1. doc.: IEEE 802.15-<doc#>
<month year>
doc.: IEEE <doc#>
November 2007
Project: IEEE P Working Group for Wireless Personal Area Networks (WPANs)
Submission Title: MAC Enhancement and Cross-layer Information
Date Submitted: 13 Nov, 2007
Source: Seong-Soon Joo, YoungHwan Ham, Sang Joon Park, Cheol Sig Pyo
Company: ETRI
Address: 161 Gajeong-dong, Yuseong-gu, Daejeon, KOREA
Voice: , FAX: ,
Re:
Abstract: To clarify the scope of IEEE e, user requirements are extracted from the PAR for P e ( ), and constraints and criteria for alternative solutions are considered. As for MAC enhancements, the use of cross-layer information is suggested and an issue on the scope is raised.
Purpose: To raise an issue on the scope of IEEE e
Notice: This document has been prepared to assist the IEEE P It is offered as a basis for discussion and is not binding on the contributing individual(s) or organization(s). The material in this document is subject to change in form and content after further study. The contributor(s) reserve(s) the right to add, amend or withdraw material contained herein.
Release: The contributor acknowledges and accepts that this contribution becomes the property of IEEE and may be made publicly available by P
ETRI
<author>, <company>

2. MAC Enhancements and Cross-layer Information
<month year>
doc.: IEEE <doc#>
November 2007
MAC Enhancements and Cross-layer Information
Seong-Soon Joo*, YoungHwan Ham,
Sang Joon Park, Cheol Sig Pyo
ETRI
ETRI
<author>, <company>

3. doc.: IEEE 802.15-<doc#>
<month year>
doc.: IEEE <doc#>
November 2007
Task of the P e
Problem to be solved in P e
What is the problem to be solved in e ?
Formulate problem: current state  desired state, requirements
Analyze problem: constraints, criteria to be used in evaluating solutions
Search alternative solutions, Select the preferred solution, Specify
Found in e PAR
What are requirements, constraints, criteria for the problem?
Purpose: User requirements
determinism, mixed service, reliability, power efficiency, fast recovery, low latency, direct RFD communication
Scope: Preferred solutions
TDMA, channel hopping, improved CSMA, flexible GTS, asymmetrical keys, (latency ?)
Enough detailed requirements? Where are the constraints and criteria?
ETRI
<author>, <company>

4. doc.: IEEE 802.15-<doc#>
<month year>
doc.: IEEE <doc#>
November 2007
SG4e Purpose
Study group investigating MAC enhancements such as:
Support for Determinism
e.g. TDMA supporting from a few to 10,000s slots
Mixed service and power savings levels in one network (dynamic transmit power control)
Frequency diversity for retransmissions for improved reliability
Low duty cycle operation with beacons for power efficiency
Distributed management of time slots and frequency hopping patterns for fast recovery from regional failures
2ms per hop latency including 1 retransmission
Direct communication between Reduced Functionality Devices in the network
ETRI
<author>, <company>

5. doc.: IEEE 802.15-<doc#>
<month year>
doc.: IEEE <doc#>
November 2007
Scope
The intention of this amendment is to enhance and add functionality to the MAC to a) better support the industrial markets and b) permit compatibility with modifications being proposed within the Chinese WPAN.
Specifically, the MAC enhancements to be considered will be limited to the following:
TDMA - to provide:
determinism,
enhanced utilization of bandwidth
Channel Hopping - to provide additional robustness in high interfering environments and enhance coexistence with other wireless networks
GTS - to increase its flexibility such as:
supporting peer to peer,
the length of the slot, and
number of slots
CSMA - to improve throughput and reduce energy consumption
Security - to add support for additional options such as asymmetrical keys
Low latency - to reduce end to end delivery time such as needed for control applications
ETRI
<author>, <company>

6. Refine the Requirements
<month year>
doc.: IEEE <doc#>
November 2007
Refine the Requirements
User requirements
Determinism: how much accurate in synchronization is needed ?
Mixed service: what levels of services are required ?
Reliability: how reliable in terms of the loss rate is guaranteed ?
Power efficiency: how much improved compare to ?
Fast recovery: how fast converged on self-organizing ?
Low latency: 2ms per hop including 1 retransmission
Direct RFD communication
Any other requirements ?
Specify the goals of P e
Improve performance in accessing media and networking
latency, loss rate, fast recovery, power saving
Support multiple grades of services
latency jitter, loss rate, security level on data transmission
New features
direct RFD communication, …
ETRI
<author>, <company>

7. doc.: IEEE 802.15-<doc#>
<month year>
doc.: IEEE <doc#>
November 2007
Constraints, Criteria
Constraints
Maintain primitives on the service access points of
physical layer, service specific convergence sublayer, management layer
PD-SAP, MCDS-SAP, MLNE-SAP, PHY PIB, MAC PIB
Additional features, do not make conflicts with the
independent features
use of information provided through the SAPs of
require to modify the primitive on the SAP ??
require to invent new primitives on the SAP ?
Criteria
Measures on achieved level to the requirements
latency, latency jitter, loss rate, power, convergence time, power saving, reliability, …
Complexity of the solution
cost, …
ETRI
<author>, <company>

8. Possible Alternative Solutions
<month year>
doc.: IEEE <doc#>
November 2007
Possible Alternative Solutions
Considering the criteria with the specified requirements
latency, latency jitter, loss rate, power saving, fast recovery, …
TDMA, channel hopping, improved CSMA, flexible GTS
require to modify primitives or to invent primitives ?
Use of the cross-layer information
Information from network layer
topology information
Nonbeacon-enabled mode is more flexible, but cannot support wakeup & sleep
If scheduled without beacon by using topology information, energy saved low latency can be achieved
Information from physical layer
signal detection
If detects the event, asynchronized MAC can be introduced
power consumption when only need time, low latency, reliable support with channel hopping
ETRI
<author>, <company>

9. doc.: IEEE 802.15-<doc#>
<month year>
doc.: IEEE <doc#>
November 2007
Conclusions
Formulate the problem more rigorously before going further
Requirements
Constraints
Criteria
Check the limitation on MAC enhancement, while maintaining compatibility
PD-SAP, MCDS-SAP, MLNE-SAP, PHY PIB, MAC PIB
Use of the cross-layer information
Extend views on alternative solutions
Channel hopping
TDMA, topology aware TDMA scheduling
Improved CSMA, asynchronous MAC with signal detection
Flexible GTS, asymmetric key
ETRI
<author>, <company>