Transcript Wireless Antenna Distribution and LTE HetNets Kenneth R. Baker, PhD University of Colorado at Boulder Interdisciplinary Telecommunications Program Presented at: Wireless @ Virginia Tech 2012 Symposium & Summer.

Wireless Antenna
Distribution and LTE
HetNets
Kenneth R. Baker, PhD
University of Colorado at Boulder
Interdisciplinary Telecommunications Program
Presented at:
Wireless @ Virginia Tech
2012 Symposium & Summer School on
Wireless Communications
May 31, 2012
CU-Boulder
Thesis
Indoor Distribution as path for LTE HetNets
• An introduction to Indoor and Outdoor
Distributed Antenna Systems.
•
State of the art today
• Describe how these systems form a
migration path to hierarchical cell
structures planned for 4G/LTE cellular
networks.
•
May 31, 2012
A review of LTE HCS related standards
Ken Baker (http://morse.colorado.edu/~kkbaker/)
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3
DAS Systems
A Distributed Antenna System (DAS) is a network of spatially separated antenna nodes
connected to a common source via a transport medium that provides wireless service
within a geographic area or structure (the DAS Forum)
Provide better coverage in environments like:
• Outdoor: Highways, Downtowns, Subways, Tunnels, University Campuses
• Indoor: Corporate Offices, Stadiums, Shopping Complexes, Airports, Convention
Centers, Hospitals, Hotels etc.
60% of voice traffic and 90% of data traffic from indoors.
(ABI Research)
DAS systems with overall market value of $5.5 billion comprises 96% of indoor
systems
(ABI Research)
DAS Concept was introduced by Saleh etal in 1987 as a solution for better indoor
coverage using leaky coax cable to simulcast the RF signal.
(A.A.M. Saleh, A.J. Rustako, and
R.S. Roman, “Distributed antennas for indoor radio communications,” IEEE Trans. Commn., vol. 35, pp. 1245–1251,
Dec. 1987)
May 31, 2012
Ken Baker (http://morse.colorado.edu/~kkbaker/)
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Why DAS is needed?
Indoor:
•
Poor coverage in basements, higher floors (above 25
floors), elevators, inner rooms (due to wall attenuations).
•
Large reflections from walls, roofs, tinted glass windows.
Outdoor:
•
Other buildings block the coverage in dense areas like
downtowns.
•
To provide coverage to long Highways/tunnels.
May 31, 2012
Ken Baker (http://morse.colorado.edu/~kkbaker/)
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DAS Components
5
Donor Unit
•
BSS, External Antennas
Interconnection Network
•
Active & Passive Head Ends
and Distribution Units
•
Coax/Fiber/Repeaters
•
Star or Cascade Connections
Remote Unit
•
RAUs & multi/wide band
antennas
May 31, 2012
Ken Baker (http://morse.colorado.edu/~kkbaker/)
Image source: http://www.accu-tech.com/das/
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Example Airport DAS
May 31, 2012
Ken Baker (http://morse.colorado.edu/~kkbaker/)
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Example: Outdoor DAS
Outdoor DAS serving a
University Campus
• Neutral Host System
• Two Cellular
Operators share the
transport
infrastructure
• They also share
antennas
May 31, 2012
Ken Baker (http://morse.colorado.edu/~kkbaker/)
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May 31, 2012
Ken Baker (http://morse.colorado.edu/~kkbaker/)
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Interconnection Media
Coax
• Cables: 50 ohm (RG174, RG58, LMR240, Standard Heliax etc)
• Connectors: SMA, BNC, TNC, N, 7/16 etc.
• Other Components: Couplers, Splitters, Bi-Directional Amplifiers
Optic Fiber
• Cables: Single Mode, Multimode, Step Index, Graded Index
• Connectors: FC,SC, ST, LC or MTRJ
• Other Components: Splicers, Splitters, Attenuators, WDM multiplexers, Laser Diodes
Over the Air (RF)
• Repeaters or Bi-Directional Amplifiers (BDA),
• Antennas: Isotropic, Dipole, Yagi, Panel, Leaky Coax
Hybrid Fiber Cable (HFC): CATV Networks
May 31, 2012
Ken Baker (http://morse.colorado.edu/~kkbaker/)
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Benefits of DAS (Chow, et al. 1994)
d
RADIO
RADIO
Single Antenna System
DAS
Consider single slope propagation model:
•
𝑃𝑎𝑡ℎ 𝐿𝑜𝑠𝑠 =
•
•
•
•
PT = Transmitted Power
PR = Received Power
C = Path loss at reference distance
γ = Path loss exponent
May 31, 2012
𝑃𝑇
𝐴
= 𝐶. 𝑑 𝛾 = 𝐶.
𝑃𝑅
𝜋
•
•
𝛾
2
d = radius of the macro-cell
A = area of the macro-cell = πd2
Ken Baker (http://morse.colorado.edu/~kkbaker/)
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Benefits of DAS (contd.)
Improvement in Coverage:
• Area of coverage of single antenna is given by:
𝑃𝑇
𝐴𝑠 = 𝜋
𝐶. 𝑃𝑅
2
𝛾
• Assuming transmitted power is equally divided between N
antennas of the DAS, area covered by each individual antenna is
given by:
𝐴1 = 𝐴2 = 𝐴3 = …. = 𝐴𝑁 = 𝜋
• Therefore, total area:
𝐴𝑡𝑜𝑡 =
𝑁
𝑖 𝐴𝑖
= 𝑁
1−
𝑃𝑇
𝑁
2
𝛾
𝐶.𝑃𝑅
2
𝛾
= 𝑁
2
−𝛾
𝐴𝑠
𝐴𝑠
• Thus, coverage is increased by a factor of:
2
1− 𝛾
𝑁
May 31, 2012
Ken Baker (http://morse.colorado.edu/~kkbaker/)
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Benefits of DAS (contd.)
Reduction in Transmit Power (Forward Link):
For single antenna system:
𝑃𝑇𝑠
𝑃𝑅
𝛾
= 𝐶. 𝑑 𝛾 = 𝐶.
𝐴 2
𝜋
Assuming transmitted power is equally divided between N
antennas of the DAS:
𝛾
𝑃𝑇𝑁
2
𝐴
𝑁 = 𝐶.
𝑁
𝑃𝑅
𝜋
• Therefore, total area: 𝑃𝑇𝑁 = 𝑁
𝛾
1− 2
𝑃𝑇𝑆
• Thus, transmitted power is reduced by a factor of:
𝑁
1−
𝛾
2
• On Reverse Link, assuming that path loss is reciprocal, mobiles
have to transmit only 1/N of the base station to communicate to a
𝛾
−2
single DAS antenna. Thus power is reduced by a factor of: 𝑁
May 31, 2012
Ken Baker (http://morse.colorado.edu/~kkbaker/)
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Q. What’s the vision? A. Small Cells
Heterogeneous Networks
•
•
a.k.a. Multi-Tier Networks
Better Coverage, More Capacity
Incorporated in 3GPP LTE Standards
•
•
Includes New Network Elements
Includes Interference and Mobility Management Techniques
May 31, 2012
Ken Baker (http://morse.colorado.edu/~kkbaker/)
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Indoor Distribution Today
•
•
•
•
Outdoor DAS
Indoor DAS
Neutral Host vs. Single Carrier
Passive vs. Active
The first steps to HetNets …
•
•
WIFI Off-load in Stadiums
Femtocells (Home Node-B’s)
May 31, 2012
Ken Baker (http://morse.colorado.edu/~kkbaker/)
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Indoor Distribution Today
•
•
•
•
Outdoor DAS
Indoor DAS
Neutral Host vs. Single Carrier
Passive vs. Active
The first steps to HetNets …
•
•
WIFI Off-load in Stadiums
Femtocells (Home Node-B’s)
May 31, 2012
Ken Baker (http://morse.colorado.edu/~kkbaker/)
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Sports Stadium as a Specific Example
May 31, 2012
Ken Baker (http://morse.colorado.edu/~kkbaker/)
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Traffic Statistics from a Sports Stadium
Example Traffic profiling look at data services usage during a game
Stadium Traffic Facts (with 60-90K Fans)
SMS: 200-600K
Data Calls: 300K-1M
Voice calls: 30-60K
Data Volume: 4-9 GB
Data services used during events
6%
2%
11%
42%
15%
Numbers are cumulative over the duration of a game
24%
 Data services on Smartphones are driving
the traffic today
 Background traffic from applications like
Twitter, Email, etc. is a significant contributor
May 31, 2012
Streaming
Web browsing
App Store Access
Smartphone Apps
Email
Other
Ken Baker (http://morse.colorado.edu/~kkbaker/)
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Stadium Traffic Will Continue to Increase
It is expected that mobile video will account for the majority of data growth
May 31, 2012
Ken Baker (http://morse.colorado.edu/~kkbaker/)
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Stadium Antennas
May 31, 2012
Ken Baker (http://morse.colorado.edu/~kkbaker/)
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Bowl Design and Some Statistics
Stadium
No. WiFi APs
No. Sectors
No. 1.25 MHz
Carriers (Voice/Data)
U. Michigan
~
15
5/7
Met Life
~
12
8/9
Lucas Field
1020
15
5/9
Mile High
500
12
6/8
May 31, 2012
Ken Baker (http://morse.colorado.edu/~kkbaker/)
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Super Bowl Data Usage
(One of three operators)
May 31, 2012
Ken Baker (http://morse.colorado.edu/~kkbaker/)
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Offload will get easier: “Hot Spot 2.0”
Three components:
1. IEEE 802.11u
•
•
Pre-association
published on February 25, 2011
2. Wi-Fi Protected Access 2 (WPA2)-Enterprise
3. Extensible Authentication Protocol (EAP)
•
•
EAP-SIM (GSM)
EAP-AKA (UMTS)
Mobility Services Advertisement Protocol (MSAP)
•
transported via IEEE 802.11u Generic Advertisement
Service (GAS)
See also: IEEE 802.21
•
enables seamless handover between networks
May 31, 2012
Ken Baker (http://morse.colorado.edu/~kkbaker/)
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Indoor Distribution Today
•
•
•
•
Outdoor DAS
Indoor DAS
Neutral Host vs. Single Carrier
Passive vs. Active
The first steps to HetNets …
•
•
WIFI Off-load in Stadiums
Femtocells (Home Node-B’s)
May 31, 2012
Ken Baker (http://morse.colorado.edu/~kkbaker/)
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Femtocell Overview
Femtocell
•
•
•
Ethernet Backhaul
In-home base station
Enterprise Base Station
3 Satellites
GPS
ISP
Femtocell
Core
Network
xDSL/Cable
Modem
Minimal Customer Requirements:
•
•
Any wireless handset or data device
A broadband connection and router
May 31, 2012
Ken Baker (http://morse.colorado.edu/~kkbaker/)
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Example: Dual-Mode EvDO product
Bottom Line: It’s a Plug and Play Cellular Base Station
May 31, 2012
Ken Baker (http://morse.colorado.edu/~kkbaker/)
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Femtocell Interference
Femtocells as two tier network
• Open: Any cell phone can attach
• Closed: Only specified cell phones can attach
BS of
Macro cell
Femto Cell
Femto Cell
Femto
BS
Femto
BS
Legend
Connection to BS
Interference from
Macro to Femto
and Femto to
Macro
User of
Femto cell
Interference form
Femto to Femto
User of
Macro cell
Femto
BS
Femto Cell
Femto
BS
Femto Cell
Downlink Femtocell Interference
May 31, 2012
Ken Baker (http://morse.colorado.edu/~kkbaker/)
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Femtocell Summary
3G Femtocells Today:
•
•
Can hand out to the macro layer
Cannot hand-in from the macro layer
4G (LTE) Femtocells:
•
Will enable both hand-in and hand-out between the
femto layer and the macro
• Femto to Femto handover should also be possible.
May 31, 2012
Ken Baker (http://morse.colorado.edu/~kkbaker/)
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Looking ahead to LTE
•
•
Carrier Aggregation
Higher Order Modulation
Fig. after Nokia Siemens
May 31, 2012
•
•
4G
MIMO
IEEE 802.16
Ken Baker (http://morse.colorado.edu/~kkbaker/)
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Why LTE?
May 31, 2012
Ken Baker (http://morse.colorado.edu/~kkbaker/)
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LTE, LTE-A, and 4G
May 31, 2012
Ken Baker (http://morse.colorado.edu/~kkbaker/)
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LTE Network
MME: Mobility Management Entity
•
Manages mobility, UE Identity and
Security Parameters
S-GW: Serving Gateway
•
Evolved Packet Core Interface to EUTRAN
P-GW: Packet Gateway
•
Evolved Packet Core Interface to
Packet Data Network
eNB: Evolved Node B
•
Performs all Radio Interface Related
Functions
Interfaces
•
•
X2: between eNBs
S1: between eNB and MME/S-GW
May 31, 2012
Ken Baker (http://morse.colorado.edu/~kkbaker/)
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Network Elements
Element
Backhaul
Coverage
Antennas
Macro-Cell
S1*
≥ 500m
At or above
rooftop level
Pico-Cell
S1*
≤ 500m,
Indoors
Rooftop or
below
Femtocell
IP
Indoors
Tabletop
Relay
LTE
≤ 500m,
Indoors
Below rooftop
*S1-C: Stream Control Transmission Protocol / IP (SCTP/IP) stack
*S1_U: GSRP Tunneling Protocol/UDP5/IP stack
May 31, 2012
Ken Baker (http://morse.colorado.edu/~kkbaker/)
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Pico-Cells … Heterogeneous Networks
Increasing data rate
requirements
• Need better SNR
Increasing capacity
requirements
• Need more cells
Ergo: Put cells where
the users are
• Trend is to complement
Picocells
• S1 interface for backhaul,
not ethernet
Picocells exist today in
3G networks
macro network with
picocells
• Possible with LTE Rel.8
• Enhancements with Rel. 11
May 31, 2012
Ken Baker (http://morse.colorado.edu/~kkbaker/)
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Relay Nodes
Donor eNB uses LTE as backhaul
Either in-band or out-of-band
Backhaul Link
(Un)
(Uu)
(Donor) eNB
RNB
Relay Node
Access Link
(Uu)
MUE
RUE
Macro UE
Relay UE
Donor Cell
May 31, 2012
Relay Cell
Ken Baker (http://morse.colorado.edu/~kkbaker/)
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Example Application: Public Safety
See: Order and Fourth Further Notice of Proposed Rule Making, FCC11-6, “In the Matter
of Service Rules for the 698-746, 747-762 and 777-792 MHz Bands; Implementing a
Nationwide, Broadband, Interoperable Public Safety Network in the 700 MHz Band;
Amendment of Part 90 of the Commission’s Rules,” January 25, 2011
May 31, 2012
Ken Baker (http://morse.colorado.edu/~kkbaker/)
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Outage Probability as a Function of No. of Relays
Ref. Tin-Ei Wang, unpublished work
May 31, 2012
Ken Baker (http://morse.colorado.edu/~kkbaker/)
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LTE Heterogeneous Networks
Network Elements
• Relays
• Pico Cells
• Femtocells (Home Node B)
Need tight coordination for Handover and
Interference management
•
•
Negative Impact at small cell edges
Small cells need handover management
May 31, 2012
Ken Baker (http://morse.colorado.edu/~kkbaker/)
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LTE Heterogeneous Networks
LTE Network Solutions:
• Soft Cell
• Enhanced Inter Cell Interference Coordination (eICIC)
• CoMP
• Self-Organizing Networks (SON)
• Dynamic Load Balancing
• Carrier Aggregation
May 31, 2012
Ken Baker (http://morse.colorado.edu/~kkbaker/)
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Enhanced Local Access: Soft Cell
In LTE Advanced:
Pico does not create a new cell but is an extension of
an overlaid macrocell
• Macro – basic coverage (system info, data, control
• Pico – enhanced capacity and data rates
Consider this a macro assisted pico layer
May 31, 2012
Ken Baker (http://morse.colorado.edu/~kkbaker/)
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Inter-cell Interference Coordination (ICIC)
Release 8 (LTE)
•
Interference mitigation by coordinating DL control
and data channels
• lowering the power of a part of the sub-channels in
the frequency domain
Release 10 (LTE-A)
• coordinate blanking of sub-frames in the time domain
in the macro cell
•
Only legacy broadcast signals and channels are
transmitted to support legacy Rel 8 UEs
May 31, 2012
Ken Baker (http://morse.colorado.edu/~kkbaker/)
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ICIC Rel. 8 SINR Distribution Example
Original
reuse
ICIC
Example
-5 dB
May 31, 2012
20 dB
Ken Baker (http://morse.colorado.edu/~kkbaker/)
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CoMP
Coordinated Multipoint Transmission
Increases Data Rate
•
coordinating and combining signals from multiple
antennas
May 31, 2012
Ken Baker (http://morse.colorado.edu/~kkbaker/)
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Rel. 10/11 CoMP
Downlink
• joint processing (JP)
• coordinated scheduling
(CS)
Uplink
• joint reception (JR)
• Coordinated scheduling
(CS)
• coordinated
beamforming (CB)
May 31, 2012
Ken Baker (http://morse.colorado.edu/~kkbaker/)
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Self-Optimizing Networks (SON)
“Self-Optimizing and Self-Configuring”
• Needed to manage tiers
Identified Use Cases:
• Energy Savings
• Interference Reduction
• Automated Configuration of Physical Cell Identity
• Mobility robustness optimization
• Mobility Load balancing optimization
• RACH Optimization
• Automatic Neighbor Relation Function
• Inter-cell Interference Coordination
3GPP TR 36.902 V9.3.1 (2011-03)
Note: HCS is not mentioned specifically in 36.902
May 31, 2012
Ken Baker (http://morse.colorado.edu/~kkbaker/)
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Dynamic Load Balancing
• Between tiers
• Listed as a function of the X2 interface:
“This function allows exchanging overload
and traffic load information between eNBs,
such that the eNBs can control the traffic load
appropriately. This information may be
spontaneously sent to selected neighbour
eNBs, or reported as configured by a
neighbour eNB.”
•
3GPP TS 36.420 V10.2.0 (2011-09)
May 31, 2012
Ken Baker (http://morse.colorado.edu/~kkbaker/)
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Carrier Aggregation
Between bands
Between tiers
May 31, 2012
Ken Baker (http://morse.colorado.edu/~kkbaker/)
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DAS or Femto?
Summary of solution comparison
Metric
Equipment + Labor
Costs1
Flexibility
Femto
DAS
Active DAS - $0.25 - $ 0.5
per sq. foot.
Medium,
Coverage should be planned
High, technology, coverage at once
and capacity can be added as Capacity can be modified
needed
through sectorization plan
Adding technology depends
on selected DAS
$.05-$.1 per sq. foot
Multi-operator
support2
Requires multiple Femtos
Deployment Model
Requires planning and
Plug and play solution, with
extensive deployment
limited setting for Enterprise
support (installation,
Femto
commissioning….)
Possible
1. ABIresearch
2. IBW Solution and Capacity Offload in 3G and LTE (IBW symposium)
May 31, 2012
Ken Baker (http://morse.colorado.edu/~kkbaker/)
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One Slide About Backhaul
•
•
The backhaul network needs to be able to
support the wireless throughput.
Backhaul is one of the major expenses for
wireless network operators
Max. 802.11b
May 31, 2012
Ken Baker (http://morse.colorado.edu/~kkbaker/)
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Motivations for HetNets
Better performance:
1. Better coverage
•
Chow, et. al, 1994
2. Better SNR
•
Madhusudhanan, et. al, 2011
Madhusudhanan, P.; Restrepo, J.G.; Youjian Liu; Brown, T.X.;
Baker, K.R.; , "Multi-Tier Network Performance Analysis Using a
Shotgun Cellular System," Global Telecommunications Conference
(GLOBECOM 2011), 2011 IEEE , vol., no., pp.1-6, 5-9 Dec. 2011.
May 31, 2012
Ken Baker (http://morse.colorado.edu/~kkbaker/)
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Challenges in Studying a Multi-tier Network
Simulation study of the entire
system is computationally
infeasible.
Ideal hexagonal grid model is
not a good model anymore.
Certain entities of the network
are essentially random in nature.
 e.g. the location of the
femtocell BSs.
May 31, 2012
Ken Baker (http://morse.colorado.edu/~kkbaker/)
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Motivations for considering a Shotgun Cellular
System Inspired Model
Shotgun Cellular System (SCS): [Brown 2000] The
cellular system where the BS placement is according
to a 2-D homogeneous Poisson point process.
SCS is a good model the femtocell BSs in the
network.
The SCS is a surprisingly good model for the
macrocell network:
 SCS provides a natural lower bound to the cellular
performance.
 [Brown 2000] The SCS model provides a fair idea about the
actual macrocell network.
 In the strong shadow fading regime, the downlink performance in
an SCS converges to ideal hexagonal grid model.
 In the normal shadow fading regime, the gap between the
downlink performance in an SCS and in an ideal hexagonal grid
model is small.
May 31, 2012
Ken Baker (http://morse.colorado.edu/~kkbaker/)
51
System Model
Multi-tier network with 𝑀 tiers of heterogeneous
networks.
Each tier is an SCS independent of the other
tiers.
 BS density: 𝜆𝑖 , ∀ 𝑖 = 1,2, … , 𝑀.
 BS transmission power: 𝐾𝑖 , ∀ 𝑖 = 1,2, … ,
 SINR threshold: Γ (same for all tiers)
𝑀.
Received power at a distance 𝑅 from a BS of
the 𝑖 𝑡ℎ tier is
𝑃𝑖
=
𝐾𝑖 Ψ𝑅−𝜀 , ∀ 𝑖 = 1,2, … , 𝑀.
Path-loss exponent
Shadow fading factor
Background noise - 𝑁.
May 31, 2012
Ken Baker (http://morse.colorado.edu/~kkbaker/)
52
Performance Metric
Carrier-to-Interference-ratio
origin
𝐶
𝐼
=
𝑀
𝑖=1
𝐶
𝐼
at the mobile user located at
𝐾𝑠 Ψ𝑠 𝑅𝑠−𝜀
−𝜀
∞
𝐾
Ψ
𝑅
𝑗=1 𝑖 𝑖,𝑗 𝑖,𝑗
‘s’ → the tier corresponding
to the strongest signal at the
MS
Total interference
power due to the rest
of the BSs in the
multi-tier network.
𝐶
Carrier-to-Interference-plus-noise-ratio 𝐼+𝑁
Problem:
For the multi-tier network, Characterize
the success probabilities: Prob
(or) the outage probabilities: Prob
May 31, 2012
𝐶
𝐼
𝐶
>Γ
𝐼+𝑁
𝐶
Prob 𝐼+𝑁 ≤ Γ
> Γ and Prob
𝐶
𝐼
≤ Γ and
Ken Baker (http://morse.colorado.edu/~kkbaker/)
.
53
Approach
𝐶
𝐼
• , 1-tier network, w/o shadow fading.
Step1
Step 2
•
𝐶
,
𝐼+𝑁
•
𝐶
, 1-tier network, arbitrary fading distribution.
𝐼
𝐶
, 1-tier network, arbitrary fading distribution.
𝐼+𝑁
•
•
Step 3
May 31, 2012
•
1-tier network, w/o shadow fading.
𝐶
, multi-tier network, arbitrary fading distribution.
𝐼
𝐶
, multi-tier network, arbitrary fading distribution.
𝐼+𝑁
Ken Baker (http://morse.colorado.edu/~kkbaker/)
54
Multi-tier Networks
Having thoroughly studied the single-tier network, we move on to the multitier network.
Multi-tier network with 𝑀 − tiers of independent SCSs, represented as 𝑀,
May 31, 2012
Ken Baker (http://morse.colorado.edu/~kkbaker/)
55
Multi-tier Networks:
Important Implications
Inclusion of the additional tiers of wireless network:
 Does not affect the
Improves the
𝐶
𝐼+𝑁
𝐶
𝐼
success probability.
success probability when
 There is no shadow fading.
2
𝜀
 The arbitrary shadow fading distribution is such that 𝐄 Ψ ≥ 1.
For example, log-normal shadow fading factors with 0 mean and
standard deviation 𝜎 satisfy the above condition.
May 31, 2012
Ken Baker (http://morse.colorado.edu/~kkbaker/)
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Madhusudhanan, et. al Conclusions
𝐶
𝐶
We have studied the 𝐼 and 𝐼+𝑁 success probability of a multi-tier
network by systematically reducing the network to equivalent
networks and finally to a single-tier network that we understand well.
As a result, for a multi-tier network where the SINR thresholds of all
the tiers are the same, we have
𝐶
𝐼
and
𝐶
𝐼+𝑁
𝐶
𝐼
success probability for SINR

Derived the semi-analytical expression for the
for SINR threshold Γ ≥ 0.

Obtained a simple closed form expression for
threshold Γ ≥ 1.

The above result matches the results obtained by [Dhillon, Ganti, Baccelli,
Andrews, 2011] and [Mukherjee, 2011] who approached the problem in
different ways with results restricted only to Rayleigh fading distributions.

Further, we have derived an approximation for the
show the approximation is tight.

All the results derived in the paper hold for arbitrary fading distribution.
May 31, 2012
𝐶
𝐼
success probabilities
success probability and
Ken Baker (http://morse.colorado.edu/~kkbaker/)
57
The Path From Today to HetNet
Indoor DAS
Outdoor DAS
Femtocells
Picocells
May 31, 2012
Soft Cells
Better Femtocells
Indoor / IP Connected
Ken Baker (http://morse.colorado.edu/~kkbaker/)
HetNets
SON
ICIC
CoMP
Relays
58
If I were a cellular network operator …
All Technology Decisions are Business driven
Future will be built upon combining networks
1) Entrenched equipment and technology will
drive future deployments
1) Capital investment to be fully effectuated.
2) Engineering staff that knows the current technology
cannot be redirected instantaneously
2) Leveraging technology to mitigate expenses
1)
WiFi off-load
May 31, 2012
Ken Baker (http://morse.colorado.edu/~kkbaker/)
59
Research Issues
Research Issues
• Backhaul
• Simulation of Indoor and Outdoor Network Interaction
• Improving Small Cell Handover and Control
• Managing Handover Between Tiers
• Managing Interference Between Tiers
• Taking SON Concepts Across Tiers
• Traffic steering
–
RAT handovers
–
layer handovers
–
resource availability
May 31, 2012
Ken Baker (http://morse.colorado.edu/~kkbaker/)
60
Bibliography (1/3)
P. Chow, A. Karim, V. Fung, and C. Dietrich. Performance
advantages of distributed antennas in indoor wireless
communication systems. In IEEE Proceedings of Vehicular
Technology Conference, 1994, volume 3, pages 1522 – 1526, June
1994.
Timothy X Brown, “Cellular performance bounds via shotgun
cellular systems”, IEEE Journal on Selected Areas in
Communications, vol. 18, no. 11, pp. 2443-2455, Nov 2000.
H. S. Dhillon, R. K. Ganti, F. Baccelli, J. G. Andrews, “Modeling and
analysis of K-tier downlink heterogeneous networks”, IEEE Journal
on Selected Areas in Communications, to appear in Apr 2012.
S. Mukherjee, “Downlink SINR distribution in a heterogeneous
cellular wireless network with max-SINR connectivity”, Allerton
Conference on Communication, Control, and Computing, Sep 2011.
Madhusudhanan, P.; Restrepo, J.G.; Youjian Liu; Brown, T.X.; Baker,
K.R.; , "Multi-Tier Network Performance Analysis Using a Shotgun
Cellular System," Global Telecommunications Conference
(GLOBECOM 2011), 2011 IEEE , vol., no., pp.1-6, 5-9 Dec. 2011.
May 31, 2012
Ken Baker (http://morse.colorado.edu/~kkbaker/)
61
Bibliography (2/3)
Blaze Vincent, Reverse Link Analysis and Modeling of CDMA based Distributed
Antenna Systems. Thesis (M.S.)--University of Colorado, Dec. 2011. See also
references therein.
Tin-Ei Wang, CU Boulder, unpublished work, 2012
Ching-Pu Wu, K. Baker, “Comparison of LTE Performance Indicators and
Throughput in Indoor and Outdoor Scenarios at 700 MHz,” to be published:
Proc. IEEE 76th Vehicular Technology Conference, VTC2012-Fall, Québec City,
Sept. 2012.
Christophe Chevalier, “Expanding 3G Coverage: Indoor and High Capacity
Venues,” Presentation material, Qualcomm Inc.
Jon M. Peha, et. al, “The Public Safety Nationwide Interoperable Broadband
Network: A New Model for Capacity, Performance and Cost,” FCC White Paper:
DOC-298799A1, June 2010. http://transition.fcc.gov/pshs/docs/releases/DOC298799A1.pdf
James Arden Barnett, Jr., Jennifer A. Manner, FCC Public Safety and Homeland
Security Bureau, Presentation to: 2010 UASI National Conference, New Orleans,
LA, June 22, 2010
S. Kishore, L. Greenstein, H. Poor, and S. Schwartz, “Uplink user capacity in a
CDMA macrocell with a hotspot microcell: exact and approximate analyses,”
IEEE Trans. Wireless Commun., vol. 2, no. 2, pp. 364–374, Mar. 2003.
——, “Uplink user capacity in a multicell CDMA system with hotspot microcells,”
IEEE Trans. Wireless Commun., vol. 5, no. 6, pp. 1333–1342, June 2006.
May 31, 2012
Ken Baker (http://morse.colorado.edu/~kkbaker/)
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Bibliography (3/3)
S. Kishore, L. J. Greenstein, H. V. Poor, and S. C. Schwartz, “Uplink user
capacity in a CDMA system with hotspot microcells: effects of finite
transmit power and dispersion,” IEEE Trans. Wireless Com., vol. 5, no. 2,
pp. 417–426, Feb. 2006.
Claussen, H., "Performance of Macro- and Co-Channel Femtocells in a
Hierarchical Cell Structure," Personal, Indoor and Mobile Radio
Communications, 2007. PIMRC 2007. IEEE 18th International Symposium on,
pp.1-5, 3-7 Sept. 2007.
Kaneko, M.; Popovski, P.; , "Radio Resource Allocation Algorithm for RelayAided Cellular OFDMA System," Communications, 2007. ICC '07. IEEE
International Conference on , vol., no., pp.4831-4836, 24-28 June 2007.
Chandrasekhar, V.; Andrews, J.; "Uplink capacity and interference
avoidance for two-tier femtocell networks," Wireless Communications, IEEE
Transactions on, vol.8, no.7, pp.3498-3509, July 2009.
“The Future of Hotspots: Making Wi-Fi as Secure and Easy to Use as
Cellular,” Cisco Whitepaper,
http://www.cisco.com/en/US/solutions/collateral/ns341/ns524/ns673/white_paper_c11-649337.html
May 31, 2012
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