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Energy-Efcient Scheduling

and Bandwidth –EnergyEfciency Trade-O with lowLoad

Author:Ste an Videv and Harald Haas

The university o Edin urgh

Publish on: !EEE !"" #$%%

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!ntroduction• &ro'ose a (ethod or energy efcient resource

allocation and an algorith( or trading andwidthor energy efciency during low load 'eriods

• )se in LTE syste(s• Basic !dea* Score- ased scheduling• Score- ased 'rinci'le* to (a+e use o oth a

relative and a solute energy efciency (etric

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&revious ,or+s• %. trading transmission length or energy

efciency/• #. - 0oint efcient resource allocation

- &ower control that (ini(i1e inter erence and(a2i(i1e syste( ca'acity

• 3. Trade-of between *• Through'ut4 delay4 5etwor+ "a'acity4 Energy

efciency/• 6. Power-bandwidth trade-of in dense (ulti-

antenna relay networ+s/• 7. !nter erence avoidance• 8. slee' (ode• 9. "utting down on control signaling during low

tra c periods /

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Bandwidth Trade-o&rinci'le

General Scenario:%/ : user can expand his andwidth oot'rint y

using actor o ; loo+u' ta le2. hoose *

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Theoritical Treat(ent>%?6@The Potential energ! sa"ing gains:Based on Shannon "a'acity

" @ >%@B * "hannel BandwidthS * total received signal 'ower over the andwidth5 * 5oise 'ower! * !nter erence 'ower"* "a'acity

•

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Theoritical Treat(ent>#?6@#/ !n LTE syste(s4 andwidth is 'artitioned into =Bs/

"i * ca'acity o the =B with inde2 iBi * Bandwidth o a =B

Ti * Trans(ission &ower+C * 'ath gain etween t2 + and r2 C5o * 5oise 'ower density!i * inter erence 'ower received in =B i

D>#@

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Theoritical Treat(ent>3?6@• !deally4 the achieved S!5= at =Bi is greater than

S!5= target 4 i:

o reduce an this ine$ualit! to e$ualit! in order to ensurenerg! e cienc! and correct transmission.

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Theoritical Treat(ent>6?6@Scenario*%/ "alculate BE< S!5= target4Fro( the regular S!5=

Target i.• overall trans(ission rate a ter (ore =Bs are

allocated*

#/ :ssu(e :i > Ai G >N$ Bi Ii@ /Gkj) is a constant/

"alculate the (inu(u( trans(ission 'ower/

3/ "alculate ain in energy

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Theoritical ain or BE< Trans(ission

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Favora le "onditions• Find the eneIcial ti(e or a user to e2'and its andwidth*

•

BE< reJuires a scheduler4 e ore allowing or airness K control resourcedistri ution@/

Solution : %se energ! e cienc! score-based scheduling

n* total nu( er o =B 'er user in nor(al (ode

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Score- ased Scheduling• Score- ased scheduling 'rinci'le*

• )se an energy efciency (etric• Tailoring the allocation seJuence K con ict

regulation• :llocation using a score- ased scheduler4 relies

one*• "hannel gains• !nter erence characteristics• Energy (etric

• Goal * To Ind the (ost energy-efcient =Bs to trans(it

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Si(ulation• Si(ulation*

Syste( uses round ro in scheduling co('ared to #'ro'osed syste(s *

• EESBS >Energy Efciency Score Based Scheduling@• EESBS cou'le with BE

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Scenario >%?@

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Scenario >%?3@%/ Syste( * cellular#/ Me'loy(ent * a central cell with # tiered wra'-around/3/ Only central cell is considered/6/ "hannel (odel * LTE ur an (icro-cell >)(i@

d * distance etween trans(itter n receiver* "arrier reJuency >

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Scenario >#?3@N/ The 'ro a ility o line o sight >LOS@ is given y*

&r LOS G (in>%8 /d, %@>%− e2'> −d/ 37@@ e2'> −d/ 37@7/ Power control algorithm * Foschini-

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Scenario >3?3@9/ Each user is assu(ed to reJuire a set nu( er oreJuency resource loc+ in nor(al4 ench(ar+4(ode/%$/ The author would li+e to 'reserve the

trans(ission rate that was incident e ore theallocation o additional =Bs in BE

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"onclusion• The 'ro'osed scheduler and energy efcient

andwidth e2'ansion techniJue achievesigniIcant energy savings Q 93R

• On average4 a out 66R o the e2'ended energy issaved

• The techniJue 'ro(ises very signiIcant energy

savings when light overnight load actors are'resent/