1 © Nokia Siemens Networks

Dense RAN: Handling Interference in a Dense City EnvironmentGTI workshop, TokyoDr. Phil Fleming, Head of Radio Technology & Engineering

TD-

2 © Nokia Siemens Networks 2011

NSN Concepts for High Density City Environment

• Light to medium Add more macrocell capacity• Medium to heavy Macros and picocell clusters over ethernet• Heavy++ load Dense RAN using Macros/picos and PicoRRH over fiber w/BB pooling to eliminate the cell edge

Stadiums are challenging venues that test wireless data systems

The solutions depend on the penetration of smartphones and the density of the crowd

3 © Nokia Siemens Networks 2011

Fiber + picoRRH

DistributedSchedulerPacket-based Coordination

Spectrum of Architectures to Supplement Macrocells and Eliminate the Cell Edge

Offload

AP

Core

Controller

AP

Transport

AP

AP

Low TCO Indoor SolutionEthernet

Enterprise LAN

EPCInternet

WAN & ent. Internet

Flexi Zone controller

Flexi Zone AP 6

Looking SW from Macro antenna on 200N

FZ AP 1 NLOS

FZ AP 7 NLOS

FZ AP 1 NLOS

FZ AP 1 NLOS

FZ AP 8 NLOS

FZ AP 1 NLOS

Offload

AP

Core

Controller

AP

Transport

AP

APOffload

AP

Core

Controller

AP

Transport

AP

AP

IP Backhaul;Delay Tolerant >10msIncluding Wireless

AP-Cluster 12-15

IP Backhaul;In-building/EnterpriseWiring, Network (CAT5, Switching/Routing)Latency ~10ms

Urban Street Indoor

increasing user density

Dense RAN

Fiber-Interconnect Dense AP/RRH<1ms latency

Ethernet/Wireless BH + picoAP

Centralized schedulerJoint Receiver/Transmitter

4 © Nokia Siemens Networks 2011

Dense RAN solutions

64 cells in a 300x200 m2 stadium 1000 cells/km2!

• 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

5 © Nokia Siemens Networks 2011

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

6 © Nokia Siemens Networks 2011

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

7 © Nokia Siemens Networks 2011

The Interference Dimensionality Problem

Cell edge throughput decreases with more

cells

Stadium capacity increases with more

cells but not proportionally

Dense user population Dense cellsMore interference and More interferers!Higher Interference Dimension

20 MHz TD-LTE

8 © Nokia Siemens Networks 2011

Comparison of Stadium Dense RAN Uplink Methods

Cell-

edge

elim

inat

ed!

Capacity scales with Dense RAN methods

9 © Nokia Siemens Networks 2011

Elimination of the cell edge on the uplink

Thro

ughp

ut in

Mbp

s

Independent cellsIndependent cells CoMP (Static)CoMP (Static)

CoMP (Dynamic)CoMP (Dynamic) CoMP (Dynamic, Advanced Joint Rx.)CoMP (Dynamic, Advanced Joint Rx.)Many users have Tput <

0.5 Mbps

All users have Tput >

1.5 Mbps

10 © Nokia Siemens Networks 2011 ArrayComm Confidential Proprietary

Downlink without Dense RAN

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

High throughput users

Low throughput users

11 © Nokia Siemens Networks 2011 ArrayComm Confidential Proprietary

Downlink with Dense RAN

Bottom 10% throughput users’ location distribution

Dense RAN transmission algorithms leverage the reciprocity of TD-LTEFewer low throughput users that are clustered in the outer rim of the CoMP setDense RAN will use overlapping CoMP sets to eliminate the cell-edge

12 © Nokia Siemens Networks 2011 ArrayComm Confidential Proprietary

Downlink Dense RAN Throughput comparison

8 cells

16 cells

32 cells

64 cells

13 © 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 most challenging ultra-dense venues in the world: Stadiums

Dense RAN efficiently handles high interference venues by eliminating the cell edge using overlapping clusters