Wireless Backhaul for 5G · LTE X2 and S1 Interfaces ... Performance of Wireless Backbone • 4G & Beyond backhaul requires to meet SLA performance criteria for – Availability –

Wireless Backhaul for 5GDr. Manodha Gamage

Founder/Managing DirectorISaC (Pvt.) Ltd – Sri Lanka

Consultant, Senior Lecturer & Trainer in Telecommunicationswww.isac.lk

[email protected]

Dynamic Broadband NeedsMobile Users Demand:• Very high Speeds• Seamless access of Large Volumes of Data• More Real Time & Video Applications• Very High Reliability & Scalability• Reductions in COST

Most used MobileBroadband Technology

by 2020 will be LTE

Dr. Manodha Gamage - ISaC (Pvt.) Ltd 2Ericsson Mobility Report –June 2016

Evolution - 2G/3G RAN to 4G RAN Architecture

RNC/BSC

2G&3G

Operator Actions:• Small Cells (Heterogeneous Networks)

• All IP Backhaul

Dr. Manodha Gamage - ISaC (Pvt.) Ltd3

LTE removed RNC/BSC andmade eNodeB more intelligent

eNodeB

LTE, LTE-A& beyond

5G Use Case Categories


LTE X2 and S1 InterfacesX2 interface supports communication between eNBs for:• Handover, Self Organized NWs (SON),• LTE Advanced features to:

• Control Interference• Increase Capacity

X2 interface:• Saves backhaul BW• Minimizing

communication delay

S1 Interface:• Reliability• Scalability

Require Close Cooperationamong cell sites

Dr. Manodha Gamage - ISaC (Pvt.) Ltd 5

X2 interface:• Saves backhaul BW• Minimizing

communication delay

S1 Interface:• Reliability• Scalability

Requirements of Backhaul beyond 4G• Meet Ever increasing Capacity needs of RAN

• Lower Latency &Tight Synchronization (IEEE 1588v2 – PTP)

• Support Heterogeneous RAN with Small Cells (SON)

• Need to minimize TCO (may be SDN, NFV etc.)


Backhaul Technologies Depend on….• Urban or Rural? (Population density??)

• Applications– Real time? Video? Interactive ? etc.

– Critical? Availability very important?

– Volumes of traffic

• Affordability (TCO)

• Importance of synchronization of CELLs

• Country Specifics????


• Urban or Rural? (Population density??)

• Applications– Real time? Video? Interactive ? etc.

– Critical? Availability very important?

– Volumes of traffic

• Affordability (TCO)

• Importance of synchronization of CELLs

• Country Specifics????

Backhaul Requirements for Dense Urban Areas• For MACRO base stations

– Expected capacity few Gbit/s per base station

– Hop lengths to reach an existing fiber connected point expected to be short(200 meters to 1 km)

• Outdoor Small Cells (Micro & Pico)– Should handle none line of sight environments

– Capacity requirements from 10 – 100s of Mbit/s

– Hop lengths to reach an existing fiber connected point expected to be shorter(Compared to macro base station case)

Dr. Manodha Gamage - ISaC (Pvt.) Ltd

8

• For MACRO base stations– Expected capacity few Gbit/s per base station

– Hop lengths to reach an existing fiber connected point expected to be short(200 meters to 1 km)

• Outdoor Small Cells (Micro & Pico)– Should handle none line of sight environments

– Capacity requirements from 10 – 100s of Mbit/s

– Hop lengths to reach an existing fiber connected point expected to be shorter(Compared to macro base station case)

Source: NGMN Alliance

Backhaul Requirements for Rural Areas

• No focus on network densification

• Hop lengths expected to be quite long - up to 15 km

• Low Capacity Requirement– Several 100s of Mbit/s

BackhaulFiber?Microwave?Copper?

As of Today around the worldthe BackhaulCu – Almost Nothing (less than 5%)Fiber & Microwave = almost 50:50


BackhaulFiber?Microwave?Copper?

As of Today around the worldthe BackhaulCu – Almost Nothing (less than 5%)Fiber & Microwave = almost 50:50

Fiber the BestBut NOT Feasible everywhere• High cost• Delays in deployment

Cost of Backhaul – Fiber Vs Microwave

Achieving 99.999% availabilityusing fiber is very expensive


Requirements of Backhaul for Front-haul Links• Traditional backhaul link

– End user data bits & System Control Information transmitted to & from BaseStations

• Front-haul - Connection between central unit (BBU) & Remote Radio Unit(RRU),

– Digital samples of signal transmitted & received at antenna increases bitrate offront-haul (multiple times compared to a traditional backhaul)

– Statistical Multiplexing of multisector sites reduces capacity need of backhaul – ButFront haul capacity needs increase linearly with number of sectors

– Multiple RRUs could be connected to one BBU/Control – hence more capacityneeded

• Front-haul capacity requirements in the range of 1-10 Gbit/s per RRU

– For MULTI sector site – should multiply with number of sectors

• Some applications could add additional requirements– Low latency and tight synchronization


• Traditional backhaul link– End user data bits & System Control Information transmitted to & from Base

Stations

• Front-haul - Connection between central unit (BBU) & Remote Radio Unit(RRU),

– Digital samples of signal transmitted & received at antenna increases bitrate offront-haul (multiple times compared to a traditional backhaul)

– Statistical Multiplexing of multisector sites reduces capacity need of backhaul – ButFront haul capacity needs increase linearly with number of sectors

– Multiple RRUs could be connected to one BBU/Control – hence more capacityneeded

• Front-haul capacity requirements in the range of 1-10 Gbit/s per RRU

– For MULTI sector site – should multiply with number of sectors

• Some applications could add additional requirements– Low latency and tight synchronization

Base Stations with Remote Radio Head

12

BBU

RRH

Front-haul & Backhaul


Front-haul towards 5G

Current C-RAN

2Gbps

10Gbps

BBU Pool

14

Future C-RANBBU Pool

3Gbps

Fiber Vs Microwave


Microwave can be used when Data Rate is 3 - 4Gbps

Performance of Wireless Backbone• 4G & Beyond backhaul requires to meet SLA performance criteria

for– Availability

– Packet delay

– Jitter

– Packet loss.

• Operators require 99.999% availability(approximately 5 minutes of down time per year)

• LTE SLA can be easily achieved by– Fiber-based backhaul (but would be very expensive)

– Line-of-Sight (LoS) microwave backhaul


• 4G & Beyond backhaul requires to meet SLA performance criteriafor– Availability

– Packet delay

– Jitter

– Packet loss.

• Operators require 99.999% availability(approximately 5 minutes of down time per year)

• LTE SLA can be easily achieved by– Fiber-based backhaul (but would be very expensive)

– Line-of-Sight (LoS) microwave backhaul

Low Frequency Bands (below 11 GHz)• Good propagation characteristics

• Support Long-haul hops(typically 10 - 50 km)– Can minimize sites

• Very important for mobilebroadband deployment– Rural Areas

– Fiber not technically oreconomically feasible.

• Useful for shorter hops withoutline-of-sight

• Ex: sub 6GHz, 11GHz


• Good propagation characteristics

• Support Long-haul hops(typically 10 - 50 km)– Can minimize sites

• Very important for mobilebroadband deployment– Rural Areas

– Fiber not technically oreconomically feasible.

• Useful for shorter hops withoutline-of-sight

• Ex: sub 6GHz, 11GHz

Mid-Range Frequency Bands (11 to 23/30 GHz)• Supporting medium-haul links (typically 8 - 20 km)

• Examples– 13GHz, 18GHz, 23GHz, 24GHz

• Larger RF channel bandwidths possible

• Suitable for IMT and other terrestrial mobile broadband systems inpopulated areas outside dense city centers– Suburbs

– Industrial parks etc.


• Supporting medium-haul links (typically 8 - 20 km)

• Examples– 13GHz, 18GHz, 23GHz, 24GHz

• Larger RF channel bandwidths possible

• Suitable for IMT and other terrestrial mobile broadband systems inpopulated areas outside dense city centers– Suburbs

– Industrial parks etc.

High Frequency Bands (above 23GHz)• Short-haul links (typically < 8 km)

• Offers very large transmission capacity & suitable for– High traffic requirements

– Mobile broadband systems deployed in dense urban areas

• Backhaul traffic Small Cells– Range is small but spectrum reuse capability is high

• Example Bands– 26 & 28 GHz

– 38 & 42 GHz

– 59 - 64 GHz,

– 64 – 66GHz

– 71-76/81-86 GHz

– 92 – 95 GHz


• Short-haul links (typically < 8 km)

• Offers very large transmission capacity & suitable for– High traffic requirements

– Mobile broadband systems deployed in dense urban areas

• Backhaul traffic Small Cells– Range is small but spectrum reuse capability is high

• Example Bands– 26 & 28 GHz

– 38 & 42 GHz

– 59 - 64 GHz,

– 64 – 66GHz

– 71-76/81-86 GHz

– 92 – 95 GHz

Strategies for Regulators• Maximize use of Fiber in Backhaul

– Encourage Sharing

– Competition

– Open & fair pricing

– Incentives to install fiber in less attractive rural areas

• Best use of Wireless (Microwave) Backhaul– Revisit existing Policies & Pricing models

• Low Freq Bands

• Mid-Range Freq Band

• High Freq Bands

– Make sure the correct freq. band is used for the correct application

• Can you impose conditions instead a FEE ??

• Consider NFV, SDN etc.


• Maximize use of Fiber in Backhaul– Encourage Sharing

– Competition

– Open & fair pricing

– Incentives to install fiber in less attractive rural areas

• Best use of Wireless (Microwave) Backhaul– Revisit existing Policies & Pricing models

• Low Freq Bands

• Mid-Range Freq Band

• High Freq Bands

– Make sure the correct freq. band is used for the correct application

• Can you impose conditions instead a FEE ??

• Consider NFV, SDN etc.

Conclusion

• Need a Flexible Backhaul

• Optical Fiber Preferred…….. but Wireless would co-exist– Due to Technical and Financial non-feasibility


• Need a Flexible Backhaul

• Optical Fiber Preferred…….. but Wireless would co-exist– Due to Technical and Financial non-feasibility

Thank You


www.isac.lk

Backhaul with Microwave

Small Cell Sites Microwave Hub Sites Fiber/Microwave Hub site


Documents

Wireless Backhaul for 5G · LTE X2 and S1 Interfaces ... Performance of Wireless Backbone • 4G & Beyond backhaul requires to meet SLA performance criteria for – Availability –