EL9383: Special Topics in Wireless Networking

anisesecretaryMobile - Wireless

Dec 12, 2013 (3 years and 8 months ago)

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EL9383: Special Topics in

Wireless Networking


Professor: Sundeep Rangan


Spring semester 2012.

Wednesdays
,

6 to 8:30pm (classroom TBD)

Overview
:

An introduction to wireless communications with a focus on the MAC, networking and
application layers. Topics
include

channel and rate modeling, interference and spatial reuse, ARQ,
buffer management, QoS, random access, scheduling, mobility, intermittent

communication and
wireless security.


O
verviews and examples from state
-
of
-
the
-
art cellular and wireless LAN systems

will
be provided
. The course is designed for students both intending to specialize in wireless
communications as well as students who
are interested in the consequences of wireless
communication
s

in other areas including multimedia delivery, networking or mobile applications.

Prerequesites: Unde
rgrad probability and
EL5363 (Principles of Communication Networks)

or
e
quivalen
t
. No wirele
ss or digital communications classes are required.

Text: None. References in papers will be provided with each lecture.

Grading: 4 homeworks, midterm and final.

Tentative s
yllabus:

13 lectures of 2.5

hours each.

0.

Overview

(presented with Lecture 1)

o

The

wireless revolution

o

History

o

Challenges for wireless communications

o

Course admin details

1.

Basics of w
ireless
channels and communication

o

Components of a wireless transmitter and receiver

o

Bandwidth, duplexing, licenced and unlicensed bands

o

Power, rate and SN
R

o

Shannon’s capacity
, bandwidth and power
-
limited regimes
, modeling of practical receivers

o

D
istance
-
based path loss and

shadowing

o

Fading: Qualitative overview, coherence time and bandwidth

2.

Rate variability at the link layer

o

Challenges for reliable
transmission with rate variability

o

Open loop

techniques:
Outage probability, f
ade margin

o

Problems with fade margin compensation

o

Basic ARQ mechanisms
: stop
-
and
-
wait, go back N, selective ACK

o

Rate selection with ARQ

o

Channel quality feedback

o

Adaptive rate

selection

o

Example 1: 802.11 rate selection (trial & error system for low mobility)

o

Example 2: HSDPA rate selection (CQI based with high mobility)

3.

End
-
to
-
end e
ffects o
f rate v
ariability

o

B
asics of buffering

o

Buffer size
, delay

and fading duration


o

Basics o
f flow control

o

TCP flow control

o

Review of TCP congestion control mechanism

o

TCP over wireless

4.

Random access systems

o

Basic principles and types of multiplexing

o

Fixed assignment vs. statistical multiplexing

o

Aloha, slotted Aloha

o

Review of Poisson process

o

Analy
sis of Aloha

o

CSMA

with collision avoidance and collision detection

o

Analysis of CSMA

5.

802.11 WiFi

in depth

o

History and motivation

o

Architecture

o

DCF mode, RTS
-
CTS, hidden and exposed terminal problem

o

PCF mode

o

802.11n enhancements

6.

Segmentation and reassembly

o

Why fragment? MAC vs. IP
-
layer packet sizes

o

Example 1:
Fragmentation in 802.11



Basic fragmentation



Block transmissions in 802.11n

o

Example 2:
The radio link control (RLC) layer in 3GPP



Logical channels, MAC transport block
s



RLC layer with fixed MAC pack
et sizes



RLC layer with variable MAC packet size
s


o

A preview of mutliflow concepts

7.

Interference, spatial reuse and c
ellular
systems

o

What is interference? SINR calculations.

o

Cellular concept

and spatial reuse

o

Interference
-
limited and coverage
-
limited
systems

o

Frequency reuse

o

Cellular vs. WiFi. The exposed terminal problem revisited

o

Why does adding more WiFi access point not improve capacity?

8.

CDMA and UMTS

o

History and motivation of UMTS

o

CDMA basics: spreading, dispreading, SINR calculations

o

Spatial reu
se gains with CDMA

o

UMTS architecture and protocol stack

o

Release 99 circuit switched communication

o

Near
-
far effect and power control

o

HSDPA
(High Speed Dowlink Packet Access)

o

HSUPA
(High Speed Uplink Packet Access)

9.

OFDM and
LTE

o

History and motivation for
LTE

o

Network architecture and
protocol stack

o

Basics of OFDM

o

Downlink communication

o

Uplink communication

10.

Quality of service and scheduling

o

What is quality of service?

o

Requirements of typical applications.

o

T
raffic flow concept

o

Queues, head
-
of
-
line blocking
.

o

Multicommodity flows, packet drop mechanisms and fairness
.

o

Multi
-
user scheduling in HSDPA

o

Multi
-
user scheduling in LTE

o

QoS in 802.11e

11.

Mobility

o

Principles of handovers: switching conditions, hysteresis, detection.

o

Mobility at different layers.
Application vs. network
-
layer mobility.

o

Mobility in cellular systems



The gateway concept, measurement reports
, bearer management, mobility
procedures



Cellular backhaul technologies in use today.

o

Mobile IP



Basic components, tunneling



Route optimization



Enha
ncements for Mobile IPv6

o

Vertical handovers



Handovers in the EPC and PMIPv6

12.

Intermittent Communication and Power

Management

o

Power consumption on smartphones
.

o

The cost of

background communication.


o

Intermittent communication in cellular



Slotted paging, tr
acking areas, location updates



Idle mode handover

and cell selection

/ reselection



Discontinuous transmission and reception (DTX and DRX)

o

Wireless personal area networks (PANs)



Bluetooth 802.15.1



Zigbee 802.15.4

13.

Wireless s
ecurity

o

Components of security:
Encryption and integrity

o

Keys and ciphering

o

Authentication systems, EAP and AAA

o

Example 1: Security in WiFi: WEP, WPA and WPA2

o

Example 2: Security in cellular systems

o

Public key systems and Diffie
-
Hellman key exchange

o

IPSEC

o

Example 3: Secure access fro
m WiFi into cellular

o

Security procedures and handovers