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ARQ Proxy: Cross-Layer Error Recovery in Wireless Access Networks

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Jan 5, 2010 ARQ Proxy: Cross-Layer Error Recovery in Wireless Access Networks Dzmitry Kliazovich ERCIM Fellow University of Luxembourg ... – PowerPoint PPT presentation

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Title: ARQ Proxy: Cross-Layer Error Recovery in Wireless Access Networks


1
ARQ Proxy Cross-Layer Error Recovery in Wireless
Access Networks
Jan 5, 2010
  • Dzmitry Kliazovich
  • ERCIM Fellow
  • University of Luxembourg

2
TCP over Infrastructure WiFi
WiFi
(IEEE 802.11)
IP Network
Base Station
Mobile Node
(MN)
(BS)
Application Data
Channel Contention
Acknowledgements at different layers
3
ARQ Proxy - Approach
  • Idea Substitute the transmission of TCP ACK
    packets with a short MAC layer request on the
    radio link for multilayer ARQ overhead reduction

4
ARQ Proxy - Approach
IP Network
Fixed Host
Base Station
Mobile Node
(
FH
)
(MN)
(BS)
ARQ
Proxy
MAC
ARQ
Client
MAC
TCP
TCP
  • Access TCP header
  • Get IP addr, port, etc.
  • Generate TCP ACK store

Generate TCP ACK
TCP ACK Index
TCP ACK Index
  • Compute TCP ACK identification index

5
ARQ Proxy Packet Identification
  • Hash values
  • Frame Sequence Numbers

PHY
LL
TCP data
Header
Header
Sequence
Address 3
Address 4
Control
B15
B3
B4
B0
Fragment
Sequence Number
Number
4
12
Bits
  • Link layer ACK (LL-ACK)

or
Base Station
Mobile Node
(MN)
(BS)
6
ARQ Proxy - Benefits
  • Performance and System Capacity Increase

WiFi
(IEEE 802.11)
IP Network
Base Station
Mobile Node
(MN)
(BS)
Channel Contention
Overhead reduction
7
ARQ Proxy - Benefits
  • Reduced RTT (Round Trip Time)

IP Network
Fixed Host
Base Station
Mobile Node
(
FH
)
(MN)
(BS)
Medium Access TCP ACK Transmission over
wireless channel
8
ARQ Proxy - Benefits
  • End-to-end TCP semantics are maintained

IP Network
Fixed Host
Base Station
Mobile Node
(
FH
)
(MN)
(BS)
9
ARQ Proxy - Benefits
  • Higher channel error rates tolerance

Wired channel (BER 10-6 to 10-8)
Wireless channel (BER 10-3 to 10-1)
IP Network
Fixed Host
Base Station
Mobile Node
(
FH
)
(MN)
(BS)
No TCP ACK over wireless channel
10
ARQ Proxy - Benefits
  • Mobility Incremental deployment

No TCP state related information is maintained
IP Network
Fixed Host
Base Station
Mobile Node
(
FH
)
(MN)
(BS)
ARQ
Proxy
ARQ
Client
11
ARQ Proxy - Benefits
  • Performance and system capacity increase
  • Reduced RTT (Round Trip Time)
  • End-to-end TCP semantics are maintained
  • Higher channel error rates tolerance
  • Full mobility support
  • Incremental deployment Co-existence

12
ARQ Proxy - Limitations
  • TCP ACKs are not substituted
  • During connection establishment and connection
    termination packets (identified by SIN and FIN
    flags)
  • For TCP ACK encapsulated into TCP data packet in
    case of bidirectional data transfer
  • For Duplicate TCP ACKs
  • TCP ACK advertising exhausted receive buffer
    resources (rwnd field)

13
Motivation Market Trends
14
Motivation for Scenario Choice
  • Why link layer ARQ as a feedback channel?
  • Why TCP?
  • Accounts for more than 85 of Internet traffic
  • Why Infrastructure network scenario?
  • Over 95 of wireless links are on the last mile

C. Fraleigh at el. Packet-level traffic
measurements from the Sprint IP backbone, IEEE
Network, vol. 17, no. 6, pp. 6 16, Nov.-Dec.
2003.
15
Other Operation Scenarios
ARQ Proxy
ARQ Proxy
  • Single-hop Ad hoc network
  • Multi-hop network
  • Infrastructure network with relays

16
Market Trends
  • Outstanding trends in networking
  • Tremendous growth of Internet
  • Evolution of the network access toward the use of
    wireless technologies
  • Currently, number of wireless subscribers
    overcomes the number of Internet users by more
    than two times

Sources Ericsson, Inc. and Internet World Stats
(www.internetworldstats.com)
17
Generalization Distributed Protocol Stacks
18
TCP/IP optimization in Heterogeneous Networks
  • Cross-Layering
  • Allows awareness and cooperation between protocol
    layers
  • Joint, coupled design
  • Agent-Based Networking
  • Aims at introduction of active functionalities in
    the passive network core
  • Examples Web-proxy, cashing proxy

19
Concept
Layered Design
Cross-Layering
Agent-based Networking
Distributed Protocol Stacks
  • Idea To extend the concept of protocol stack
    modularity making it network-wide

20
Distributed Protocol Stacks
  • Design Details
  • Outsource protocol stack functions into the
    network
  • Maintain communication between the detached block
    and the host protocol stack

21
ARQ Proxy
Bottleneck link
IP network
File Server
User Terminal
Base station
TCP data
Transport
Transport
Output()
TCP ACKs
TCP ACKs
ACK gen
Module running environment
Network
Network
Link
Link
Link
Link
Physical
Physical
Physical
Physical
Custom protocol
22
Evaluation Results
  • Simulation Setup
  • Ns2 simulator with ARQ proxy extensions
  • IEEE 802.11b physical layer, no RTS/CTS
  • Bottleneck buffer 700 packets
  • TCP NewReno flows
  • Results averaged over 10 runs

IEEE 802.11b _at_ 11 Mb/s
100 Mb/s, 15 ms
Fixed Host
Mobile Node
Base Station
23
Evaluation Results
  • Throughput performance

Improvement 20
Improvement up to 100
VoIP and Multimedia Applications
TCP file transfer, Ethernet MTU
24
Evaluation Results
  • Round Trip Time (RTT) improvement

Order of milliseconds
25
Evaluation Results
  • High error rate tolerance

26
ARQ Proxy for 3G LTE
  • 3G Long-Term Evolution (LTE)
  • Key features
  • Evolved radio access OFDM, multiple antenna
    techniques
  • Evolved architecture fewer nodes, reduced
    latency, low cost
  • Evolved networking All-IP architecture, shared
    resources

D. Kliazovich, F. Granelli, S. Redana and N.
Riato, "Cross-Layer Error Control Optimization in
3G LTE," IEEE Global Communications Conference
(GLOBECOM), Washington, DC, U.S.A, December 2007.
27
ARQ Proxy for 3G LTE
  • ARQ Proxy Use Hybrid ARQ (HARQ) feedback to
    substitute TCP ACK packets on the radio channel
  • Hash values for packet identification

Protocol stack at the receiver
28
Evaluation 3G LTE scenario
  • Setup
  • Ns2 with Enhanced UMTS Radio Access Extensions
    (EURAE)
  • eNB and RNC are combined into a single node
  • Rayleigh fading with 300 meters between UE and
    eNB
  • Encapsulation overhead TCP (20 bytes), IP (20
    bytes), PDCP (1 byte), RLC (2 bytes), and PHY CRC
    (2 bytes)
  • Hash value size 32 bits
  • TCP NewReno sources
  • Metrics
  • Throughput and Round Trip Time (RTT) performance
    with different error rates

29
Evaluation 3G LTE scenario
  • Round Trip Time (RTT)
  • Hash value errors

30
Current Activities and Future Work
  • ARQ proxy material
  • ARQ proxy for WiFi (IEEE 802.11)
  • ARQ proxy for 3G LTE (Super-3G)
  • ARQ proxy for WiMAX (IEEE 802.16)
  • D. Kliazovich, N. Ben Halima, and F. Granelli,
    "Cross-Layer Error Recovery Optimization in WiFi
    Networks," Tyrrhenian International Workshop on
    Digital Communication (TIWDC), Ischia island,
    Naples, Italy, September, 2007.
  • D. Kliazovich, F. Granelli, S. Redana and N.
    Riato, Cross-Layer Error Control Optimization in
    3G LTE, IEEE GLOBECOM, Washington, DC, U.S.A,
    December 2007.
  • D. Kliazovich, T. Beniero, S. Dalsass, F.
    Serrelli, S. Redana, and F. Granelli,
    "Cross-Layer Error Control Optimization in
    WiMAX, IEEE GLOBECOM, New Orleans, LA, U.S.A,
    December 2008.

31
Current Activities and Future Work
  • ARQ proxy material
  • EU patent
  • Proposal to 3GPP standardization group
  • Under consideration for next generation equipment
    produced by Nokia Siemens Network (NSN)
  • D. Kliazovich, F. Granelli, S. Redana, and N.
    Riato, Cross-Layer Error Recovery Optimization
    for 3G LTE Systems, EP 07425087.9

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32
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