How can radio technology adapt to difficult …...2017/01/23 · Qualcomm Incorporated includes...
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How can radio technology adapt to difficult environments? Robin Heydon Senior Director, Technology Qualcomm Technologies International, Ltd. January 23 rd 2017
Transcript of How can radio technology adapt to difficult …...2017/01/23 · Qualcomm Incorporated includes...
How can radio technology adapt to difficult environments?
Robin Heydon
Senior Director, Technology
Qualcomm Technologies International, Ltd.
January 23rd 2017
Difficult Radio Environments?
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What is the most difficult radio environment?
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Each spec adds something new to help mitigate difficult radio environments
Case Study : Bluetooth® wireless technology
spec version example major features mitigation strategy
v1.1 Basic Rate 1 Mbps
v1.2 Adaptive Frequency Hopping avoid interference
v2.0 Enhanced Data Rate 2 Mbps / 3 Mbps
v2.1 Sniff Subrating transmit less – reducing interference
v3.0 Enhanced Power Control
802.11 PAL
quickly adapt to changing pathloss
5 GHz
v4.0 Low Energy increased modulation index
v4.1 Piconet Clock Adjustment align piconet timing with interferer
v4.2 LE Data Packet Length Extension longer packets = fewer packets
v5.0 Slot Availability Mask
LE Long Range
LE2 Rate
LE Channel Selection Algorithm #2
align piconet timing with nearby LTE bands
increased coding gain
increased symbol rate
better channel selection algorithm
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Physical Layer chips / second symbol rate modulation coding
BR 1 1 bit / symbol GFSK FEC 2/3 & 1/3
2x EDR 1 2 bits / symbol π/4-DQPSK none
3x EDR 1 3 bits / symbol 8-DPSK none
LE 1 1 bit / symbol GFSK none
2x LE 2 1 bit / symbol GFSK none
LR 500k 1 2 chips / symbol GFSK Viterbi
LR 125k 1 8 chips / symbol GFSKViterbi +
Manchester
Bluetooth Radios
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Find good channels / mask out bad channels
Remap good channels to bad channels
nextHop = (prevHop + hop) % 37if nextHop in badChannels:
usedCh = goodChannels[nextHop % len(goodChannels)]else:
usedCh = nextHop
Adaptive Frequency Hopping
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Find good channels / mask out bad channels
Remap good channels to bad channels
random = PRNG()if random % 37 in badChannels:
usedCh = goodChannels[random % len(goodChannels)]else:
usedCh = random % 37
Channel Selection Algorithm #2
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It is easy to transmit louder ...
+20 dBm allowed by Bluetooth spec
but not allowed in all regulatory environments
Receiver sensitivity can be increased ...
but increases power used
Coding gain can be increased ...
manchester coding / viterbi coding
How do you increase range?
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Alternative to “more power”...
Mesh network through multiple nodes
each node is closer to neighbours
reducing “wall” / “pathloss” issues
Must be:
self-organising
self-healing
secure
Mesh
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Physically insecure devices
does this have the same
“network key” as the door lock?
if I ‘hack’ this door bell, can I get
into your home?
Security Implications
Malthing
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Interference will happen
microwave ovens should not take down the house network
Increasing power / sensitivity / coding gain can help
but may not be best solution
Reducing interference may be better approach
more devices / mesh networking / adaptive frequency hopping
Poor security implementation may be the biggest risk
Conclusion
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