Multimedia and Mobile Communication Laboratory. Outline Multimedia and Mobile Communication...

Multimedia and Mobile Communication Laboratory

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1. Introduction to CRN1. Introduction to CRN

Cognitive Radio NetworkDynamic spectrum accessOpportunistically utilize spectrum resourcesActive monitoring, tuning, working

Cognitive Radio NetworkDynamic spectrum accessOpportunistically utilize spectrum resourcesActive monitoring, tuning, working


Primary Users (PU), Secondary Users (SU)○ PU can start transmission anytime○ SU has to use bands occupied by no PU

Primary Users (PU), Secondary Users (SU)○ PU can start transmission anytime○ SU has to use bands occupied by no PU


Art of SU’s life in CRN : Jump and fill in the blanks! Art of SU’s life in CRN : Jump and fill in the blanks!

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2. Multi-radio Multi-path2. Multi-radio Multi-path


A

B CD E

Multiple Cognitive Radios1 for control signaling, M for data traffic

○ “Share” mode○ “Switch” mode

1 + N bands, N ≥ M

Multiple PathsSplit transmission mannerDuplicated transmission manner

Multiple Cognitive Radios1 for control signaling, M for data traffic

○ “Share” mode○ “Switch” mode

1 + N bands, N ≥ M

Multiple PathsSplit transmission mannerDuplicated transmission manner


Multi-path in Multi-radio Multi-hop CRN Multi-path in Multi-radio Multi-hop CRN


Spectrum PoolAll parameters of licensed/unlicensed bandsRadio and Band Usage Table (RBT)

B: Several available bands I: Number of flows that are using this band in this SUN: Number of flows that are using this band within 1- hop

neighborsR: Which radio is using this band in this SU“X” will be used to indicate PU occupation

Periodical exchange of hello message

Spectrum PoolAll parameters of licensed/unlicensed bandsRadio and Band Usage Table (RBT)

B: Several available bands I: Number of flows that are using this band in this SUN: Number of flows that are using this band within 1- hop

neighborsR: Which radio is using this band in this SU“X” will be used to indicate PU occupation

Periodical exchange of hello message


A Multi-radio Multi-hop CRN ExampleExisting SU flows:

Current PU traffics:○ P1 : b1○ P2 : b4○ P3 : b5

A Multi-radio Multi-hop CRN ExampleExisting SU flows:

Current PU traffics:○ P1 : b1○ P2 : b4○ P3 : b5


Route Discovery (DSR-like)Attach its own RBT into the RREQ

○ New RREQ_ID or old RREQ_ID but with hop count ≤ previous one rebroadcast (multipath)

Route Discovery (DSR-like)Attach its own RBT into the RREQ

○ New RREQ_ID or old RREQ_ID but with hop count ≤ previous one rebroadcast (multipath)

RREQ with RBTS

S

A B

D

FE

RREQ with RBTS RREQ with RBTS, E

RREQ with RBTS, A

RREQ with RBTS, E, F

RREQ with RBTS, A, B


RREQs arrives at DFirst RREQ

○ Primary Path (PP)Later RREQs

○ Candidate Path (CP) Radio & band selection

Preference: ○ Idle radio > “Share” > “Switch”

RBTs should be updated afterevery comparison!

RREQs arrives at DFirst RREQ

○ Primary Path (PP)Later RREQs

○ Candidate Path (CP) Radio & band selection

Preference: ○ Idle radio > “Share” > “Switch”

RBTs should be updated afterevery comparison!


○ RBTS & RBTA RBTS’ & RBTA’

○ RBTA’ & RBTB RBTA’’ & RBTB’

○ RBTB’ & RBTD RBTB’’ & RBTD’ …

○ …

○ RBTS & RBTA RBTS’ & RBTA’

○ RBTA’ & RBTB RBTA’’ & RBTB’

○ RBTB’ & RBTD RBTB’’ & RBTD’ …

○ …


Path Evaluation Metrics:Hop Count:

○ NPP: Hop count of PP

○ NCP: Hop count of CP

Band Overlapping Factor: FCP

α: weight factor○ balancing how we emphasize the jointness of

paths

Path Evaluation Metrics:Hop Count:

○ NPP: Hop count of PP

○ NCP: Hop count of CP

Band Overlapping Factor: FCP

α: weight factor○ balancing how we emphasize the jointness of

paths


Finally, two paths are established:○ Primary Path:

○ Secondary Path: ( selected from CPs)

Data Striping:○ Packets will be splitted and transmitted

throughput different paths simultaneously

Dual path: odd / even

Finally, two paths are established:○ Primary Path:

○ Secondary Path: ( selected from CPs)

Data Striping:○ Packets will be splitted and transmitted

throughput different paths simultaneously

Dual path: odd / even


Recovery: Recovery:


b1

S

F

P4

E

b4

Db3

b1

1

2 1 31

2

XStop transmitting to me, go other path!

Who is involved in this PU insertion?

New radio&band is assigned, let’s keep going

E3 ---- 3F2

b23

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3. Evaluation3. Evaluation

MPMR vs. MPSR(SMR) vs. SPMRNS2802.11a, 6Mbps, UDP7 orthogonal channels from 11a:

○ 36, 44, 52, 60, 149, 157, 1653 radios2 paths

MPMR vs. MPSR(SMR) vs. SPMRNS2802.11a, 6Mbps, UDP7 orthogonal channels from 11a:

○ 36, 44, 52, 60, 149, 157, 1653 radios2 paths


Maximum End-to-end Throughput:○ MPMR achieves much high end-to-end throughput○ MPSR uses single radio, low throughput○ SPMR uses one path, limited high throughput

Maximum End-to-end Throughput:○ MPMR achieves much high end-to-end throughput○ MPSR uses single radio, low throughput○ SPMR uses one path, limited high throughput

MPSR( )


Recovery Evaluation○ P4 begins at 3 sec.○ E detects the insertion○ is interrupted○ E and F re-select b2

○ ~120 ms

Recovery Evaluation○ P4 begins at 3 sec.○ E detects the insertion○ is interrupted○ E and F re-select b2

○ ~120 ms


E3 ---- 3F2

There is a degradation of throughput, for allMPSR achieves low throughput ( let’s ignore it…)SPMR transmission is terminatedMPMR keeps high speed transmission

There is a degradation of throughput, for allMPSR achieves low throughput ( let’s ignore it…)SPMR transmission is terminatedMPMR keeps high speed transmission

MPMR SPMR MPSR(SMR)


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4. Conclusion4. Conclusion

Multi-path Routing in Multi-radio Multi-hop Cognitive Radio NetworksRoute DiscoveryRadio/Band SelectionRoute Recovery

FinallyHigher route connectivityHigher end-to-end throughput

Multi-path Routing in Multi-radio Multi-hop Cognitive Radio NetworksRoute DiscoveryRadio/Band SelectionRoute Recovery

FinallyHigher route connectivityHigher end-to-end throughput


CurrentlyMassive simulationsDetailed evaluation

Future WorkMore efficient radio & band selection algorithmMore evaluation metrics of pathsFaster route recovery of SS’s trafficTry to cancel the extra radio for control signal

○ This is the most practical problem!

CurrentlyMassive simulationsDetailed evaluation

Future WorkMore efficient radio & band selection algorithmMore evaluation metrics of pathsFaster route recovery of SS’s trafficTry to cancel the extra radio for control signal

○ This is the most practical problem!


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