radio Networks S.M. Shahrear Tanzil

Cross-Layer Performance in Presence of Sensing Errors

Application of the Developed Model: Example

Table 2: Transmission Probabilities (P1,P2) vs. number of SUs for given QoSrequirements (pt,ploss = 0.14, Dt,avg = 77 (time slots) and pt,col = 0.07 )

(P1,P2) Kpt,ploss KDt,avg Kpt,col Ks

(0,0.9) 6 9 15 6(0,1) 7 11 13 7

(0.1,1) 8 12 8 8

S.M. Shahrear Tanzil (UBC) 30 / 33 September 5, 2013 30 / 33

Page 31: Cross-Layer Design in Cognitive Radio Networksstanzil/presentation.pdf · 2016-08-17 · Some Cross-Layer Design and Performance Issues in Cognitive Radio Networks S.M. Shahrear Tanzil

Cross-Layer Performance in Presence of Sensing Errors

Summary: Part II

Investigated the performance of a random transmission protocol

Developed a queuing analytic model in presence of sensing errors

Calculated different QoS parameters using the developed queuingmodel

The queuing analytic model is also useful for admission control

Selected numerical results have shown that random transmissionprotocol can support more SUs than the classical deterministictransmission protocol

S.M. Shahrear Tanzil (UBC) 31 / 33 September 5, 2013 31 / 33

Page 32: Cross-Layer Design in Cognitive Radio Networksstanzil/presentation.pdf · 2016-08-17 · Some Cross-Layer Design and Performance Issues in Cognitive Radio Networks S.M. Shahrear Tanzil

Cross-Layer Performance in Presence of Sensing Errors

Publication

S M Shahrear Tanzil and Md. Jahangir Hossain,“Cross-layer performance analysis for cognitive radio network with arandom transmission protocol in presence of sensing errors”,in Proc. of Int. Conf. on Cognitive Radio Oriented Wireless Networks(CROWNCOM’13), Washington DC, USA, Jul. 2013.

S.M. Shahrear Tanzil (UBC) 32 / 33 September 5, 2013 32 / 33

Page 33: Cross-Layer Design in Cognitive Radio Networksstanzil/presentation.pdf · 2016-08-17 · Some Cross-Layer Design and Performance Issues in Cognitive Radio Networks S.M. Shahrear Tanzil

Cross-Layer Performance in Presence of Sensing Errors

Thank you!

S.M. Shahrear Tanzil (UBC) 33 / 33 September 5, 2013 33 / 33