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1、EricssonMicrowaveO 20222Ericsson Microwave Outlook|October 2022Key contributorsExecutive Editor:Git Sellin Editor:Maria EdbergArticles:Andreas Olsson Bjrn Welander Gustav Rydn Jonas Flodin Jonas Hansryd Magnus Nilsson Maria Edberg Mikael Coldrey Mikael hberg Sren Axelsson5G is continuing to grow at

2、an impressive rate.By the end of 2021 more than 210 communications service providers had launched commercial 5G services,and the 5G share of mobile network traffic is expected to be 60 percent by 2027.Backhaul networks will need to be able to cater for high bandwidths to support 5G,but also to be fl

3、exible to serve the large variations in different markets and deployment types.Over the last 5 years,E-band has increased by an impressive 500 percent,to 6 percent of the total installed microwave base,proving to be a key player for 5G backhaul.E-band is now also available in India,and the usage of

4、E-band will continue to grow globally in coming years,reaching 25 percent of new deployments in 2027,with both standalone and multi-band solutions.In 2023,the upper 6 GHz band is up for consideration as a future 5G NR band.Since 6 GHz is a vital fixed service band for rural application,it is imperat

5、ive to coordinate those links on a national level with 5G in countries where this band is used for fixed service.The use of carrier aggregation in long haul systems makes it possible to increase capacity by around 50 percent Executive summaryThe continued strong growth of 5G puts a focus on power ef

6、ficiency and maximizing capacity in spectrum-limited networks.with the same number of radios.This is especially useful when only narrow channels are available,achieving increased capacity with the same availability,while reducing hardware footprint,power usage and total cost of ownership compared to

7、 a traditional system.This will help build high-capacity transport solutions for 5G in rural areas.Aggressive channel reuse enables up to double the peak capacity in dense networks with limited spectrum.As little as 5 to 10 degrees angular antenna separation can be sufficient to suppress interferenc

8、e,and at 30 to 50 degrees full peak capacity is achieved.Microwave radios have become 50 times more energy efficient over recent decades,on the basis of energy used per transported bit.With functionalities like traffic-aware output power and deep sleep,where the microwave network adapts energy consu

9、mption to meet momentary traffic demand,we can push the energy efficiency curve even further.A case study of a live network shows up to 20 percent energy savings over 5 years,using traffic-aware output power and AI-powered deep sleep functionality.Contents02 Executive summary03 Backhaul capacity evo

10、lution04 Spectrum in a dynamic market 07 Maximizing capacity in spectrum-limited networks10 How to reduce power consumption in microwave networks14 The rural challenge for 5G backhaul2Ericsson Microwave Outlook|October 2022Key contributorsExecutive Editors:Git Sellin Maria EdbergArticles:Andreas Ols

11、son Bjrn Welander Gustav Rydn Jonas Flodin Jonas Hansryd Magnus Nilsson Maria Edberg Mikael Coldrey Mikael hberg Sren Axelsson3Ericsson Microwave Outlook|October 20225G continues to see strong growth,with more than 210 service providers having launched commercial 5G services1 and over 20 5G standalo

12、ne(SA)commercial launches by the end of 2021.2 Latest forecasts for 2027 have the 5G share of mobile subscriptions at 48 percent2 and the 5G share of mobile network traffic at 60 percent.2 Mobile chipsets continue to evolve towards higher UE peak rates and are expected to reach 1520 Gbps by 2027.Typ

13、ical backhaul capacity requirements for distributed RAN sites are shown in Figure 1.Capacity variations,between and within markets and deployment types,continue to be large.This is mainly driven by the amount and type of spectrum operators have available and choose to deploy,but also by RAN spectrum

14、 aggregation features.As an example,serving a 3-sector 20 MHz 4-layer NR low-band spectrum requires approximately 500 Mbps backhaul capacity,while serving a 3-sector 100 MHz 8-layer NR mid-band requires approximately 3.5 Gbps.Operators are continuously updating their spectrum plans pending governmen

15、tal spectrum approvals and auctions.The changes forseen in a 2025 to 2027 timeframe include both mid-band(FR1)and high-band(FR2).Changes in backhaul capacities compared to what was indicated in the 2020 edition of the Microwave Outlook report are relatively small due to uncertainties about actual sp

16、ectrum releases and deployment,with some adjustment in the 2025 numbers and a slight increase to 2027.Increased deployment of Fixed Wireless Access(FWA)will further boost capacities in selected suburban and rural areas,increasing the required backhaul capacities.This is not included in the table in

17、Figure 1.Backhaul transport networks will need to cater for high bandwidths,but also be flexible to serve the large variations in different markets and deployment types.Backhaul capacity evolutionA steady growth in backhaul capacity is being driven by continued strong 5G growth,with large variations

18、 in different markets and deployment types.1 GSA(May 2022)2 All subscription,traffic and commercial 5G SA launch information is from the Ericsson Mobility Report,June 2022Figure 1:Backhaul capacity per distributed site2022450 Mbps 3 Gbps150 Mbps 350 MbpsUrban20252027SuburbanRural3G/4G and selective

19、5G3G/4G and ubiquitous 5GUrbanSuburbanRural250Mbps-500Mbps250Mbps-500Mbps250Mbps-500Mbps250Mbps-500Mbps250Mbps-500Mbps3 Gbps 10 Gbps500 Mbps 3 Gbps200 Mbps 1 Gbps5 Gbps 20 Gbps1 Gbps 5 Gbps300 Mbps 2 Gbps500 Mbps 2 Gbps1 Gbps 7 Gbps75 Mbps 250 Mbps200 Mbps 1 Gbps250Mbps-500Mbps250Mbps-500Mbps250Mbps

20、-500Mbps250Mbps-500Mbps250Mbps-500Mbps3 Gbps 15 Gbps700 Mbps 5 Gbps300 Mbps 1 Gbps7 Gbps 25 Gbps2 Gbps 10 Gbps500 Mbps 2 GbpsFigure 2:Distributed sites with backhaul connectivityCore siteVRAN siteCUVRAN siteDUDRAN siteF1CPRI/eCPRIeNB/gNBNG/Xn,S1/X2NG/Xn,S1/X2NG/Xn,S1/X2Distributed sites with backhau

21、l connectivityAntenna siteCRAN siteeNB/gNB4Ericsson Microwave Outlook|October 2022Figure 3:Global and regional view on used microwave spectrum including 5G impact on backhaul spectrumToday there are around 10 million transceivers installed for backhaul around the world.Figure 3 describes regional us

22、age of microwave spectrum,where the size of each circle represents the installed base.One of the biggest findings in this updated report is that compared to five years ago,the installed base of E-band(70/80 GHz)has grown from 1 percent and is now around 6 percent of the total installed base.This put

23、s it on a par with 38 GHz,a high-volume band for 20 years.Usage of E-band will continue to grow in coming years with both standalone and multi-band deployments.Spectrum in a dynamic market Microwave spectrum is a key 5G transport asset.In recent years,we have seen shifts in frequency use,the introdu

24、ction of 5G NR in traditional microwave bands,and development of E-band into a high-volume band.What trends do we see now and for coming years?Other bands that have grown over past years are the 32 GHz band,which will take over some deployments from 26 and 28 GHz when being repurposed for 5G New Rad

25、io(NR),and 6 and 11 GHz which continue to grow due to increasing rural capacity demands.There has also been a significant increase of 13 GHz links in India.Of the bands identified for IMT(International Mobile Telecommunications)at the World Radiocommunication Conference 2019(WRC-19),countries have s

26、tarted to assign spectrum within the bands identified for IMT globally 24.2527.5 GHz and 3743.5 GHz.Allocations in the 28 GHz band for mobile usage have also been happening across the globe.The 28 and 38 GHz bands have been allocated in the US,whole or parts of 26 GHz in European countries,and 26 or

27、 28 GHz in countries in Asia Pacific,and Central and Latin America.The decisions to license for 5G NR are taken individually,country by country,and many more countries are already in the process of assigning these bands for 5G NR.The 42 GHz band (40.543.5 GHz)is currently being harmonized for MFCN(M

28、obile/Fixed Communication Networks)in Europe,allowing 5G NR deployments,but the transition of the 42 GHz frequency band to 5G NR use in Europe is unlikely to happen before 2025.For WRC-23,the upper 6 GHz band is up for consideration for IMT identification.Globally installed baseThere are 10 million

29、transceivers in global use.10mE-band transceivers account for 6 percent of the global installed base.6%North America6781011131518232628323842 70/80 GHzMicrowave backhaul useUnder transition to 5G NR5G NRUnder consideration for 5G NRTransferred to 5G NR for new deploymentsLatin AmericaSub-Saharan Afr

30、icaMediterraneanWestern and Central EuropeNorthern Europe and Central AsiaMiddle EastIndiaSouth East Asia and OceaniaNorth East Asia5Ericsson Microwave Outlook|October 2022Some countries have allocated 5,9256,425 MHz(lower 6 GHz)for licensed exempt use,e.g.Wi-Fi,NR-U (NR in unlicensed spectrum),and

31、very few have expanded this allocation up to 7,125 MHz,like the US.The FCC has tried to introduce regulations to allow co-existence with fixed-service transport.However,we are still in the early days of understanding the real impact on fixed service.It remains to be seen what impacts license exempti

32、on will have on 6 GHz fixed service over time and if issues arise,how they will be solved as unlicensed spectrum is not controlled.Deployment of unlicensed services in fixed service bands,which are designed for interference-free environment and are sensitive due to its short traffic burst,should be

33、avoided.Sharing with another licensed service,such as 5G NR,is more feasible,requiring coordination where needed at a national level.Focusing on new deployments in the different frequency ranges,Figure 4 shows actual and predicted shares from 2015 to 2027.The following high-level trends can be seen:

34、E-bandThe most significant change in the microwave spectrum the last 1015 years has been the introduction of the E-band(70/80 GHz).This is a band that allows very wide channels and multi-Gbps capacity in a single radio,enabling 5G NR capacities in microwave backhaul.Five years ago,the E-band was alr

35、eady well established in multiple markets.However,the E-band share of the global market was still low and the number of markets deploying E-band in high volumes were limited.Based on the assumption that India,the worlds largest microwave market,would soon open up the E-band,we predicted in 2017 that

36、 the deployment share of E-band would be 20 percent by 2025.Today,we are slightly behind that prediction by one or two years due to delays in E-band introduction in India.But now,the Indian 5G NR spectrum auction has taken place,and authorities acknowledge that sufficient backhaul spectrum is needed

37、 to enable the 5G NR roll-out and they are therefore also allotting E-band carriers to service providers.With this significant movement in India,as well as uptake in multiple other countries around the globe,we therefore estimate that the previous prediction of a global new deployment share of 20 pe

38、rcent by 2025 is still within reach and that it will continue to grow to 25 percent by 2027.This 25 percent will be a combination of links using E-band as standalone and E-band in multi-band configurations.V-bandA band that was predicted to grow was the V-band(60 GHz),especially in small cell backha

39、ul applications.The predictions were quite modest but did not materialize due to small cells not taking off,a scattered spectrum availability,and the preference for licensed spectrum for backhaul applications.The V-band will now instead be used by unlicensed services,both indoor and outdoor,as short

40、-range devices with WiGig technology.Figure 4:New deployment share per frequency range78%In 2027 E-band(70/80 GHz)will account for 25 percent of new deployments,both as SA and in multi-band solutions.25%New deployments per frequency rangeTraditional bandsWithin the traditional bands(642 GHz),there h

41、as been some movement between bands.6 GHz is still going strong in the low end of the spectrum,but some shift of volumes towards 7 and 8 GHz is expected when unlicensed services(such as Wi-Fi or NR-U)start densifying.Countries with rural usage of 6 GHz are expected to coordinate with licensed 5G NR.

42、At the high end of the spectrum there is some movement away from bands that have been allocated to 5G NR,like 26,28,38 and 42 GHz in favor of the 32 GHz band.Going forward,this will depend greatly upon 5G NR high-band uptake and availability of other bands,such as 32 GHz.This is market specific,and

43、each country has its own prerequisites.For example,the 26 and 38 GHz bands are well-established high-volume bands in Europe and the Middle East,so in those markets it will be a very long-term transition from fixed services usage to 5G NR.W-and D-bandThe frequency bands between 92175 GHz(W-and D-band

44、)offer 5 times as much spectrum as the E-band.This makes them key spectrum resources for the evolution of 5G NR and 6G wireless backhaul,but they are also in consideration for future 6G access,a solution that accommodates the needs of both services and ensures an equally powerful access and backhaul

45、 development is to be considered.The W-band alone (92114 GHz)offers close to twice the amount of spectrum available in the E-band.In late 2020,in one of the first field trials with pre-commercial W-band radios,it was shown that the W-band will offer similar performance to the E-band in terms of both

46、 hop length,availability and transport capacity.To benefit from the existing ecosystem,W-band radios 613 GHz1523 GHzW-bandD-band2642 GHz60 GHz70/80 GHz100%80%60%40%20%0%20152027202520232021201920176Ericsson Microwave Outlook|October 2022will support similar channel bandwidths,modulations,antennas,an

47、d output powers as the E-band.The radio chain in both E-and W-band radios will be based on gallium-arsenide(GaAs)technology,a proven and well-known technology for wireless backhaul radios.However,in the short term it is not expected that GaAs will cover the full D-band(130174.5 GHz)with sufficient p

48、erformance.D-band radios will therefore be based on silicon-germanium(SiGe)technology.As a consequence,D-band radios will not be able to reach similar system gains to E-and W-band radios.Nevertheless,broad channel bandwidths and a high carrier frequency enable radios with high-gain antennas and a sm

49、all form factor which will be of importance for connecting future small cell radio networks in urban environments.The traditional bands(642 GHz)remain the backbone for wireless backhaul.The E-band(70/80 GHz)has made a remarkable journey and can now be considered to have entered the maturity stage,(s

50、ee Figure 5).This does not mean that no further advancements will be made.It is rather that it is now a stable,high-volume mass market,with product refinements and a good component ecosystem.There have been first-generation products on the market for a long time for the V-band(60 GHz),but the market

51、 and volumes have never taken off.The V-band has been caught in the classic product introduction chasm,as previously described,and is not expected to continue the journey up the maturity curve(for fixed services).Over the last five years we have seen a rapid maturation beyond 100 GHz radio technolog

52、y,and today there is standardization,plans and pre-commercial point-to-point radios available for trials in the W-band.Both W-band and D-band are untapped high-capacity spectrum resources that today have interests from multiple industries.Therefore a solution that accommodates the needs of both 6G a

53、ccess and fixed service backhaul needs is required.Commercial volumes in these bands are not expected until around 2025 and beyond depending on spectrum band.Maturity of the different bandsFigure 5:Time and steps to reach maturity in a new frequency bandPosition of band 2017Position of band 2022D-ba

54、ndW-band6-42GHzV-band failed to cross the product introduction chasmHigh/stable volumesMass marketProduct iterationsBand opened globallyVolumes increasing fastResearch Prototypes Standarization beginsFirst productsFew countriesLow volumesProduct iterations More countriesVolumes increasingTimeChasmMa

55、turityV-bandW-bandD-bandE-bandE-band6-42GHzV-bandMajor technology steps take around 10 years from start to early maturity.10 years 7Ericsson Microwave Outlook|October 2022More aggressive frequency reuse is a way to achieve higher link capacity in networks without the need for more spectrum.However,a

56、re there other benefits of higher frequency reuse?What about interference between closely spaced links and how does it affect availability?To shed some light on these questions,this article describes and compares the concepts of frequency Reuse 1 and Reuse 2.Frequency reuseTodays networks most often

57、 employ traditional planning strategies where neighboring links are,together with high-performance antennas,allocated separate frequency channels to guarantee principally interference-free operation.As capacity demand increases in our networks,the need for wider channels also increases.However,spect

58、rum is typically limited,and it is therefore challenging to achieve wider channels without reducing the number of separate Maximizing capacity in spectrum-limited networksCan higher frequency reuse provide a viable solution to meet increasing demand for more capacity in microwave networks with limit

59、ed spectrum?channels.The fewer channels there are available in a network,the greater the risk of interference.One extreme deployment scenario is a frequency Reuse 1 network.This denotes a network where each link is allocated the same frequency channel,and the total available bandwidth is,thus,used b

60、y all links.Another deployment scenario is a Reuse 2 network where the total bandwidth is split into two halves with each half comprising a separate frequency channel.In Reuse 2,neighboring links are allocated different frequency channels.On one hand,the risk of interference between neighboring link

61、s is much higher in a Reuse 1 network when compared to a Reuse 2 network,but,on the other hand,the channel bandwidth allocated to each link is doubled.Therefore,the trade-off between interference and bandwidth becomes of high interest.Traditionally,backhaul links operate in the bandwidth-limited reg

62、ime where the signal-to-interference-and-noise ratio(SINR)is very high.However,in the bandwidth-limited regime,the link capacity scales linearly with bandwidth and only logarithmically with SINR.Interference will reduce SINR,but the key point is that it is much more beneficial to take a slight penal

63、ty in SINR in order to be able to enjoy a wider bandwidth when the system is bandwidth-limited.Loss in SINR translates directly to loss in availability,so a very relevant question is what availability we should expect in a Reuse 1 network where links may interfere with each other.To make things slig

64、htly more complicated(or,perhaps,more interesting),modern systems may also use traffic-aware output power control,which means that the output power of an interfering link depends on the instantaneous traffic passing through that link.Furthermore,when links increase their output powers to meet certai

65、n SINR or capacity demands,this may lead to links rushing their output powers when competing for capacity if not carefully controlled.Figure 6:Higher frequency reuse with wider bandwidthangleReuse 2Reuse 156 MHz112 MHzUsing two different 56 MHz channels,in two neighboring hops with a small angle bet

66、ween them.Using one and the same 112 MHz channel in neighboring hops,with a small angle between them.This provides twice the bandwidth with the downside of increased risk of interference.56 MHz112 MHz8Ericsson Microwave Outlook|October 2022Figure 6 illustrates a simple Reuse 2 versus a Reuse 1 syste

67、m,consisting of two links where the total bandwidth in both systems is 112 MHz.In Reuse 2,the total bandwidth is split into two 56 MHz channels,and each link is allocated a separate 56 MHz channel which assumes interference-free operation between the links.While in the Reuse 1 system,both links use

68、the same 112 MHz channel to enjoy the full bandwidth but with increased risk of interference between the links.The potential peak capacity of the Reuse 1 system is thus twice the peak capacity of the Reuse 2 system.Achievable capacityFigure 7 shows the achievable capacity rate regions for the simple

69、 two-link system illustrated in Figure 6.The simulation parameters can be seen in the box underneath the figure.The x-axis represents the capacity of one of the links in Figure 6 and the y-axis represents the capacity of the other link.Any rate combination point in the graph represents the capacity

70、rates that the two links can achieve at the same time.The capacity is achieved by using the minimum output power,in other words traffic-aware output power,that fulfills the corresponding capacity with at least 99.995 percent availability.The different rate regions are colored differently,with orange

71、 representing the unachievable rate region.“Unachievable”means that both links cannot achieve any of the rate combinations within that region at the same time.The dark blue region is the achievable rate region for a Reuse 1 system which has 36 dB of antenna discrimination or isolation between the tw

72、o links.The antenna discrimination is dictated by the angular separation between the links and the antennas used.Finally,the light blue region is the achievable rate region for a Reuse 1 system with 28 dB of antenna discrimination,and the green region is the achievable rate region for a Reuse 2 syst

73、em.By observing the rate regions in Figure 7,we can make some interesting observations:The peak capacity of the Reuse 1 system is twice the peak capacity of the Reuse 2 system.The capacity region of the Reuse 2 system is square since there is no interference between the links.When the antenna discri

74、mination is not large enough,it is sometimes not possible to achieve peak capacity for both links at the same time in a Reuse 1 system,due to too much interference.The higher the antenna discrimination,the higher the rates that can be achieved simultaneously for both links in a Reuse 1 system.Antenn

75、a discriminationAs mentioned above,antenna discrimination between neighboring links affects achievable rates because of its ability to suppress interference.Antenna discrimination can be improved by using larger antennas,by using larger separation angles between antennas,or a combination of both.Lar

76、ger antennas provide more antenna discrimination thanks to narrower beamwidths.Figure 8 shows the possible Simulation parameters Rain zone Gothenburg,Sweden 43 mm/h(99.995%)Carrier:15 GHz Max power:18 dBm Bandwidth:112 MHzAntenna:ETSI class 3,0.9 m(Figures 7 and 8),0.3 m(Figure 8).Min power:-10 dBm

77、Hop length:4 km(only applies to Figure 7)Figure 7:Capacity rates available with two close linksFigure 8:Hop distances with different anglesThe peak capacity of the Reuse 1 system is twice the peak capacity of the Reuse 2 system.2x1000912345678000200Reuse 1 with 28 dB discriminationThe figure shows w

78、hich rate combinations are possible with at least 99.995%availability for two links,using either Reuse 1 or Reuse 2.As the antenna discrimination increases for Reuse 1,the available rate region increases.With increased antenna discrimination the two links cause less interference to each other.The fi

79、gure shows the possible hop distance for Reuse 1 and Reuse 2 with an availability of 99.995%at 550 Mbps.If the antenna discrimination reaches above 23.5 dB,the hop length almost doubles for Reuse 1 compared to Reuse 2.Reuse 1 with 0.9 m antennaReuse 2 with 0.9 m antennaReuse 1 with 0.3 m antennaReus

80、e 2 with 0.3 m antennaCapacity(Mbps)Distance(km)Capacity(Mbps)Angle(degrees)Reuse 1 with 36 dB discriminationReuse 2 Unachievable2004004006006008008001000141210864209Ericsson Microwave Outlook|October 2022Figure 9:The impact of antenna discrimination on available capacitySimulation parameters Rain z

81、one Gothenburg,Sweden 43 mm/h(99.995%)Carrier:15 GHzAntenna:ETSI class 3,0.9 mMax power:18 dBmMin power:-10 dBmBandwidth:112 MHzHop length:9.5 kmhop distances with an availability target of 99.995 percent at 550 Mbps.If the antenna discrimination reaches above 23.5 dB,the hop length approximately do

82、ubles for Reuse 1 compared to its Reuse 2 counterpart.The isolation value of 23.5 dB occurs approximately at 5 degrees of angular separation for 0.9 m antennas and 10 degrees for 0.3 m antennas,which in this case should be regarded as the minimum angular separations for conventional ETSI class 3 ant

83、ennas.Angular separation clearly plays a very important role in Reuse 1 systems.To further explore the importance of antenna discrimination,we have plotted capacity at two different availabilities against antenna discrimination in Figure 9,for a link with random interference from a neighboring link

84、that transports random traffic.Additional simulation parameters are shown in the box underneath the figure.If the antenna discrimination,or similarly,the angular separation between antennas is too small,then there is not enough interference suppression for Reuse 1 to work properly.However,if the ant

85、enna discrimination is 23.5 dB or above,then the Reuse 1 system will outperform the Reuse 2 system.Maximum capacity for Reuse 1 is achieved at 41.5 dB of antenna discrimination,which in the simulated case corresponds to 4096 Quadrature Amplitude Modulation(QAM).Another peak rate would require anothe

86、r antenna discrimination.For the simulated case however,the corresponding angular separations are highlighted in the boxes to the right of the figure.Note that Reuse 1 can already outperform Reuse 2 at relatively small angular separations,and that its peak capacity is twice that of Reuse 2.Conclusio

87、nReuse 1 offers several benefits over Reuse 2.Foremost,it offers wider channels and more efficient spectrum usage when the same frequency channel is used across the whole network.Wider channels translate to higher capacity for a given availability target or longer hop lengths for a given availabilit

88、y and capacity target.It should be stressed that it is important to fulfill the minimum requirement on antenna discrimination,since this provides the required interference suppression which enables the use of Reuse 1.The good news is that the required antenna discrimination already occurs at relativ

89、ely small angular separations,for example 5 to 10 degrees,for commercially used ETSI class 3 antennas.Of course,larger antenna discrimination results in larger benefits.Depending on antenna size,peak capacity is achieved at 30 to 50 degrees of antenna separation.These examples are for 15 GHz links w

90、ith 2x56 MHz(Reuse 2)or 1x112 MHz(Reuse 1),evaluated with respect to antenna discrimination which depends on frequency and antenna size.However,Reuse 1 is generic;it can be used in any frequency band,with any channel size in block-licensed spectrum.For example,2x28 MHz may be interesting to replace

91、with 1x56 MHz in some countries.In fact,it was recently announced that India will allocate two 250 MHz channels in E-band for 5G transport.Reuse 1 has big potential in E-band as very narrow beamwidths are typically used,limiting co-channel interference.To conclude,Reuse 1 will play an important role

92、 in meeting increasing capacity demands in dense networks with limited spectrum where there is a considerable need for aggressive channel reuse.Maximum capacity for Reuse 1 is achieved at 41.5 dB and aboveAntenna discrimination(dB)02004006008001,0001,20050403020100At only a 10 angle between 2 links,

93、Reuse 1 delivers higher capacity than Reuse 2 with 0.3 m antennas.Reuse 1 delivers higher capacity than Reuse 2 at 23.5 dB and aboveETSI class 3 antenna0.3 m0.6 m0.9 mAngle between links504830ETSI class 3 antenna0.3 m0.6 m0.9 mAngle between links1075Capacity(Mbps)Reuse 1 with 99.5%availability Reuse

94、 2 with 99.5%availability Reuse 1 with 99.95%availability Reuse 2 with 99.95%availability10Ericsson Microwave Outlook|October 2022Energy per transported bit has steadily decreased during the last two decades.Both existing and new energy efficiency functions,together with the introduction of AI,provi

95、des new and efficient tools to continue this evolution.Increasing energy efficiency in microwave networksThe energy efficiency of microwave networks,measured as power consumption How to reduce power consumption in microwave networksEnergy efficiency in mobile networks is key to reducing operational

96、costs and reaching net zero sustainability goals.over transmitted capacity(W/Mbps),has improved significantly over time.This has largely been due to increased modulation schemes,wider frequency channels,and the introduction of carrier aggregation leading to higher transmitted capacity per single rad

97、io.In this way,new microwave equipment has been able to support the transitions from 3G to 4G and to 5G mobile telecom standards.Over the last two decades,Figure 10:Power consumption evolution of 15 and 70/80 GHz nodesthe energy efficiency of microwave radios in traditional bands(642 GHz),has improv

98、ed by a factor of 10(Figure 10).The introduction of 70/80 GHz E-band radios and up to 2 GHz channels accelerated this evolution with up to a factor of 5.This has resulted in an energy efficiency increase of more than a factor of 50 over the last 2 decades.Reducing power consumption through traffic-a

99、ware power functionalityThe traffic in mobile networks varies over time and peak rates are,in practice,often only reached during shorter time periods and not during the full 24-hour day.A microwave link could thus be fully utilized during busy hours while being almost unused during low traffic perio

100、ds.By being aware of traffic demands,the radio unit can reduce power consumption by dynamically adjusting the modulation scheme and output power to meet current capacity needs.This can momentarily reduce power consumption up to 30 percent.For a complete wireless backhaul system including modem,power

101、 supply and traffic processing units this would correspond to energy savings of approximately 10 percent.Figure 11 shows an example of how the power consumption of a radio unit could vary over time when adapting the link capacity to traffic demand.2020The energy efficiency of microwave radios has in

102、creased by a factor of 50 over the last 2 decades.50 xOver 2 decades,the power efficiency of a microwave link in a traditional band,like 15 GHz,has increased 10 times.Including E-band,the increase is 50-fold.The main reason for this growth is the usage of higher modulation schemes and wider frequenc

103、y channels in the radio.0%20021x56 MHz 16 QAM1x56 MHz 256 QAM1x56 MHz 1024 QAM1x56 MHz 4096 QAM2x112 MHz 1024 QAM1x1000 MHz QPSK1x250 MHz 64 QAM1x2000 MHz 128 QAM2004200620082010201220142016201825%50%75%Power consumption/capacity(W/Mbps normalized)Year100%11Ericsson Microwave Outlook|October 2022Usi

104、ng deep sleep to save power in multi-carrier linksTo cope with increasing traffic in mobile networks,more and more microwave radio links evolve from single carrier 1+0 configurations into bonded systems of 2+0 and 4+0 links.However,as before,the extra capacity will frequently not be needed during th

105、e full 24-hour cycle.Energy can be saved by placing unused carriers into deep sleep mode during low-traffic hours.With AI and machine learning techniques,the microwave nodes can learn the traffic patterns of each link and optimize the deep sleep periods to match the unique traffic patterns of the si

106、te.This makes sure that unused carriers are placed in deep sleep when not needed,but only when there is a negligible risk of causing congestion events.Introducing AI to take the next step in power savingFigure 12 shows an example of supported capacity(blue and purple)in a 2+0 link configuration with

107、 traffic patterns(green)over a week.In between the busy hours there are“windows”where the capacity of only one radio link is enough to fulfill the traffic demand.The second radio link can be placed in deep sleep in these periods,thereby saving energy.TimeFigure 11:Traffic-aware output power function

108、Figure 12:Radio deep sleep in dual-carrier backhaul linksFixed-hour deep sleep Putting the radio in and out of deep sleep based on set patterns for low-traffic hours of the day,such as 8 hours during night time.AI powered deep sleep Uses AI to learn unique network utilization patterns at individual

109、sites and put the radio in and out of deep sleep based on forecasted traffic load.Capacity(Mbps)WednesdayThursdayFridayTimeSaturday1x radio in deep sleep1 x Radio (1+0)2 x Radio (2+0 XPIC)SundayMondayCapacity available with fixed-hour deep sleepCapacity available with AI-powered deep sleepCapacity n

110、eeded8006004002001003005007000Save up to 30 percent power consumption per radio.Capacity(Mbps)TimePercentage of full radio power consumption(%)800Fixed power(%)Traffic-aware output power(%)80%90%100%70070%60060%50050%40040%30030%20020%10010%00%Increased capacity equal to increase of modulation,outpu

111、t power and power consumption.Decrease of capacity equal to lower order modulation,reduced output power and power consumption.TX powerTX powerCapacityAvailable capacity(Mbps)Capacity needed(Mbps)Capacity12Ericsson Microwave Outlook|October 2022But how do we decide the optimum deep sleep time periods

112、 in a way that is as easy,manageable,and non-intrusive as possible?Manually optimizing the sleep period for each link in a medium-to-large backhaul network(5000 links)is not feasible in practice.The figure shows utilization of a second carrier in a dual-carrier system,calculated over five years base

113、d on the traffic model of a real mobile network.Figure 13:Utilization of a second carrier in a dual-carrier system over five yearsHowever,as a starting point,one could specify fixed-time windows for the entire network or parts of the network.In Figure 12 we use a fixed-time window of 8-hour deep sle

114、ep during night-time(purple).When comparing this scheme with the AI-optimized time window(blue),we can see that the AI-powered scheme is able to put the microwave link into deep sleep for longer periods than the fixed 8-hour time window.Fixed-time windows could be the starting point for introducing

115、deep sleep functionality in microwave networks and AI technology would be the natural evolution to optimize this.Energy efficiency gains in live backhaul networksTo understand the real potential of traffic-aware output power and deep sleep functionality we studied a live backhaul network operated by

116、 a major European service provider in 2022.The network was recently upgraded from a 1+0 to an XPIC 2+0(bonded dual carrier using cross-polar interference cancellation)configuration to support the expected traffic growth with the introduction of 5G.By measuring the utilization of each link,we calcula

117、ted the time the second carrier was needed.This was defined as the time the utilization of the full 2+0 link was higher than 40 percent.The result is shown in Figure 13.As network traffic grows over time,we can see that the second carrier is used more and more often.In Figure 13 we used the Ericsson

118、 Mobility Report 2022 forecast for year-on-year(YoY)network traffic growth of 27 percent.As shown,the network is well prepared to handle the traffic growth in the coming five years.Suburban hub-site with dual carriersUtilization of a second carrierYear 1Year 2Year 3Year 4Year 580%90%100%70%60%50%40%

119、30%20%10%0%0%10%30%20%40%50%80%70%100%60%90%Percentage of microwave backhaul network13Ericsson Microwave Outlook|October 2022congestion,but as shown we still outperform the deep sleep case with 8-hour fixed time slots even as traffic increases yearly.In year 5,we still see a 15 percent reduction in

120、energy consumption compared to the case without traffic-aware power functionality.To estimate the energy savings for a medium-sized network with similar traffic patterns,we extrapolated the energy savings in our case study to a network with 5,000 2+0 links.The accumulated energy saving over 5 years

121、would be 3 GWh for the traffic-aware output power save case,6 GWh for fixed 8-hour deep sleep case and 10 GWh for AI-powered deep sleep comparable to a 20 percent reduction in network energy consumption over 5 years.In the first and third cases these savings would be achieved without any impact on t

122、he network performance or user experience.SummaryThe energy per transported bit for traditional wireless backhaul has been reduced by a factor of 10 over the last two decades.The introduction of E-band in 2015 added another factor of 5 resulting in an improvement in energy efficiency of more than 50

123、 times when comparing traditional frequency bands in the beginning of the century with high-performance E-band links in the 2020s.With the introduction of traffic-aware power functionality,for example microwave networks that adapt energy consumption to meet the momentary traffic demand,we can push t

124、he energy efficiency curve even further.In a case study together with a service provider,with a medium-sized microwave network,the combination of traffic-aware output power and AI-powered deep sleep functionality for multi-carrier links resulted in an energy saving of 20 percent over five years,with

125、 negligible impact on user experience or service availability.Up to 20 percent of network energy can be saved over 5 years in our studied network with AI-powered deep-sleep and traffic-aware output power.20%In year 1 around 10 percent of the 2+0 links use the second carrier more than 20 percent of t

126、he time.In year 3,approximately 25 percent of the links use the second carrier over 20 percent of the time and in year 5 almost 80 percent of the links use the second carrier for 20 percent of the time.In Figure 14 we calculated the expected energy saving for three different use cases:(I)traffic-awa

127、re output power;(II)fixed 8-hour deep sleep combined with traffic-aware output power;and(III)AI-powered deep sleep combined with traffic-aware output power.In the first case,energy saving from traffic-aware output power save is relatively constant,remaining at around 6 percent even as traffic grows

128、over time.In the second case traffic-aware output power is combined with fixed 8-hour deep sleep,so that the second carrier is put into deep sleep during night hours,for an 8-hour period.Here,the energy saving was around 12 percent.In fixed-hour deep sleep we have accepted that we may congest the li

129、nk at night,and therefore energy saving is constant as traffic grows,but in fact the congestion events will be frequent.In the third case,AI is used to learn the traffic patterns at each unique site,and continuously optimize the deep sleep schemes.We will thereby avoid Figure 14:Energy savings over

130、five yearsEnergy saving for full networkAccumulated energy saving assuming 5,000 links (GWh)Year25%12 20%1015%810%65%420%013245Energy savings for networkAccumulated energy savingFixed-hour deep sleep with traffic-aware output powerAI-powered deep sleep with traffic-aware output powerTraffic-aware ou

131、tput powerTraffic-aware output powerFixed-hour deep sleep with traffic-aware output powerAI-powered deep sleep with traffic-aware output power14Ericsson Microwave Outlook|October 2022Distances between 2060 km make multi-channel systems very appealing.Long haul technology is a relevant solution,espec

132、ially since it offers handling of multi-channels while minimizing the number and the size of antennas needed.This is significant for total cost of ownership(TCO),both for initial investment and for power consumption.In addition,it is important to consider spectrum availability in lower frequencies w

133、here wider channels are often not yet allowed.Reaching 5 Gbps using 40 MHz channels requires at least 14 traffic channels,and utilization of 28 MHz channels requires 18 traffic channels.Such big systems have a large footprint,with waveguides and dehydrators.Reducing the footprint and achieving a mor

134、e compact and cost-efficient system extends the usage to more locations than currently for long haul systems.So,whats the solution?The rural challenge for 5G backhaulAt distances of 2060 km it starts to become a challenge to reach 510 Gbps using just 12 wide channels.The first and most obvious solut

135、ion is to use wider channels if possible.Moving to 80 MHz channels means an 8-channel system can reach up to 6.4 Gbps and a 56 MHz system with 12 channels reaches 6.6 Gbps capacity.But if wider channels are not allowed,how can the hardware needed be reduced?Not all rural systems need to perform over

136、 distances of 75150 km,so it is also possible to use less than maximum output power(Pout)with good results in many cases.This enables use of carrier aggregation in long haul systems.When carrier aggregation is used,the same output power needs to be distributed over two channels and since the total b

137、andwidth is wider than one channel the maximum Pout needs to be reduced a little.In shorthaul,this technology is starting to be used in many places with good results.Adding it to the long haul toolbox will further increase flexibility,enabling users to benefit from greater channel capacity while usi

138、ng half the number of radios and filters.Lets examine what it looks like when building a 20 km long hop without space diversity in 11 GHz using 40 MHz channels and a 0.9 m antenna.A traditional 8+0 without carrier aggregation and full Pout available per channel provides a maximum of 3 Gbps with a gu

139、aranteed capacity of 1.7 Gbps.Carrier aggregation makes it possible to instead use a 16+0 system,which still has 8 filters and radios and can reach 5.7 Gbps at peak rate with a guaranteed capacity of 2.3 Gbps.If using carrier aggregation the total power consumption for the 16+0 system is closer to a

140、 traditional 8+0 system as fewer transmitters are used.This also impacts the footprint and the initial hardware investment,greatly benefiting TCO.Figure 15:Utilizing carrier aggregation in a long haul system with channel filtersFigure 16:Carrier aggregation impact on power consumption and hardware(H

141、W)footprintfc filter center frequencyf1&f2 center frequency for channel 1 and channel 2With carrier aggregation two carriers are used inside one channel filter since only one radio handles both carriers.VH Number of HW radio transmitters with no carrier aggregationNumber of HW radio transmitters whe

142、n using carrier aggregation65432100168412218106142+014+016+012+010+08+06+04+0Relative power consumption without carrier aggregationRelative power consumption when using carrier aggregationRelatiove power consumptionNumber of HW radio channels usedf1f2fc15Ericsson Microwave Outlook|October 2022In sum

143、mary,using carrier aggregation makes it possible to increase the peak capacity by 67 percent with the same availability while reducing hardware footprint,power usage and TCO compared to expansion using traditional solutions.Can MIMO come to the rescue?Line-of-sight multiple-input multiple-output(MIM

144、O)as used in microwave is often seen as a solution when spectrum is scarce,as it has the potential to double available spectrum capacity.However,this technology is still seldom used in long haul because optimal antenna separation becomes increasingly problematic with hop distance and lower frequenci

145、es.When using less than optimal separation,the traffic channel will be at greater risk of fading due to phase variation of the signal,which can negatively impact capacity.To avoid this impacting all channels simultaniously,a link can be created,combining some channels using space diversity(SD)with s

146、ome channels using MIMO in a multi-channel system.Combining these channels using radio-link bonding produces a similar solution as multi-band,with a combination of capacities with different availabilities,which are all error-free.This ensures guaranteed traffic can have the availability of a traditi

147、onal SD link,and peak capacity can be increased by up to 50 percent,or even by up to 75 percent,compared to a traditional SD hop using the same spectrum.The example in Figure 18 shows four radio frequencies in two polarizations and two antennas.A traditional 8+0 SD system achieves 1.2 Gbps at 59 s a

148、nd 2.8 Gbps at 39 s availability.If instead half the channels are used as 4x4 MIMO and the rest as 4+0 SD with radio link bonding,it provides 1.4 Gbps at 59 s and 3.2 Gbps at 49 s availability,plus an astounding 4.4 Gbps for 99.8 percent of the year.However,this requires space for near optimal anten

149、na separation in the tower,and that is normally a limiting factor.If it is possible to achieve,peak link capacity can be increased by 50 percent while keeping a reasonably high capacity with 59 s availability.If one can accept only 2+0 SD and make the rest into 3x(4x4)MIMO,even more peak capacity ca

150、n be reached.The challenge of getting enough transport capacity to rural 5G sites can be overcome,but it may be at the expense of some long-standing practices.We have seen in previous Microwave Outlook articles that end-user satisfaction in a 5G mobile network is linked more to peak capacity support

151、 than to the 59 s availability.Utilizing carrier aggregation and line-of-sight MIMO could be an efficient way to meet those expectations.Figure 17:Available capacity with and without carrier aggregationFigure 18:Available capacity in a combined space diversity(SD)and MIMO hopCalculations based on us

152、ing 11 GHz,40 MHz channels,0.9 m antennas,and a 20 km long hop in Sweden.Calculations based on using 11 GHz,40 MHz channels,with 20 m antenna separation,1.8 m antennas,and a 30 km long hop in Sweden.Capacity availability8+0 no carrier aggregation16+0 using carrier aggregationCapacity increase with c

153、arrier aggregation%99.995%2.0 Gbps2.9 Gbps+45%99.99%2.2 Gbps3.4 Gbps+54%99.9%2.7 Gbps4.5 Gbps+67%Capacity in MbpsAvailability8+0 SD4+0 SD2x(4x4)MIMOCombined capacity with 4+0 SD and 2x(4x4)MIMOCapacity gain with 4+0 SD and 2x(4x4)MIMOCombined capacity with 2+0 SD and 3x(4x4)MIMOCapacity gain with 2+

154、0 SD and 3(4x4)MIMO99.999%1168584800138418%149228%99.995%200010001728272836%309255%99.99%251212562000325630%362844%99.95%274413722608398045%459868%99.9%283214162744416047%482470%99.8%296014802960444050%518075%Add 50 percent capacity on a long haul hop by using carrier aggregation.50%The content of t

155、his document is subject to revision without notice due to continued progress in methodology,design and manufacturing.Ericsson shall have no liability for any error or damage of any kind resulting from the use of this documentEricssonSE-164 80 Stockholm,Sweden Telephone+46 10 719 0000 EAB-22:007365 U

156、en Ericsson 2022About EricssonEricsson enables communications service providers to capture the full value of connectivity.The companys portfolio spans Networks,Digital Services,Managed Services,and Emerging Business and is designed to help our customers go digital,increase efficiency and find new revenue streams.Ericssons investments in innovation have delivered the benefits of telephony and mobile broadband to billions of people around the world.The Ericsson stock is listed on Nasdaq Stockholm and on Nasdaq New Y