1. Project: IEEE P802.15 Working Group for Wireless Personal Area Networks (WPANs)
Submission Title: Towards Ultra Low Power Sensor Networks
Date Submitted: March 2012
Source Kiran Byram, Shahriar Emami, Youngsoo Kim, Samsung; Chiu Ngo, Chunhui (Allan) Zhu, Samsung ; Liang Li, Vinno Technologies; Betty Zhao, Huawei, Myung; J. Lee, CUNY.
Re:
Abstract:
Purpose: To request to establish a study group to investigate potential amendment to for Ultra low power applications
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 1 1

2. Towards Ultra Low Power Sensor Networks
March 2012 2

3. Desirable Sensor Networks Attributes
Small node size
Power efficient nodes
High reliability
Use of globally available unlicensed band (such as 2.4 GHz) 3

4. WSN Applications/Standards
Typical
Data Rate
(kbps)
Typical Range
(m)
Existing
Standard(s)
Healthcare 30
/ /BT LE
Inventory Management
1000 – 4000
100
BT/ /BT
Home Automation
250 – 1000
Industrial Automation
For different applications of wireless sensors, there exists some technology in place to achieve the purpose
Most of these applications are addressed by IEEE 4

5. Power Analysis of Sensor Nodes
Power consuming elements
in sensor nodes
Sensing
Actuation
Logging the data into memory
Communication
Clustering
Processing
Communication energy consumption is almost 50% of the overall sensor node power consumption [3] 5

6. Power Consumption Figures for IEEE 802.15.4
Vendor
Chipset
Rx Power
Tx Power (0 dBm)
Sleep Mode Power
Vendor #1
Chipset #1 V
25.8 3V
4 μW
Vendor #2
Chipset # 2 V v
Vendor #3
Chipset # 3 V
15 3V
The existing silicon for IEEE require mW in transmit or receiver modes. 6

7. Power Consumption
Long battery life and small form factor are vital for a number of applications.
Analog RF front end consumes most of the power. Baseband requires far less.
Questions:
What are the RF architecture choices?
Are there any difference among them in terms of power consumption? 7

8. RF Architecture Options
Low IF
Uncertain IF
Sliding IF
Super Regenerative Receiver 8

9. Power Consumption RF Architecture Support for Modulation Rx Power
Supply
Voltage
Low IF
Coherent/
Non-coherent
> = 30 mW [4]
3 V
Sliding IF
8.5 mW [7]
1.2 V
Super Regenerative RF
2-3 mW [2]
Uncertain IF
52 mW [1]
0.5 V 9

10. Summary
The power consumption of various RF architectures are not the same.
Some architectures have limitations on the modulation type.
RF architectures that support non-coherent modulations are significantly more power efficient compared to the ones that support both modulation types.
Air interface should be designed to enable ultra low power consumption front ends. 10

11. Will The Existing PHYs Work?
Non-coherent modulation, for both payload and sync, can support ultra low power RF front ends
Two PHY options defined in 2.4 GHz spectrum use coherent modulation which is not good for low power
ASK PHY cannot be reused as is due to BPSK preamble and robustness issues 11

12. IEEE 802.15.4 PHY Type Supported Bands (MHz) Data Rate Preamble
Modulation
O-QPSK PHY
2450, 915, 868,
780 MHz
250 kbps for 2450, 915, 868 MHz bands and 100 kbps for 780 MHz band
BPSK PHY
868, 915 and 950 MHz
20 kbps for 868/950 MHz and 40 kbps for 915 MHz band
BPSK
ASK PHY
868,915 MHz band
250 kbps in 868 MHz
CSS PHY
2450 MHz band
1 Mbps /250 kbps optional
Chirp modulation
UWB PHY
3.1 to 10.6 GHz
100 kbps to 27 Mbps
Ternary codes (OOK, Phase modulated)
GFSK
950 MHz
100 kbps
New PHY
2.4 GHz
100 kbps - 1Mbps
TBD 12

13. Proposed Changes to IEEE 802.15.4
To add a new physical layer to IEEE for ultra low power (ULP) technologies in 2.4 GHz spectrum
This work will define a new 2.4 GHz PHY of IEEE
Necessary enhancements in MAC to support the new PHY 13

14. References
[1] N. M. Pletcher, S. Gambini and J. Rabaey, “A 52 micro-W Wake-Up Receiver With -72 dBm Sensitivity Using an Uncertain-IF Architecture,” IEEE Journal of Solid-State Circuits, vol. 44, no. 1, Jan
[2] F. X. Moncunill-Geniz, P. Palà-Schönwälder, and O. Mas-Casals, “A generic approach to the theory of superregenerative reception,” IEEE Trans. Circuits Syst. I, vol. 52, no. 1, pp. 54–70, Jan
[3] < >.
[4] <
[5] <
[6] <
[7] N. Stanic, A. Balankutty, P. R. Kinget and Y. Tsivids,”A 2.4-GHz ISM-band sliding-IF receiver
with a 0.5-V supply,” IEEE Journal of solid-state circuits, vol. 43, no. 5, May 2008. 14