SlideShare uma empresa Scribd logo
1 de 19
Baixar para ler offline
Wireless Network Presentation

AutoMAC
(Rateless Wireless Concurrent Medium Access)
Aditya Gudipati, Stephanie Pereira, Sachin Katti

Standford University
Presented on :

Mobile Computing and Networking 2012 (MobiCom'12), August 22-26, 2012, Istanbul,Turkey.
Current Wireless Design
• Current Design : one Tx, one
frequency, one at time (uplink
and downlink)
>> Avoid the interference
• RTS/CTS/Backoff Mechanism
(protocols overhead)
>> Client need to sense the
carrier, to avoid collision

Limiting
network
throughput
Proposed Wireless Design
• Opposite approach : Exploit the
interference
• Multiple clients concurently Tx to
AP (uplink)
• AP concurently Tx to multiple
clients (downlink)
• Decode all constituent packets
from interference

Increasing
network
throughput
Exploiting Interference (Uplink)
y = h1x1+ h2x2 + N
AP

SIC
(Successive Interference
Cancelation)

h1x1
x1

y

A

x2
B

h2x2 + N
h2x2
Exploiting Interference (Uplink)
• No Interference Troughput

• Throughput for Client A

Rsic > Rnint
• Throughput for Client B

• Throughput system

gained extra
throughput,
without hurting
ongoing Tx
Exploiting Interference (Downlink)
(x1 + x2) /√2

SNR High

AP

(Stronger Node)

B

y = h1x1 /√2 + h2x2 /√2 + N

SIC
(Successive Interference
Cancelation)

SNR Low
(Weaker Node)

A

h1x1 /√2

y

y = h1x1 /√2 + h2x2 /√2 + N
h1x1 /√2

h2x2/√2+ N
h2x2/√2
Exploiting Interference (Downlink)
• number Tx required by stronger client < weaker
client to decode
• dividing Tx power, instead of increasing
• higher throughput when SNR different
• throughput at the equal SNR ∼ no interference
schemes
Exploiting Interference (Downlink)

Throughput A (Alice) and B (Bob) can be achieved by exploiting
interference compare to interference avoidance scheme
AutoMAC
• Sender didn't know actual SINR at receiver for
decoding ->Rateless Property
>> Rateless Codes (send rateless Tx, until
receiver can decode)
• Wastefull Tx because packet can be decoded less
than rateless encoding requirements
>> Speculative ACKing (number rateless Tx
depends on the SINR value)
AutoMAC : MAC Design
• Short Contention advertisement
• announce the number of users send
concurrently Tx in the next slot
• not sent, if AP want to transmit or concurrent
Tx in previous slot continue

• Frequency domain backoff technique
• client pickup random subcarrier
AutoMAC :
Exploit Uplink Interference
• Packet Encoding
• Orthogonal choice of rateless code (Strider or
Spinal codes)

• Decoding Constituent Packet with SIC
• Per-frame channel estimation
• Decoding Packet (Strider)
• Substracting Node'1 collission contribution
AutoMAC : Speculative ACKing
• Diferrent encoding time -> encoding order and
relative SNR between AP-Client
• Number of Tx is less for last decoded packet
than the first packet -> better SNR
• "Key" of ACKing technique :
• Estimate number of Tx for encoding packet ->
estimate effective SNR value
• SINR vs number Tx graph -> after M Tx, receiver
start ACK packet p
AutoMAC : Exploiting Broadcast on
Downlink
• same encoding technique for all client
– rateless encoding (strider's) -> rateless frame
– n frames add in complex domain -> one frame
– prepend header, pass frame to OFDM PHY for Tx

• decoding the own packet at last
– every client assumed best channel
– ensure SINR to decode and send the ACK -> AP
receive know the received signal strength
– apply the SIC in the order Tx from AP
Evaluation
outperform by 35% (include downlink)
decode packet in interference upto 3 packets
eleminates hidden terminal
multiplex upto 3 packets (downlink)
accurately estimates channel, frequency, and
sampling offsets
• 60% throughput gain over 802.11 MAC (uplink)
and 50% over an 802.11 style MAC
•
•
•
•
•
Evaluation

The Gains will increase as relative with SNR increase, and
AutoMAC gain 50 - 60 % over Conventional or Time Fair Wifi.
Evaluation

Time Spent and throughput fairness comparison
Gain Analysis
• Collision minimum, because no lack of
coordination and inability to decode ->
Centralized MAC
• Lower contention time -> frequency domain
backoff technique
• No overheads time for ACK waiting (SIFS,DIFS)
-> ACK one for every batch
• fraction time spent is higher 20% -> efficient
MAC protocol
Conslusion and References

Mais conteúdo relacionado

Mais procurados

Tcp Immediate Data Transfer
Tcp Immediate Data TransferTcp Immediate Data Transfer
Tcp Immediate Data TransferRam Dutt Shukla
 
Decentralized Predictive MAC Protocol for Ad Hoc Cognitive Radio Networks
Decentralized Predictive MAC Protocol for Ad Hoc Cognitive Radio NetworksDecentralized Predictive MAC Protocol for Ad Hoc Cognitive Radio Networks
Decentralized Predictive MAC Protocol for Ad Hoc Cognitive Radio NetworksIffat Anjum
 
An overview of TCP (Transmission Control Protocol)
An overview of TCP (Transmission Control Protocol)An overview of TCP (Transmission Control Protocol)
An overview of TCP (Transmission Control Protocol)Ammad Marwat
 
Core-Stateless Fair Queueing
Core-Stateless Fair QueueingCore-Stateless Fair Queueing
Core-Stateless Fair QueueingYuanxuan Wang
 
Mobile computing-tcp data flow control
Mobile computing-tcp data flow controlMobile computing-tcp data flow control
Mobile computing-tcp data flow controlSushant Kushwaha
 
Sliding window protocol
Sliding window protocolSliding window protocol
Sliding window protocolRishu Seth
 
Importance of sliding window protocol
Importance of sliding window protocolImportance of sliding window protocol
Importance of sliding window protocoleSAT Journals
 
Data link control
Data link controlData link control
Data link controlIffat Anjum
 
Datalink control(framing,protocols)
Datalink control(framing,protocols)Datalink control(framing,protocols)
Datalink control(framing,protocols)Hira Awan
 
Importance of sliding window protocol
Importance of sliding window protocolImportance of sliding window protocol
Importance of sliding window protocoleSAT Publishing House
 
Adoptive retransmission in TCP
Adoptive retransmission in TCPAdoptive retransmission in TCP
Adoptive retransmission in TCPselvakumar_b1985
 
Congestion Control in Computer Networks - ATM and TCP
Congestion Control in Computer Networks - ATM and TCPCongestion Control in Computer Networks - ATM and TCP
Congestion Control in Computer Networks - ATM and TCPAttila Balazs
 
Network time protocol
Network time protocolNetwork time protocol
Network time protocolMohd Amir
 

Mais procurados (20)

Tcp Immediate Data Transfer
Tcp Immediate Data TransferTcp Immediate Data Transfer
Tcp Immediate Data Transfer
 
Decentralized Predictive MAC Protocol for Ad Hoc Cognitive Radio Networks
Decentralized Predictive MAC Protocol for Ad Hoc Cognitive Radio NetworksDecentralized Predictive MAC Protocol for Ad Hoc Cognitive Radio Networks
Decentralized Predictive MAC Protocol for Ad Hoc Cognitive Radio Networks
 
An overview of TCP (Transmission Control Protocol)
An overview of TCP (Transmission Control Protocol)An overview of TCP (Transmission Control Protocol)
An overview of TCP (Transmission Control Protocol)
 
Core-Stateless Fair Queueing
Core-Stateless Fair QueueingCore-Stateless Fair Queueing
Core-Stateless Fair Queueing
 
Mobile computing-tcp data flow control
Mobile computing-tcp data flow controlMobile computing-tcp data flow control
Mobile computing-tcp data flow control
 
Tcp ip presentation
Tcp ip presentationTcp ip presentation
Tcp ip presentation
 
Go Back N Arq1
Go  Back N Arq1Go  Back N Arq1
Go Back N Arq1
 
Firewalls
FirewallsFirewalls
Firewalls
 
Sliding window protocol
Sliding window protocolSliding window protocol
Sliding window protocol
 
Importance of sliding window protocol
Importance of sliding window protocolImportance of sliding window protocol
Importance of sliding window protocol
 
T Tcp
T TcpT Tcp
T Tcp
 
Data link control
Data link controlData link control
Data link control
 
Datalink control(framing,protocols)
Datalink control(framing,protocols)Datalink control(framing,protocols)
Datalink control(framing,protocols)
 
Importance of sliding window protocol
Importance of sliding window protocolImportance of sliding window protocol
Importance of sliding window protocol
 
Adoptive retransmission in TCP
Adoptive retransmission in TCPAdoptive retransmission in TCP
Adoptive retransmission in TCP
 
Congestion Control in Computer Networks - ATM and TCP
Congestion Control in Computer Networks - ATM and TCPCongestion Control in Computer Networks - ATM and TCP
Congestion Control in Computer Networks - ATM and TCP
 
Transport Layer
Transport LayerTransport Layer
Transport Layer
 
Test
TestTest
Test
 
UCL
UCLUCL
UCL
 
Network time protocol
Network time protocolNetwork time protocol
Network time protocol
 

Destaque (17)

Network Virtualization - A Survey
Network Virtualization - A SurveyNetwork Virtualization - A Survey
Network Virtualization - A Survey
 
ETSI QoS Criteria and Measurements for Web Browsing (HTTP Service)
ETSI QoS Criteria and Measurements for Web Browsing (HTTP Service)ETSI QoS Criteria and Measurements for Web Browsing (HTTP Service)
ETSI QoS Criteria and Measurements for Web Browsing (HTTP Service)
 
Advanced networking - scheduling and QoS part 1
Advanced networking - scheduling and QoS part 1Advanced networking - scheduling and QoS part 1
Advanced networking - scheduling and QoS part 1
 
Feedback - By Paul Fellows
Feedback - By Paul FellowsFeedback - By Paul Fellows
Feedback - By Paul Fellows
 
Guia argentina de tratamiento de la EPOC
Guia argentina de tratamiento de la EPOCGuia argentina de tratamiento de la EPOC
Guia argentina de tratamiento de la EPOC
 
Performance mgmt 04.04.12
Performance mgmt 04.04.12Performance mgmt 04.04.12
Performance mgmt 04.04.12
 
Evidencias de consultas
Evidencias de consultasEvidencias de consultas
Evidencias de consultas
 
Expert Advice For Getting The Most Out Of Blogging
Expert Advice For Getting The Most Out Of BloggingExpert Advice For Getting The Most Out Of Blogging
Expert Advice For Getting The Most Out Of Blogging
 
USA Meganne's powerpoint
USA   Meganne's powerpointUSA   Meganne's powerpoint
USA Meganne's powerpoint
 
Observatoire de l'Internet mobile - SFR Régie
Observatoire de l'Internet mobile - SFR RégieObservatoire de l'Internet mobile - SFR Régie
Observatoire de l'Internet mobile - SFR Régie
 
Services for
Services for Services for
Services for
 
Amazing sider man
Amazing sider manAmazing sider man
Amazing sider man
 
Evaluation - Conventions
Evaluation - ConventionsEvaluation - Conventions
Evaluation - Conventions
 
Video gaming joy
Video gaming joyVideo gaming joy
Video gaming joy
 
Bitacoras tecno lab
Bitacoras tecno labBitacoras tecno lab
Bitacoras tecno lab
 
Evaluation
EvaluationEvaluation
Evaluation
 
In need of advice
In need of adviceIn need of advice
In need of advice
 

Semelhante a Auto mac rateless wireless concurrent medium access

06 fr technology-030420
06 fr technology-03042006 fr technology-030420
06 fr technology-030420jitendra Samal
 
New framing-protocols
New framing-protocolsNew framing-protocols
New framing-protocolsNitesh Singh
 
Asynchronous Transfer Mode ATM
Asynchronous Transfer Mode  ATMAsynchronous Transfer Mode  ATM
Asynchronous Transfer Mode ATMMadhumita Tamhane
 
Network protocols and vulnerabilities
Network protocols and vulnerabilitiesNetwork protocols and vulnerabilities
Network protocols and vulnerabilitiesG Prachi
 
Mediumaccesscontrol
MediumaccesscontrolMediumaccesscontrol
MediumaccesscontrolVk Sreedhar
 
Digital Transmission 1.ppt
Digital Transmission 1.pptDigital Transmission 1.ppt
Digital Transmission 1.pptrobomango
 
Transport protocols
Transport protocolsTransport protocols
Transport protocolsOnline
 
4G-Fourth Generation Mobile Communication System
4G-Fourth Generation Mobile Communication System4G-Fourth Generation Mobile Communication System
4G-Fourth Generation Mobile Communication SystemSafaet Hossain
 
8. TDM Mux_Demux.pdf
8. TDM Mux_Demux.pdf8. TDM Mux_Demux.pdf
8. TDM Mux_Demux.pdfTabrezahmed39
 
Cross-Layer Design of Raptor Codes for Video Multicast over 802.11n MIMO Chan...
Cross-Layer Design of Raptor Codes for Video Multicast over 802.11n MIMO Chan...Cross-Layer Design of Raptor Codes for Video Multicast over 802.11n MIMO Chan...
Cross-Layer Design of Raptor Codes for Video Multicast over 802.11n MIMO Chan...Berna Bulut
 
Introduction to Computer Networks
Introduction to Computer Networks Introduction to Computer Networks
Introduction to Computer Networks TechKev
 

Semelhante a Auto mac rateless wireless concurrent medium access (20)

06 fr technology-030420
06 fr technology-03042006 fr technology-030420
06 fr technology-030420
 
New framing-protocols
New framing-protocolsNew framing-protocols
New framing-protocols
 
Part5-tcp-improvements.pptx
Part5-tcp-improvements.pptxPart5-tcp-improvements.pptx
Part5-tcp-improvements.pptx
 
Asynchronous Transfer Mode ATM
Asynchronous Transfer Mode  ATMAsynchronous Transfer Mode  ATM
Asynchronous Transfer Mode ATM
 
Adhoc
AdhocAdhoc
Adhoc
 
Tcp
TcpTcp
Tcp
 
Network protocols and vulnerabilities
Network protocols and vulnerabilitiesNetwork protocols and vulnerabilities
Network protocols and vulnerabilities
 
Mediumaccesscontrol
MediumaccesscontrolMediumaccesscontrol
Mediumaccesscontrol
 
Chap24
Chap24Chap24
Chap24
 
Part9-congestion.pptx
Part9-congestion.pptxPart9-congestion.pptx
Part9-congestion.pptx
 
Digital Transmission 1.ppt
Digital Transmission 1.pptDigital Transmission 1.ppt
Digital Transmission 1.ppt
 
Transport protocols
Transport protocolsTransport protocols
Transport protocols
 
4G-Fourth Generation Mobile Communication System
4G-Fourth Generation Mobile Communication System4G-Fourth Generation Mobile Communication System
4G-Fourth Generation Mobile Communication System
 
AdHocTutorial.ppt
AdHocTutorial.pptAdHocTutorial.ppt
AdHocTutorial.ppt
 
Shubham chakravarty ppt_wcan
Shubham chakravarty ppt_wcanShubham chakravarty ppt_wcan
Shubham chakravarty ppt_wcan
 
8. TDM Mux_Demux.pdf
8. TDM Mux_Demux.pdf8. TDM Mux_Demux.pdf
8. TDM Mux_Demux.pdf
 
Cross-Layer Design of Raptor Codes for Video Multicast over 802.11n MIMO Chan...
Cross-Layer Design of Raptor Codes for Video Multicast over 802.11n MIMO Chan...Cross-Layer Design of Raptor Codes for Video Multicast over 802.11n MIMO Chan...
Cross-Layer Design of Raptor Codes for Video Multicast over 802.11n MIMO Chan...
 
Introduction to Computer Networks
Introduction to Computer Networks Introduction to Computer Networks
Introduction to Computer Networks
 
Atm presentation M.TECH ( PPT FILE )
Atm presentation M.TECH ( PPT FILE )Atm presentation M.TECH ( PPT FILE )
Atm presentation M.TECH ( PPT FILE )
 
3 rd sem atm M.TCH ( PPT FILE )
3 rd sem atm M.TCH ( PPT FILE )3 rd sem atm M.TCH ( PPT FILE )
3 rd sem atm M.TCH ( PPT FILE )
 

Último

Class 11th Physics NEET formula sheet pdf
Class 11th Physics NEET formula sheet pdfClass 11th Physics NEET formula sheet pdf
Class 11th Physics NEET formula sheet pdfAyushMahapatra5
 
Activity 01 - Artificial Culture (1).pdf
Activity 01 - Artificial Culture (1).pdfActivity 01 - Artificial Culture (1).pdf
Activity 01 - Artificial Culture (1).pdfciinovamais
 
Introduction to Nonprofit Accounting: The Basics
Introduction to Nonprofit Accounting: The BasicsIntroduction to Nonprofit Accounting: The Basics
Introduction to Nonprofit Accounting: The BasicsTechSoup
 
Energy Resources. ( B. Pharmacy, 1st Year, Sem-II) Natural Resources
Energy Resources. ( B. Pharmacy, 1st Year, Sem-II) Natural ResourcesEnergy Resources. ( B. Pharmacy, 1st Year, Sem-II) Natural Resources
Energy Resources. ( B. Pharmacy, 1st Year, Sem-II) Natural ResourcesShubhangi Sonawane
 
Advanced Views - Calendar View in Odoo 17
Advanced Views - Calendar View in Odoo 17Advanced Views - Calendar View in Odoo 17
Advanced Views - Calendar View in Odoo 17Celine George
 
Food Chain and Food Web (Ecosystem) EVS, B. Pharmacy 1st Year, Sem-II
Food Chain and Food Web (Ecosystem) EVS, B. Pharmacy 1st Year, Sem-IIFood Chain and Food Web (Ecosystem) EVS, B. Pharmacy 1st Year, Sem-II
Food Chain and Food Web (Ecosystem) EVS, B. Pharmacy 1st Year, Sem-IIShubhangi Sonawane
 
How to Give a Domain for a Field in Odoo 17
How to Give a Domain for a Field in Odoo 17How to Give a Domain for a Field in Odoo 17
How to Give a Domain for a Field in Odoo 17Celine George
 
ComPTIA Overview | Comptia Security+ Book SY0-701
ComPTIA Overview | Comptia Security+ Book SY0-701ComPTIA Overview | Comptia Security+ Book SY0-701
ComPTIA Overview | Comptia Security+ Book SY0-701bronxfugly43
 
PROCESS RECORDING FORMAT.docx
PROCESS      RECORDING        FORMAT.docxPROCESS      RECORDING        FORMAT.docx
PROCESS RECORDING FORMAT.docxPoojaSen20
 
Measures of Central Tendency: Mean, Median and Mode
Measures of Central Tendency: Mean, Median and ModeMeasures of Central Tendency: Mean, Median and Mode
Measures of Central Tendency: Mean, Median and ModeThiyagu K
 
Unit-IV; Professional Sales Representative (PSR).pptx
Unit-IV; Professional Sales Representative (PSR).pptxUnit-IV; Professional Sales Representative (PSR).pptx
Unit-IV; Professional Sales Representative (PSR).pptxVishalSingh1417
 
General Principles of Intellectual Property: Concepts of Intellectual Proper...
General Principles of Intellectual Property: Concepts of Intellectual  Proper...General Principles of Intellectual Property: Concepts of Intellectual  Proper...
General Principles of Intellectual Property: Concepts of Intellectual Proper...Poonam Aher Patil
 
Unit-V; Pricing (Pharma Marketing Management).pptx
Unit-V; Pricing (Pharma Marketing Management).pptxUnit-V; Pricing (Pharma Marketing Management).pptx
Unit-V; Pricing (Pharma Marketing Management).pptxVishalSingh1417
 
Explore beautiful and ugly buildings. Mathematics helps us create beautiful d...
Explore beautiful and ugly buildings. Mathematics helps us create beautiful d...Explore beautiful and ugly buildings. Mathematics helps us create beautiful d...
Explore beautiful and ugly buildings. Mathematics helps us create beautiful d...christianmathematics
 
Measures of Dispersion and Variability: Range, QD, AD and SD
Measures of Dispersion and Variability: Range, QD, AD and SDMeasures of Dispersion and Variability: Range, QD, AD and SD
Measures of Dispersion and Variability: Range, QD, AD and SDThiyagu K
 
Making and Justifying Mathematical Decisions.pdf
Making and Justifying Mathematical Decisions.pdfMaking and Justifying Mathematical Decisions.pdf
Making and Justifying Mathematical Decisions.pdfChris Hunter
 
Sociology 101 Demonstration of Learning Exhibit
Sociology 101 Demonstration of Learning ExhibitSociology 101 Demonstration of Learning Exhibit
Sociology 101 Demonstration of Learning Exhibitjbellavia9
 

Último (20)

Class 11th Physics NEET formula sheet pdf
Class 11th Physics NEET formula sheet pdfClass 11th Physics NEET formula sheet pdf
Class 11th Physics NEET formula sheet pdf
 
Activity 01 - Artificial Culture (1).pdf
Activity 01 - Artificial Culture (1).pdfActivity 01 - Artificial Culture (1).pdf
Activity 01 - Artificial Culture (1).pdf
 
INDIA QUIZ 2024 RLAC DELHI UNIVERSITY.pptx
INDIA QUIZ 2024 RLAC DELHI UNIVERSITY.pptxINDIA QUIZ 2024 RLAC DELHI UNIVERSITY.pptx
INDIA QUIZ 2024 RLAC DELHI UNIVERSITY.pptx
 
Introduction to Nonprofit Accounting: The Basics
Introduction to Nonprofit Accounting: The BasicsIntroduction to Nonprofit Accounting: The Basics
Introduction to Nonprofit Accounting: The Basics
 
Asian American Pacific Islander Month DDSD 2024.pptx
Asian American Pacific Islander Month DDSD 2024.pptxAsian American Pacific Islander Month DDSD 2024.pptx
Asian American Pacific Islander Month DDSD 2024.pptx
 
Energy Resources. ( B. Pharmacy, 1st Year, Sem-II) Natural Resources
Energy Resources. ( B. Pharmacy, 1st Year, Sem-II) Natural ResourcesEnergy Resources. ( B. Pharmacy, 1st Year, Sem-II) Natural Resources
Energy Resources. ( B. Pharmacy, 1st Year, Sem-II) Natural Resources
 
Advanced Views - Calendar View in Odoo 17
Advanced Views - Calendar View in Odoo 17Advanced Views - Calendar View in Odoo 17
Advanced Views - Calendar View in Odoo 17
 
Food Chain and Food Web (Ecosystem) EVS, B. Pharmacy 1st Year, Sem-II
Food Chain and Food Web (Ecosystem) EVS, B. Pharmacy 1st Year, Sem-IIFood Chain and Food Web (Ecosystem) EVS, B. Pharmacy 1st Year, Sem-II
Food Chain and Food Web (Ecosystem) EVS, B. Pharmacy 1st Year, Sem-II
 
How to Give a Domain for a Field in Odoo 17
How to Give a Domain for a Field in Odoo 17How to Give a Domain for a Field in Odoo 17
How to Give a Domain for a Field in Odoo 17
 
ComPTIA Overview | Comptia Security+ Book SY0-701
ComPTIA Overview | Comptia Security+ Book SY0-701ComPTIA Overview | Comptia Security+ Book SY0-701
ComPTIA Overview | Comptia Security+ Book SY0-701
 
PROCESS RECORDING FORMAT.docx
PROCESS      RECORDING        FORMAT.docxPROCESS      RECORDING        FORMAT.docx
PROCESS RECORDING FORMAT.docx
 
Measures of Central Tendency: Mean, Median and Mode
Measures of Central Tendency: Mean, Median and ModeMeasures of Central Tendency: Mean, Median and Mode
Measures of Central Tendency: Mean, Median and Mode
 
Unit-IV; Professional Sales Representative (PSR).pptx
Unit-IV; Professional Sales Representative (PSR).pptxUnit-IV; Professional Sales Representative (PSR).pptx
Unit-IV; Professional Sales Representative (PSR).pptx
 
General Principles of Intellectual Property: Concepts of Intellectual Proper...
General Principles of Intellectual Property: Concepts of Intellectual  Proper...General Principles of Intellectual Property: Concepts of Intellectual  Proper...
General Principles of Intellectual Property: Concepts of Intellectual Proper...
 
Unit-V; Pricing (Pharma Marketing Management).pptx
Unit-V; Pricing (Pharma Marketing Management).pptxUnit-V; Pricing (Pharma Marketing Management).pptx
Unit-V; Pricing (Pharma Marketing Management).pptx
 
Explore beautiful and ugly buildings. Mathematics helps us create beautiful d...
Explore beautiful and ugly buildings. Mathematics helps us create beautiful d...Explore beautiful and ugly buildings. Mathematics helps us create beautiful d...
Explore beautiful and ugly buildings. Mathematics helps us create beautiful d...
 
Measures of Dispersion and Variability: Range, QD, AD and SD
Measures of Dispersion and Variability: Range, QD, AD and SDMeasures of Dispersion and Variability: Range, QD, AD and SD
Measures of Dispersion and Variability: Range, QD, AD and SD
 
Making and Justifying Mathematical Decisions.pdf
Making and Justifying Mathematical Decisions.pdfMaking and Justifying Mathematical Decisions.pdf
Making and Justifying Mathematical Decisions.pdf
 
Sociology 101 Demonstration of Learning Exhibit
Sociology 101 Demonstration of Learning ExhibitSociology 101 Demonstration of Learning Exhibit
Sociology 101 Demonstration of Learning Exhibit
 
Mehran University Newsletter Vol-X, Issue-I, 2024
Mehran University Newsletter Vol-X, Issue-I, 2024Mehran University Newsletter Vol-X, Issue-I, 2024
Mehran University Newsletter Vol-X, Issue-I, 2024
 

Auto mac rateless wireless concurrent medium access

  • 1. Wireless Network Presentation AutoMAC (Rateless Wireless Concurrent Medium Access) Aditya Gudipati, Stephanie Pereira, Sachin Katti Standford University
  • 2. Presented on : Mobile Computing and Networking 2012 (MobiCom'12), August 22-26, 2012, Istanbul,Turkey.
  • 3. Current Wireless Design • Current Design : one Tx, one frequency, one at time (uplink and downlink) >> Avoid the interference • RTS/CTS/Backoff Mechanism (protocols overhead) >> Client need to sense the carrier, to avoid collision Limiting network throughput
  • 4. Proposed Wireless Design • Opposite approach : Exploit the interference • Multiple clients concurently Tx to AP (uplink) • AP concurently Tx to multiple clients (downlink) • Decode all constituent packets from interference Increasing network throughput
  • 5. Exploiting Interference (Uplink) y = h1x1+ h2x2 + N AP SIC (Successive Interference Cancelation) h1x1 x1 y A x2 B h2x2 + N h2x2
  • 6. Exploiting Interference (Uplink) • No Interference Troughput • Throughput for Client A Rsic > Rnint • Throughput for Client B • Throughput system gained extra throughput, without hurting ongoing Tx
  • 7. Exploiting Interference (Downlink) (x1 + x2) /√2 SNR High AP (Stronger Node) B y = h1x1 /√2 + h2x2 /√2 + N SIC (Successive Interference Cancelation) SNR Low (Weaker Node) A h1x1 /√2 y y = h1x1 /√2 + h2x2 /√2 + N h1x1 /√2 h2x2/√2+ N h2x2/√2
  • 8. Exploiting Interference (Downlink) • number Tx required by stronger client < weaker client to decode • dividing Tx power, instead of increasing • higher throughput when SNR different • throughput at the equal SNR ∼ no interference schemes
  • 9. Exploiting Interference (Downlink) Throughput A (Alice) and B (Bob) can be achieved by exploiting interference compare to interference avoidance scheme
  • 10. AutoMAC • Sender didn't know actual SINR at receiver for decoding ->Rateless Property >> Rateless Codes (send rateless Tx, until receiver can decode) • Wastefull Tx because packet can be decoded less than rateless encoding requirements >> Speculative ACKing (number rateless Tx depends on the SINR value)
  • 11. AutoMAC : MAC Design • Short Contention advertisement • announce the number of users send concurrently Tx in the next slot • not sent, if AP want to transmit or concurrent Tx in previous slot continue • Frequency domain backoff technique • client pickup random subcarrier
  • 12. AutoMAC : Exploit Uplink Interference • Packet Encoding • Orthogonal choice of rateless code (Strider or Spinal codes) • Decoding Constituent Packet with SIC • Per-frame channel estimation • Decoding Packet (Strider) • Substracting Node'1 collission contribution
  • 13. AutoMAC : Speculative ACKing • Diferrent encoding time -> encoding order and relative SNR between AP-Client • Number of Tx is less for last decoded packet than the first packet -> better SNR • "Key" of ACKing technique : • Estimate number of Tx for encoding packet -> estimate effective SNR value • SINR vs number Tx graph -> after M Tx, receiver start ACK packet p
  • 14. AutoMAC : Exploiting Broadcast on Downlink • same encoding technique for all client – rateless encoding (strider's) -> rateless frame – n frames add in complex domain -> one frame – prepend header, pass frame to OFDM PHY for Tx • decoding the own packet at last – every client assumed best channel – ensure SINR to decode and send the ACK -> AP receive know the received signal strength – apply the SIC in the order Tx from AP
  • 15. Evaluation outperform by 35% (include downlink) decode packet in interference upto 3 packets eleminates hidden terminal multiplex upto 3 packets (downlink) accurately estimates channel, frequency, and sampling offsets • 60% throughput gain over 802.11 MAC (uplink) and 50% over an 802.11 style MAC • • • • •
  • 16. Evaluation The Gains will increase as relative with SNR increase, and AutoMAC gain 50 - 60 % over Conventional or Time Fair Wifi.
  • 17. Evaluation Time Spent and throughput fairness comparison
  • 18. Gain Analysis • Collision minimum, because no lack of coordination and inability to decode -> Centralized MAC • Lower contention time -> frequency domain backoff technique • No overheads time for ACK waiting (SIFS,DIFS) -> ACK one for every batch • fraction time spent is higher 20% -> efficient MAC protocol