TD-

Dense RAN: Handling Interference in a
Dense City Environment
GTI workshop, Tokyo
Dr. Phil Fleming, Head of Radio Technology & Engineering

1© Nokia Siemens Networks

NSN Concepts for High Density City Environment
Stadiums are challenging venues that test
wireless data systems
The solutions depend on the penetrationof smartphones and the density of the crowd• Light to medium
Add more macrocell capacity• Medium to heavy
Macros and picocell clusters over ethernet• Heavy++ loadDense RAN using Macros/picos andPicoRRH over fiber w/BB pooling to eliminate the cell edge2© Nokia Siemens Networks 2011

Spectrum of Architectures
to Supplement Macrocells and Eliminate the Cell Edge
Flexi Zone
AP 6

FZ AP 1NLOSFZ AP 1NLOSFZ AP 8NLOSFZ AP 1NLOS

Low TCO Indoor Solution

FZ AP 7NLOSFZ AP 1NLOSEnterprise LANEPCInternet
WAN& ent. Internet

Looking SW from Macro AP-Cluster 12-15
antenna on 200N

AP

AP

AP

Controller

Dense RAN

IndoorAPAP

Fiber-Interconnect
Dense AP/RRH<1ms latency

Flexi Zone
controller

Urban StreetAPIP Backhaul;
In-building/Enterprise
Wiring, Network(CAT5, Switching/Routing)
Latency ~10ms

Ethernet

IP Backhaul;
Delay Tolerant >10ms
Including Wireless

OffloadController

APAPAP
AP

OffloadTransport

Transport

CoreCoreController

APAP

OffloadTransportCoreincreasing user density
DistributedScheduler
Packet-based Coordination

Ethernet/Wireless BH + picoAP3© Nokia Siemens Networks 2011

Centralized scheduler
Joint Receiver/Transmitter

Fiber + picoRRH

Dense RAN solutions• Stadiums have the densest population of smart phones in the world• Up to 100,000 fans sending videos to friends and watching highlights on Youtube• Many small (unobtrusive) low power cells over fiber or Ethernet

64 cells in a 300x200 m2 stadium 1000 cells/km2!
4© Nokia Siemens Networks 2011

The user’s signal quality degrades as more cells are added tothe stadium

5© Nokia Siemens Networks 2011

The user’s signal quality degrades as more cells are added tothe stadium

6© Nokia Siemens Networks 2011

The Interference Dimensionality Problem
Stadium capacity
increases with morecells but notproportionallyDense user population
Dense cells
More interference andMore interferers!
Higher Interference Dimension
20 MHz TD-LTE

Cell edge throughput
decreases with morecells

7© Nokia Siemens Networks 2011

Cell-edge

eliminated!

Comparison of Stadium Dense RAN Uplink Methods

itCapac8© Nokia Siemens Networks 2011

with Dselacysens

methNAReods

Elimination of the cell edge on the uplink
CoMP
CoMP (Static)(Static)

Throughput in Mbps

Independent
Independent cells
cells

CoMP
CoMP (Dynamic)(Dynamic)

Many users
have Tput <0.5 Mbps

All users
have Tput >1.5 Mbps

9© Nokia Siemens Networks 2011

CoMP
CoMP (Dynamic,(Dynamic, Advanced
Advanced Joint
Joint Rx.)
Rx.)

Downlink without Dense RAN
Low throughput
users

High throughputusers

In 32-sector stadium system, the low throughput users cluster on the cell edge

10

© Nokia Siemens Networks 2011

ArrayComm Confidential ProprietaryDownlink with Dense RAN
Dense RAN transmission algorithms leverage the reciprocity of TD-LTEFewer low throughput users that are clustered in the outer rim of the CoMP set
Dense RAN will use overlapping CoMP sets to eliminate the cell-edge
Bottom 10% throughput users’ location distribution

11© Nokia Siemens Networks 2011

ArrayComm Confidential ProprietaryDownlink Dense RAN Throughput comparison

8 cells

16 cells
32 cells
64 cells

12© Nokia Siemens Networks 2011

ArrayComm Confidential ProprietarySummary
NSN has Dense RAN solutions for both UL and DL• Pico clusters using advanced joint reception and transmission algorithms• Advanced architectures enabling overlapping CoMP groups of cells

Dense RAN Solutions designed for and evaluated in the mostchallenging ultra-dense venues in the world: Stadiums
Dense RAN efficiently handles high interference venues byeliminating the cell edge using overlapping clusters

13© Nokia Siemens Networks 2011

ArrayComm Confidential Proprietary