femtocell 1
Post on 07-Apr-2018
231 Views
Preview:
TRANSCRIPT
-
8/6/2019 Femtocell 1
1/30
Femtocells: Introduction
and Research Issues
By
Dharma P. Agrawal
Ohio Board of Regents Distinguished Professor of Computer ScienceOhio Board of Regents Distinguished Professor of Computer Science
Director, Center for Distributed and Mobile ComputingDirector, Center for Distributed and Mobile Computing
Computer Science DepartmentComputer Science Department
University of Cincinnati, Cincinnati, OH, 45221University of Cincinnati, Cincinnati, OH, 45221--00300030
Tel: 513Tel: 513--556556--47564756
EE--mail:mail: dpa@cs.uc.edu
dpa@cs.uc.edu,, www.cs.uc.edu/www
.cs.uc.edu/~dpa
mailto:dpa@cs.uc.edumailto:dpa@cs.uc.eduhttp://www.cs.uc.edu/~dpahttp://www.cs.uc.edu/~dpahttp://www.cs.uc.edu/~dpahttp://www.cs.uc.edu/~dpahttp://www.cs.uc.edu/mailto:dpa@cs.uc.edumailto:dpa@cs.uc.edu -
8/6/2019 Femtocell 1
2/30
Outline
n PART I: Introduction to Femtocells
n PART II: Research Topics
n PART III: Conclusions
2
-
8/6/2019 Femtocell 1
3/30
Background
n More people choose mobile handset for all voicecommunication
n More than 50% of voice call and
More than 70% of data traffic
from indoor environment
n Poor voice quality and slow data rates, even withoutany signal inside buildings because of high frequencyradio signals penetrating problem
All traffic Distribution
3
-
8/6/2019 Femtocell 1
4/30
What are Femtocells?
n Femtocells, short for femtocell base stations, are
low-power, short-range, low-cost indoor cellular basestation for better coverage and capacity
It is different than Access Point
4
-
8/6/2019 Femtocell 1
5/30
What are Femtocells
n The femto in femtocell means 10-15 . Femtocellsacquired the name because they are much smallerthan the standard Macrocell cellular towers
n Each of Femtocells works with the major wirelesstelecommunications standard and connects users
with cellular provider via broadband Internet links
5
-
8/6/2019 Femtocell 1
6/30
6
Telephone Core Network
difference
-
8/6/2019 Femtocell 1
7/30
Femtocell Interfaces
n Air In terface
UMTS
CDMA2000WiMax
LTE (Long Term Evolution basedon 3GPP) ("Home eNode B")
n Internet InterfaceDSL
Cable
Vodafone Gateway
7
-
8/6/2019 Femtocell 1
8/30
Femtocells Architecture
Another alternative architecture8One alternative architecture
-
8/6/2019 Femtocell 1
9/30
Why Femtocells?
Benefits For Cellular Users
n Better coverage
n Higher capacity
n Lower transmit power
n Prolong handset battery life
n Higher signal-to-interference-plus-noise ratio (SINR)
9
-
8/6/2019 Femtocell 1
10/30
Why Femtocells?
Benefits for Cellular Providers
n Improved Macrocell BSs reliability
n Offload data traffic from the Macrocell BSs
n Increasing the area spectral efficiency
(total number of active users per Hertz per unit area)n Operating Cost benefits
n But, no additional revenue
10
-
8/6/2019 Femtocell 1
11/30
Femtocell Development
n In 2002, a group of Motorola engineers introduced aHome Base Station technology
n In 2007, vendors formed the Femto Forum topromote femtocell use
n In 2008, Sprint Nextel released home-based 2Gfemtocell built by Samsung Electronics that workswith any Sprint handset
n In 2009, Verizon and Vodafone rolled out theirfemtocell network service with 3G standard
11
-
8/6/2019 Femtocell 1
12/30
Technology Comparisons
n
Femtocell VS Macrocell
n Femtocell VS WLAN
n Femtocell VS UMA(Unlicensed Mobile Access)
12
-
8/6/2019 Femtocell 1
13/30
Femtocell VS Macrocell
Femtocell Macrocell
Air interface Telecommunicationstandard
Telecommunicationstandard
Backhaul Broadband Internet Telephony network
Cost* $200/year $60,000/year
Cell phone
Power consumption
low high
Radio Range 10-50 meters 300-2000 meters
*Analysis, Http://research.analysis.com 13
http://research.analysis.com/http://research.analysis.com/ -
8/6/2019 Femtocell 1
14/30
Femtocell VS WLAN
Femtocell WLAN (AP)
Spectrum Licensed Unlicensed
MAC layer Conflict-free Contention-based
Backhaul Cable/DSL Cable/DSL
Air interface Cellular standard 802.11a/b/g/n
Range 10-50m 35-70m
Service Primarily voice Primarily data
Current Cost $200-$250 $50-$100
14
-
8/6/2019 Femtocell 1
15/30
Femtocell V/S UMA
n Unlicensed Mobile Access(UMA), an IP-based 3GPPstandard for connecting to
mobile networks viabroadband IP networks
n UMA provides access tomobile voice and dataservices over unlicensed-spectrum technologiessuch as WLAN
Femtocell UMA
Spectrum licensed unlicensed
Phone Mode Single mode Dual mode
Air interface Cellulartechnology
WLAN
technology
Backhaul Broadband
Internet
Broadband
Internet
15
-
8/6/2019 Femtocell 1
16/30
Outline
n PART I: Introduction to Femtocells
n PART II: Research Topics
n PART III: Conclusions
16
-
8/6/2019 Femtocell 1
17/30
Interference Between?
n Femtocell Macrocell (cross-tier)
n Femtocell - Femtocell
17
-
8/6/2019 Femtocell 1
18/30
Interference
n In CDMA systemInterference avoidance through time hopping and directional
antennas*
n In the LTE (Long Term Evolut ion based on3GPP) and Mobile W iMax system
Pow er control
Frequency assignment
*Vikram C. and Jeffrey G. A., Uplink capacity and interference avoidance for two-tier Femtocell networks
18
-
8/6/2019 Femtocell 1
19/30
Quality of service (VoIP)
n Existing Macrocell networks provide latencyguarantees
n Femtocell backhaul needs QoS for delay-sensitivetraffic and provides enough capacity
n Cellular provider can not control voice data priorityunless internet backhaul belongs to the same
company
n Dont forget! Originally, broadband internet is forWLAN traffic
19
-
8/6/2019 Femtocell 1
20/30
Handover???
n Femtocell to Macrocell
n Macrocell to Femtocell
n Femtocell to Femtocell
20
-
8/6/2019 Femtocell 1
21/30
Handover
n Frequent and unnecessary Handover
21
-
8/6/2019 Femtocell 1
22/30
Synchronization
n Synchronization is for:- Handover- Minimizing multi-access interference- Ensuring a tolerable carrier offset
n Proposed Solution:- Precision timing protocol over IP
- GPS- High-precision crystal oscillators
22
-
8/6/2019 Femtocell 1
23/30
Access control
n Open access
Provide service to anyone who pass nearbyn Closed access
A fixed set of home users are licensed to use femto
n Hybrid access
resources are reserved for registered family usersand others are open for roamers
23
-
8/6/2019 Femtocell 1
24/30
Self-Configuration & Self-operation
n Femtocell should be a plug-and-play device that canintegrate itself into mobile network
n A configuration function should be capable ofadjusting parameters under various environments
n Self-operation is needed in WiMax network. Forexample, Handover and radio resource management(RRM) are directly controlled by Macrocell BS andFemtocell BS
24
-
8/6/2019 Femtocell 1
25/30
Current Deployments
n Sprint started in 3Q/2007 as a limited rollout(Denver and Indianapolis)
n Starhub put in November 2008
n Verizon did in January of 2009
n Vodafone released in July of 2009
n
More operators in 2008: O2, Softbank,TeliaSonera, and Vodafone
n AT&T announced testing in Raleigh andCharlotte as of 28 October 2009
25
-
8/6/2019 Femtocell 1
26/30
Limitations
n Currently MIMO Femtocells
MIMO Femtocells can switch between providing
high data rates and robust transmission
n Security problem
Femtocells backhaul are local ISP networks, whichare different from cellular network and can be
accessed by anyone, including hackers
26
-
8/6/2019 Femtocell 1
27/30
Other Issues
n Adaptive power control
Sprints AIRAVE femtocell uses adaptive power
control for cross-tier interference
n Emergency Call & Location Tracking
Government required 911 call service with location
informationn GPS inside femtocells
n Location information over backhaul
n Pay for Femtocell provider as well asInternet service provider
27
-
8/6/2019 Femtocell 1
28/30
References
n Journal and Conference Papers
n
http://www.femtoforum.orgn http://www.airwalkcom.com/
nVodafone Homepage
n Sprint Homepage
28
http://www.femtoforum.org/http://www.airwalkcom.com/http://www.airwalkcom.com/http://www.femtoforum.org/ -
8/6/2019 Femtocell 1
29/30
Conclusions
n Observation: Femtocell provides goodindoor access and fills the voids, but no
additional revenue to service providern How to minimize interference?
n How to control the access?
n How to provide effective Handover?n How do you ensure security?
n How to charge more money to
customers??29
-
8/6/2019 Femtocell 1
30/30
30
Any Questions??dpa@cs.uc.edu
Future of 4-G???
mailto:dpa@cs.uc.edumailto:dpa@cs.uc.edu
top related