1. Introduction
Application type | Device | Power consumption | Data rate |
---|---|---|---|
Implanted | Endoscope capsule | Low very | Medium |
Deep brain stimulator | Low | Low | |
Drug delivery capsule | Low | Low | |
Brain liquid pressure sensor | Very low | Low | |
Glucose sensor | Very low | Low | |
Wearable | ECG | Low | Low |
EMG | Low | Low | |
EEG | Low | Low | |
Blood pressure monitor | Low | Low | |
Hear rate monitor | Low | Low | |
pH monitor | Low | Low | |
SpO2 | Low | Low | |
Mp3 player | High | Medium | |
MP4, video player | High | High | |
Games | Hgih | High |
2. Wakeup radio concept and motivation
2.1. Wakeup radio
-
Wakeup radio hardware is simple to design and implement
-
Extracts energy from the radio signals
-
Provides wakeup signals to the network node without using internal power supply
-
Does not respond to normal data communication, and does not prematurely wakeup the sleeping node
2.2. Motivation
-
Minimize power consumption to increase the lifetime of the nodes
-
Maximize sleep time for a node
-
Minimize unnecessary wakeup periods to save power
-
Minimize overheads (e.g. control packets overheads) in the network
-
Minimize idle listening time
-
Minimize collision and retransmission of a packet
-
Minimize delay
-
Efficient and quick response to emergency situations with minimum delay
-
Fixed duty cycle MACs
-
Adaptive duty cycle MACs
-
Synchronous duty cycle MACs
-
Asynchronous duty cycle MACs
Parameters | TDMA | CSMA/CA |
---|---|---|
Power consumption | Low | High |
Bandwidth utilization | Maximum | Low |
Preferred traffic level | High | Low |
Dynamic (network change) | Poor | Good |
Effect of packet failure | Latency | Low |
Synchronization | Crucial | Not crucial |
3. Proposed model and methodology
3.1. Traffic assumption
3.2. BAN devices and states
Device | Periodic traffic | Random traffic |
---|---|---|
BN | Receives wakeup radio signal from BNC | Sends a wakeup radio signal to BNC |
BNC | Sends wakeup radio signal to BN | Receives wakeup radio signal from BN |
4. Wakeup process and scheduling mechanisms
4.1. Wakeup scheduling for periodic traffic
BAN nodes | Node Id | Inter-arrival time (s) |
---|---|---|
Heart rate monitor | BN-001 |
i
|
BP monitor | BN-002 |
j
|
Glucose monitor | BN-003 |
k
|
SpO2 | BN-004 |
l
|
EEG | BN-005 |
m
|
ECG | BN-006 |
n
|
pH monitor | BN-007 |
o
|
Temperature monitor | BN-008 |
p
|
Insulin pump | BN-009 |
q
|
4.2. Wakeup scheduling for random (emergency) traffic
4.3. Resource allocation
5. Analysis and simulation
5.1. Analysis
Variable | Explanation |
---|---|
P
tx
| Power required for TX (transmission) |
P
rx
| Power required for RX (reception) |
T
data
| Time required for data packet transmission |
T
ack
| Time required for Ack packet transmission |
T
b
| Time required for Beacon packet transmission |
P
t
| Power required to switch the transceiver between RX and TX |
T
t
| Time required to switch the transceiver between RX and TX |
N
| Number of one hop neighboring nodes |
P
active
| Power consumption in active state |
R
| Data rate of the radio |
L
x
| Length of a frame x, where x ∈ {data, ack, beacon, wakeup} |
P
tr
| Power required to turn on the transceiver from sleep state into the RX or TX state |
T
tr
| Time required to turn on the transceiver from sleep state into the RX or TX state |
θ
| Crystal tolerance of a wakeup timer |
T
cca
| Time required for CCA or carrier sensing |
P
sl
| Power consumed in sleep state |
P
twbn
| Power required to transmit low power wakeup packet |
P
rwbn
| Power required to receive low power wakeup packet |
T
wbn
| Time required to send low power wakeup packet |
P
twack
| Power required to transmit low power Ack packet |
T
wk
| Interval between preamble/beacon samplings |
T
sl
| Time spend in sleep state |
T
p
| Preamble duration |
T
wkrx
| Interval between preamble samplings in X-MAC |
N
probe
| Expected preamble-listen iterations required |
T
| Total time duration |
T
px
| Average number of preambles during time T |
5.1.1. B-MAC
5.1.2. X-MAC
5.1.3. WiseMAC
5.1.4. ZigBee MAC
5.1.5. Proposed MAC
5.2. BAN network setup for simulations
5.3. Results and discussion
Common parameters | |||||
---|---|---|---|---|---|
P
tx
| 27 mW |
P
active
| 0.005 mW |
L
beacon
| 10 Bytes |
P
rx
| 1.8 mW |
R
| 25 kb/s |
L
ack
| 10 Bytes |
T
data
| 16 ms |
L
data
| 50 Bytes |
L
wup
| 8 Bytes |
T
ack
| 3.2 ms |
P
tr
| 0.004 mW |
N
| 10 |
T
b
| 3.2 ms |
T
tr
| 0.8 ms |
θ
| 30 ppm |
P
t
| 14.39 mW |
T
cca
| 3 ms | ||
T
t
| 0.4 ms |
P
sl
| 0.004 mW |
Proposed MAC | Wise MAC | X-MAC | |||
---|---|---|---|---|---|
P
twbn
| 1.4 mW |
T
wk
| 400 ms |
T
wkrx
| 43.35 ms |
P
rwbn
| 0.4 mW |
T
p
| 20 ms |
T
P
| 2.41 ms |
T
wbn
| 2.56 ms |
B-MAC
|
N
probe
| 3.86 ms | |
P
twack
| 1.4 mW |
T
wk
| 400 ms | ||
T
wk
| 5.12 ms |
T
p
| 86.7 ms |