SDR 04 04 Phoenix Phoenix SDR Modular Link Layer Functions of - - PowerPoint PPT Presentation

▶
sdr 04 04 phoenix phoenix sdr
SMART_READER_LITE
LIVE PREVIEW

SDR 04 04 Phoenix Phoenix SDR Modular Link Layer Functions of - - PowerPoint PPT Presentation

Apr 05, 2023 178 likes •312 views

SDR 04 04 Phoenix Phoenix SDR Modular Link Layer Functions of Modular Link Layer Functions of a Generic Protocol Stack for a Generic Protocol Stack for Future Wireless Systems Future Wireless Systems L. Berlemann, A.

slide-1
SLIDE 1
  • L. Berlemann, ComNets, RWTH Aachen University

Modular Link Layer Functions of Modular Link Layer Functions of a Generic Protocol Stack for a Generic Protocol Stack for Future Wireless Systems Future Wireless Systems

  • L. Berlemann, A. Cassaigne, R. Pabst and B. Walke

Chair of Communication Networks (ComNets) RWTH Aachen University, Germany 2004 Software Defined Radio Technical Conference and Product Exposition, November 17th 2004, Phoenix, USA

SDR SDR’ ’04 04 – – Phoenix Phoenix

slide-2
SLIDE 2

2

  • L. Berlemann, ComNets, RWTH Aachen University

Overview Overview

  • Introduction and Motivation
  • Generic Protocol Stack in the Context of

Multi-Mode Capable Wireless Networks

  • Modular Approach
  • Realization of Protocol Layers
  • Conclusion and Outlook

Overview – Introduction – Generic Stack – Modular Approach - Realization - Outlook

slide-3
SLIDE 3

3

  • L. Berlemann, ComNets, RWTH Aachen University

Introduction Introduction and Motivation and Motivation

  • Idea: Protocols share a lot of communalities, that can be

exploited in an efficient reconfigurable wireless system Generic Protocol Stack

  • Advantages: runtime reconfigurability, maintainability,

code/resource sharing and accelerated protocol development through reusability

  • Generic part is crucial: Tradeoff - general usability vs.

implementation effort

  • Two approaches for realization, depending on the

abstraction level of identified similarities: – Parameterizable modules including fundamental protocol functions – Inheritance of generic part(s) [1]

Overview – Introduction – Generic Stack – Modular Approach - Realization - Outlook

[1] M. Siebert, B. Walke, “Design of Generic and Adaptive Protocol Software (DGAPS),” in Proc. of 3Gwireless '01, San Francisco USA, June 2001

slide-4
SLIDE 4

4

  • L. Berlemann, ComNets, RWTH Aachen University
  • Integration to a system specific protocol/layer (step 3)

– merging of generic and specific parts (modular composition or inheritance)

  • Development of standard-specific supplements (step 2)

– features and functions unique to the respective system technology – representation of the individual behavior of a system

  • Identification of similarities (step 1)

– layer by layer analysis – extraction of common features

  • Protocol Reconfigurability (step 4)

– Combined with reconfiguration management and functions: a flexible as well as efficient realization of a reconfigurable protocol stack

  • Generic Protocol Stack

– provides characteristics for all systems – will serve as a basis for future software design (reusability)

1. 2. 3. 4.

Generic Protocol Stack Generic Protocol Stack

Overview – Introduction – Generic Stack – Modular Approach - Realization - Outlook

slide-5
SLIDE 5

5

  • L. Berlemann, ComNets, RWTH Aachen University

Enabling Transition between Multiple Modes Enabling Transition between Multiple Modes

… with the help of a Modes Convergence Protocol.

  • Separation into specific/generic part in each layer
  • Management of (parallel existing) protocol stack/layer
  • Administration of user data (seamless mode transition)
  • Cross layer optimization (preservation of protocol status info)
  • Support of network-initiated reconfiguration

Overview – Introduction – Generic Stack – Modular Approach - Realization - Outlook

protocol stack mode 1 common part specific part transition RLC PHY1 MAC1 MAC protocol stack mode 2 common part specific part RLC PHY2 MAC2 MAC

management-plane user-plane + control-plane

cross stack management including modes convergence protocol protocol status information specific part PHY2 MAC2

slide-6
SLIDE 6

6

  • L. Berlemann, ComNets, RWTH Aachen University

Generic Protocol Functions of the Data Link Layer Generic Protocol Functions of the Data Link Layer

  • Modern communication protocols cannot be forced into

classical layered architecture of ISO/OSI RM

  • Though belonging to Data Link Layer, common fundamental

protocol functions can be found in multiple layers (2-4):

  • Error handling - Forward Error Correction or Automatic

Repeated reQuest protocols [2]

  • Flow control
  • Segmentation, concatenation and padding of PDUs*
  • Multiplexing and De-Multiplexing
  • Dynamic Scheduling
  • Ciphering
  • Header Compression

[2] L. Berlemann, A. Cassaigne and B. Walke, “Generic Protocol Functions for Design and Simulative Performance Evaluation of the Link-Layer for Reconfigurable Wireless Systems,” in Proc. of WPMC’04, Abano Terme Italy, September 2004

Overview – Introduction – Generic Stack – Modular Approach - Realization - Outlook

slide-7
SLIDE 7

7

  • L. Berlemann, ComNets, RWTH Aachen University

Modular Approach Modular Approach

  • Common protocol functions as parameterizable modules and system-

specific modules form a complete protocol layer

  • Communication inside: generic service primitives and generic PDUs
  • Functional Module: Realizes funda-

mental functionality as black box

  • Manager: Composition, rearrange-

ment, parameterization and data query of modules; Administration

  • f internal communication
  • Interface: Translation of generic

service primitives to specific ones

  • Service Access Point: Is needed, if

a classical layer is demanded for fitting into ordinary stack Simulation and performance evaluation on several levels: (sub-)layer as well as complete protocol stack

Overview – Introduction – Generic Stack – Modular Approach - Realization - Outlook

slide-8
SLIDE 8

8

  • L. Berlemann, ComNets, RWTH Aachen University

Parameterization of Functional Modules Parameterization of Functional Modules

Parameterization implies:

  • Specification of a value
  • Switching on/off of a behavior or functionality
  • Extension of the modules’ interface

Segmentation module as example:

  • Use of concatenation
  • Targeted PDU size after handling
  • Use of Padding, i.e. filling up of a PDU to reach a certain

size

  • Transmitter/Receiver Role
  • Buffer size for SDUs concatenated in a single PDU
  • Behavior in case of an error, i.e. interworking with ARQ

module

Overview – Introduction – Generic Stack – Modular Approach - Realization - Outlook

slide-9
SLIDE 9

9

  • L. Berlemann, ComNets, RWTH Aachen University

Exemplary Protocol Layers Exemplary Protocol Layers

UMTS RLC TCP/UDP/IP 802.11 MAC

Overview – Introduction – Generic Stack – Modular Approach - Realization - Outlook

slide-10
SLIDE 10

10

  • L. Berlemann, ComNets, RWTH Aachen University

channel utilization:

Segmentation Module as Example Segmentation Module as Example

SDU is separated into PDUs to fit to transport channel Here: Segmentation aspects of UMTS RLC in Unacknowledged Mode

  • Protocol overhead vs. optimized channel utilization
  • The segmentation module reflects the known behavior it can be

legitimately used in an multi-mode capable protocol stack

packet size of payload is increased increased channel utilization additional channel required Overview – Introduction – Generic Stack – Modular Approach - Realization - Outlook packet size of payload is increased fixed capacity of a channel fixed segmentation size payload / channel capacity = channel utilization protocol overhead with concatenation protocol overhead without concatenation

payload

payload l packet size

l payload channel capacity packet size =    ฀

50 100 150 200 250 300 350 400 450 500 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1

channel utilization, packet segmentation size of channel = 128 Byte payload packet size l

payload [Byte]

payload/channel capacity

sim.: with concatenation sim.: without concatenation analyt.: with concatenation analyt.: without concatenation

1st channel 2nd channel 3rd channel 4th channel

slide-11
SLIDE 11

11

  • L. Berlemann, ComNets, RWTH Aachen University

Conclusion and Outlook Conclusion and Outlook

  • The identified similarities are decisive for success

tradeoff of genericity

  • Generic protocol stack takes up well-proven and known

fundamental protocol functions

  • Existing (as shown) and future protocols (4G) can be

composed out of adequately parameterized modules

  • Library of common functions results in a construction kit for

accelerated protocol development

  • Efficient protocol reconfigurability through parameterization

is enabled on the basis of functional modules The introduced approach is a first step to an efficient multi-mode capable wireless system

Overview – Introduction – Generic Stack – Modular Approach - Realization - Outlook

slide-12
SLIDE 12

12

  • L. Berlemann, ComNets, RWTH Aachen University

Thank you for your attention ! Lars Berlemann ber@comnets.rwth-aachen.de

slide-13
SLIDE 13

13

  • L. Berlemann, ComNets, RWTH Aachen University

EW EW’ ’05 05

11th European Wireless Conference

Nicosia, Cyprus April 10 - 13, 2005 http://www.european- wireless2005.de

PIMRC 2005 PIMRC 2005

The 16th Annual IEEE International Symposium on Personal Indoor and Mobile Radio Communications

Maritim Hotel, Berlin, Germany September 11 – 14, 2005 http://www.pimrc2005.de

“Next Generation Wireless and Mobile Communications and Services”