C4-1.8.4_Efficient Refarming of Spectrum with NSN Optimized Solution.pdf

NSN Response to Telkomsel RFP for NG TINEM

Efficient Refarming of Spectrum with NSN Optimized Solution

1. Introduction Mobile broadband demand continues to rise exponentially around the world. The demand for this service far outstrips the currently available spectrum for delivering this service.

As depicted below, the current operator spectrum pool will be unable to cope with the growing demand of mobile broadband unless the usage of existing spectrum is optimized or new spectrum is obtained.

Technical Package Attachment

C4-4.6.2 Efficient Refarming with NSN Optimized Solution NSN Response to Telkomsel RFP for NG TINEM (Copyright 2011 Nokia Siemens Networks. All rights reserved)

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Acquisition of new spectrum is dependent on regulatory policy and usually comes with a high price tag. This makes refarming of existing spectrum for use with more efficient technologies a more viable option in the near term for meeting the growing demand. In Telkomsel, besides with existing 900MHz, 1800Mz and 2100Mz, there is a plan to acquire new license in 700MHz, 850MHz, 2300MHz and 2600MHz, subjected to market environment and regulatory approval.

2. Refarming Trends Refarming is largely driven by the need to move to technologies which provide far more efficiency in the existing spectrum over older generation technologies. Moving from existing 2G spectrum to WCDMA or LTE provides >100% efficiency.



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3GPP and most of the global operators have identified use cases for specific bands which have also lead to the device ecosystem to be developed in step with the market need. Use of lower frequencies for radio access coverage building is beneficial due to better signal propagation. This leads to remarkably less base station sites and thereby to significantly reduced OPEX and CAPEX for an operator. Today the 900/1800MHz spectrum is very often already used by GSM. This makes the WCDMA/LTE deployment to these bands challenging. As operators naturally want to serve also their existing GSM subscribers the available spectrum needs to be divided between GSM and WCDMA/LTE networks. The challenge is how to successfully accommodate WCDMA/LTE into frequency band that is currently used by GSM, and at the same time keep the GSM capacity and quality unchanged. Terminal availability and penetration are important for refarming feasibility. First device for U900/L1800 are already available and more are coming. According to GSA report (Sept, 2012), a total of 978 UMTS900 and 98 LTE1800 user devices across all categories (Smartphone, dongles, router and tablets) were confirmed as having been officially announced by manufacturers, including carrier and frequency variants. From these devices, 96 of them can support both U900 and L1800 simultaneously.

3. Current Telkomsel Spectrum Situation Below diagram show the possible frequency scenario in Telkomsel by 2015. a. New spectrums: 2.3GHz for TD-LTE; 2.6GHz for FD-LTE; 850MHz for UMTS; 700MHz for APT-LTE b. Evolve spectrum: Additional two carriers bandwidth in UMTS2100 c.

Refarmed spectrums: GSM900 for UMTS900; GSM1800 for LTE1800



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In this paper, we will focus on U900 and L1800 refarming. Below are the available 900 and 1800 spectrum in Telkomsel network: •

GSM900: o

•

2 x 7.5MHz (Uplink: 900 – 907.5MHz; Downlink: 945-952.5MHz)

GSM1800: o

2 x 7.5MHz (Uplink: 1722.5 – 1730MHz; Downlink: 1817.5 – 1825MHz)

o

2 x 5MHz (Uplink: 1745 – 1750MHz; Downlink: 1840 – 1845MHz)

o

2 x 10MHz (Uplink: 1765 – 1775MHz; Downlink: 1860 – 1870MHz)

4. U900/L1800 Refarming a. U900 Refarming i. •

U900 refarming Value propositions:

Network costs for HSPA coverage at 900 MHz can be only about one third compared to the costs for HSPA coverage at 2100 MHz



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• • •

Especially attractive for rural area HSPA coverage Better indoor coverage in urban areas (10 .. 20 dB) Possible to reuse existing GSM900 sites and infrastructure

ii. • • • • •

U900 Refarming in Telkomsel:

Required 900MHz bandwidth: 3.8MHz (from the available 7.5MHz) Enabled by advanced narrower design of Flexi filter. Up to -66 dBm GSM uplink blocker can be tolerated, hence higher GSM interference (up to 22-24 dB) can be tolerated Supported with standard UEs Slight degradation (10% capacity loss) on refarmed U900 network compared with standard UMTS 4.2MHz Carrier Separation: GSM – GSM: 0.2 MHz; WCDMA – GSM: 2.0MHz



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b. L1800 refarming i. • • • • • •

L1800 coverage area about 2x larger than LTE2600. Possible to reuse antenna lines of UMTS2100 or GSM1800. Possible to deploy multi-RAN BTS with simultaneous LTE&GSM. 1800 MHz (ITU band 3) widely available in Telkomsel network Not big regulatory issues: 1800 band often technology neutral. Often easier to refarm than 900 MHz

ii. •

•

L1800 value propositions

L1800 refarming in Telkomsel

To refarm on the existing 2x10MHz on band (Uplink: 1765 – 1775MHz; Downlink: 1860 – 1870MHz) for L1800 o 2013 with 5MHz o 2014 onwards with 10MHz Spectrum required for coordinated case (share site) o 5 MHz needs 5.2MHz (in Downlink) o 10 MHz needs 9.6MHz (in Downlink)



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• • •

capacity same as with normal LTE 5MHz and 10 MHz Closest frequencies at both sides of the LTE carrier recommended to be used for GSM nonBCCH carriers (with power control) Carrier Separation: o GSM – GSM: 0.2 MHz; o LTE – GSM: 2.6 MHz (for 5MHz refarming, co-ordinated case) o LTE – GSM: 5.1MHz (for 10MHz refarming, co-ordinated case)

c. Capacity compensation after refarming There is one important challenge need to be addressed with refarming. Refarming will mean reduced spectrum for GSM. How to provide enough capacity with reduced spectrum to serve the GSM traffic after refarming?



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To compensate the loss in GSM capacity due to to refarming, Nokia Siemens Networks propose OSC to be used to quadruple the GSM capacity by software. Orthogonal Sub Channel (OSC) serves 4 users in the same GSM timeslot

The OSC feature’s greatest asset is its ability to double radio capacity, enabling enabling operators to efficiently exploit and even reduce installed hardware. With the trunking effect, the OSC could bring even greater gains to smaller BTS configurations. As the OSC increases voice capacity, it also frees up capacity for data traffic. The OSC also increases spectral efficiency measured in Erl/MHz/cell, especially when the number of carriers is restricted in the available spectrum. Simulations show that the OSC reduces per-Erlang per Erlang energy consumption by 20 to 50%. Last but not least, deploying the OSC successfully requires mobile handsets that support SAIC. Estimates put the total number of such devices on the market today at about with penetration ~50% (Source: Yankee Group 2009),, Telkomsel can benefit immediately by introducing the OSC. From Telkomsel OSC trial, TCH traffic at BANDARAKPG2MD3 increased by 27% after OSC activation and at the same time TCH blocking rate was reduced.


C4-4.6.2 4.6.2 Efficient Refarming with NSN Optimized Solution NSN Response to Telkomsel RFP for NG TINEM (Copyright Copyright 2011 Nokia Siemens Networks. All rights reserved)

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d. Base Station evolution After refarming, the traditional cabinet type base stations will be replaced with small size, modular Flexi Multiradio10 base station from Nokia Siemens Networks. Existing Dual-band antenna and feeders will be reused for GSM900/1800. For L1800, a new 2-port antenna will be used. Below diagram show the BTS site after U900 and L1800 refarming.

e. Mobility between layers and layering strategy After the refarming, Telkomsel will have to maintain a multi-layer network with different technologies (GSM/UMTS/LTE) and frequencies (900/1800/2100). In such heterogeneous networks (HetNets), end users are moving and expecting constant network availability and full service continuity. Besides, smooth transitions between different technologies when UEs are being in idle mode or coverage or service limited should be available. In the case of congestion, there should be a mechanism to offload between layers to ensure the network to run much more efficiently (traffic steering and load balancing). In Nokia Siemens networks, all the necessary mobility between layers will be offered to Telkomsel. Below figure shows the summary of the available mobility in Telkomsel HetNets.



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The objective of the layering strategy is to ensure seamless interworking between all frequency bands and layers that maintains end user quality of experience. The proposed strategy: • • • •

• •

f.

To keep U900 capable UEs camping on U900 most of the time Voice call preferred on U900 layer; dongle preferred on U2100 layer; Fast moving UE on U900 layer To use G900 voice calls only in case absolutely needed (i.e. neither G1800, U900 nor U2100 coverage available) To actively push UEs from U900 to U2100 when U2100 coverage is good enough to offload U900 traffic to U2100 (since there are more carriers in U2100). Load Balancing within U900 and U2100 bands possible To keep U2100 Carrier 1 for R99&HSPA; UMTS carrier 2 and 3 preferred HSPA; U2100 carrier 4 for small cell eg. Femto To keep L1800 capable UEs camping on L1800 most of the time. CSFB to UMTS/GSM when out of coverage. Another option is to use VoIP with IMS, then CSFB is not needed

Interference mitigation

For the 900 limited band like Telkomsel, the same frequencies have to be re-used .There is a possible co-channel interference when these layers are using the same frequency within the same geographical area. If not controlled, it may decrease the network performance significantly.



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To mitigate such interference, Nokia Siemens Networks propose to implement “Buffer Zone”. In the Buffer Zone, a chosen frequency will not be reused, effectively created a buffer zone between two areas using the same frequency band. Similar concept applies for both U900 and L1800 refarming. The method has been used to calculate the interference analysis between UMTS900 and GSM900 (or LTE1800 and GSM1800) in the case of Co-channel Co channel Interference is the MCL (Minimum Coupling Loss) approach. The Minimum Coupling Loss (MCL) is defined as the minimum distance loss including antenna gain measured between antenna connectors where we assume that the total interfering power should equal the thermal noise floor o of the victim system. This allows us to calculate a link-loss link loss from the interferer to the victim system.

Typical buffer zone distance: • •

GSM900: 15Km to 30Km (worst case) GSM1800: o With 5MHz refarming: 6Km-6.6Km 6Km (worst case); o With 10Mhz refarming: 5Km-5.3Km (worst case)

The buffer zone distance can be reduced by: • • •

correct frequency plan for GSM network lower antenna heights and tilting of GSM networks Lower number of GSM TRX


C4-4.6.2 4.6.2 Efficient Refarming with NSN Optimized Solution NSN Response to Telkomsel RFP for NG TINEM (Copyright Copyright 2011 Nokia Siemens Networks. All rights reserved)

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g. Fragmented 1800MHz bands rearrangement proposal As stated in Chapter 4 – Technical Specifications and Requirement, Clause 4.6.3, Telkomsel would like to have a proposal of rearrangement of their currently fragmented bands in 1800MHz. Nokia Siemens Networks is proposing below spectrum rearrangement for 1800MHz as shown in below figure. After the rearrangement, Telkomsel 1800MHz should try to get the spectrum for one end of 1800Mz band. Nokia Siemens Networks proposes to get 1857.5MHz to 1880MHz (22.5MHz contiguous band). The center frequency for LTE1800 should also be the center of the band (1868.75MHz). The advantage of getting the whole 1800MHz band on one side is to reduce the possible interference since only one end is directly interfering the other operator 1800MHz frequency band.

The effort and cost involved in such rearrangement exercise are: • • • •

Possible fee from regulator for rearrangement exercise Possible resistance from existing operator to change their existing allocation; as there will be impact Neighbors re-planning for all existing GSM1800 site All the existing GSM1800 BTS new center frequency to be retuned



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5. Nokia Siemens Networks Experience in refarming 1) U900 refarming capability Below are the highlights of Nokia Siemens Networks U900 refarming capabilities:

NSN – highlights for deployment on 900MHz spectrum 3.8 & 4.2 MHz WCDMA/HSPA solutions

Unique GSM spectral efficiency features: DFCA&OSC

Feasibility of 3G refarming in narrow spectrum allocation: -> more remaining GSM spectrum in parallel to WCDMA/HSPA supporting continuous 2G voice revenue generation

OSC: 2x voice capacity vs. AMR-HR (4users per GSM time-slot) AMR HR

OSC-HR

Half Rate voice codec

Dual Half Rate voice codes

A

4.2 MHz

A QPSK Transmitter

WCDMA De/Multiplexing

WCDMA Deployment on just 4.2 MHz bandwidth without performance degradation

Encoding Encoding

B A

B MIMO Receiver

Decoding Decoding

B

3.8 MHz

2 users per TSL

WCDMA

Refarming tools & track-record 900 MHz refarming

4 users per TSL

OSC principles

Ready ecosystem for WCDMA/HSPA-900

World-leading experience from world‘s first WCDMA/HSPA- 900 MHz refarming project with Elisa – in commercial service since 2007 NetAct Optimizer tool for optimizing GSM & WCDMA/HSPA – 900 performance

700 terminals in all device categories & price points (GSA) support tri-band WCDMA,HSPA-850/1900/2100

WCDMA/HSPA for 900 MHz rich device ecosystem

According to GSA report (August, 2012), there are currently 44 UMTS900 commercial networks in 33 countries. Nokia Siemens Network is supplying U900 solution to 40 customers where 28 of them have commercially launched the networks. Below figure shows Nokia Siemens Network U9000 refarming references:



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2) L1800 refarming capability Below are the highlights of Nokia Siemens Networks L1800 refarming capabilities:

NSN – highlights for deployment on 1800MHz spectrum Flexi remote RF - Full 80W power for GSM

Unique GSM spectral efficiency features: DFCA&OSC OSC: 2x voice capacity vs. AMR-HR (4users per GSM time-slot)

Full 60W power available for optimum GSM performance

AMR HR

240 W Flexi 180 W RF Module

OSC-HR

Half Rate voice codec

Dual Half Rate voice codes

A

80 W Tx1/RX1 LTE 60 W

A QPSK

80 W Tx2/RX2 LTE 60 W

Transmitter

De/Multiplexing

MIMO Receiver

2 users per TSL

4 users per TSL

B

Decoding Decoding

B

OSC principles

Optimum GSM & LTE performance Independent tilts for GSM & LTE ; dedicated bands

Encoding

A

B

Tx3/RX3 GSM 60 80 W W RX3div

Encoding

NSN customers – leading LTE 1800MHz deployment

Max. flexibility from spectrum allocation over the full 75 MHz bandwidth Independent optimization of antenna tilts 4-port or

2 X-pol

[W / MHz]

rG Tilt fo

WCDMA/ LTE f1 f2 f3 f4

6 GSM TRXs in 20 MHz

5Mhz 5Mhz 5Mhz 5Mhz

max 20 MHz Max 75 MHz BW (1800 MHz 3GPP band 3)

T

SM

r LT ilt fo

Antenna

C E/W

A DM

for Sector

Denmark, Finland, …

1

Finland …

Germany, Croatia, …

Frequency Latvia

Optimum GSM & LTE performance

Australia

South Korea

Live commercial LTE-1800 operation today

LTE for 1800 MHz – specifically on bandwidth of 2x10 MHz or more (beyond GSM needs)

Currently Nokia Siemens Networks has 21 references networks with LTE1800, where 13 of them (out of total 32 commercial networks) have commercially launched the network. Below figure shows Nokia Siemens Network U1800 refarming references:



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6. Why refarming with Nokia Siemens Networks As a leading vendor in SingleRAN, Nokia Siemens Networks can offer a holistic approach for efficient technology evolution for Telkomsel including U900 and L1800 frequency refarming based on truly SDR platform (Flexi Multiradio and multi-controller).

Why NSN ? – Nokia Siemens Networks SingleRAN Solution Site solution Network management

Network architecture

NetAct

High performance site SON

GSM/EDGE & HSPA

I-HSPA & LTE

BS

BS

BSC/RNC SGSN GGSN

&

GW

GSM HSPA LTE

Flexi Multiradio BTS Multicontroller Platform

LTE/LTE-A Capacity

High capacity transport

Short Latency

HSPA/HSPA+ QoS Battery Life

LTE FDD/TDD Refarming New bands Bandwidth flexibility

Efficient Spectrum Usage

Seamless software evolution

A holistic approach for efficient technology evolution

As proven leader in Frequency Refarming, Nokia Siemens Networks offers Telkomsel a thorough consultation process before implementing any solution to ensure we fully understand your business situation, opportunities and challenges. Working collaboratively we can model your business and help you see the impact of different technical options. Together, we can quickly improve your performance and results.



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C4-1.8.4_Efficient Refarming of Spectrum with NSN Optimized Solution.pdf

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