UWB-TSCH : Time and Frequency Division Multiplexing for Ultra-wideband Communications Maximilien Charlier University of Mons, Belgium June 4, 2019 CORES 2019
UWB UWB-TSCH Test & Validation Conclusion Table of contents 1 Introduction to Ultra Wideband 2 UWB Time Slotted Channel Hopping (UWB-TSCH) Time slot Channel Hopping 3 Test & Validation 4 Conclusion Maximilien Charlier Challenges in Using TSCH with UWB CommunicationsJune 4, 2019 2/26
UWB UWB-TSCH Test & Validation Conclusion Table of contents 1 Introduction to Ultra Wideband 2 UWB Time Slotted Channel Hopping (UWB-TSCH) Time slot Channel Hopping 3 Test & Validation 4 Conclusion Maximilien Charlier Challenges in Using TSCH with UWB CommunicationsJune 4, 2019 3/26
UWB UWB-TSCH Test & Validation Conclusion Ultra Wideband Wireless communication technology Pulse radio Frequency band ≥ 500 MHz Very short pulse ( < ns) ⇒ Wide frequency band Figure: Pulse waveform Source: wlan62d [2] Maximilien Charlier Challenges in Using TSCH with UWB CommunicationsJune 4, 2019 4/26
UWB UWB-TSCH Test & Validation Conclusion Ultra Wideband Low power spectral density The power is spread over the whole UWB spectrum, therefore, the power density is much lower than narrow band technology. Maximilien Charlier Challenges in Using TSCH with UWB CommunicationsJune 4, 2019 5/26
UWB UWB-TSCH Test & Validation Conclusion Medium Access Control 1 Transmit as soon as possible ALOHA Low channel occupancy Low power efficiency (overhearing) Maximilien Charlier Challenges in Using TSCH with UWB CommunicationsJune 4, 2019 6/26
UWB UWB-TSCH Test & Validation Conclusion Medium Access Control 1 Transmit as soon as possible ALOHA Low channel occupancy Low power efficiency (overhearing) 2 Listen before transmit Carrier-Sense Multiple Access (CSMA) Reduce collision No Clear Channel Assessment in UWB (PSD too low) Maximilien Charlier Challenges in Using TSCH with UWB CommunicationsJune 4, 2019 6/26
UWB UWB-TSCH Test & Validation Conclusion Medium Access Control 1 Transmit as soon as possible ALOHA Low channel occupancy Low power efficiency (overhearing) 2 Listen before transmit Carrier-Sense Multiple Access (CSMA) Reduce collision No Clear Channel Assessment in UWB (PSD too low) 3 Transmit according a scheduling Time Division Multiple Access (TDMA) Channel occupancy improvement Minimization of the power consumption Maximilien Charlier Challenges in Using TSCH with UWB CommunicationsJune 4, 2019 6/26
UWB UWB-TSCH Test & Validation Conclusion Medium Access Control 1 Transmit as soon as possible ALOHA Low channel occupancy Low power efficiency (overhearing) 2 Listen before transmit Carrier-Sense Multiple Access (CSMA) Reduce collision No Clear Channel Assessment in UWB (PSD too low) 3 Transmit according a scheduling Time Division Multiple Access (TDMA) Channel occupancy improvement Minimization of the power consumption Our proposal: ⇒ Increase of channel occupancy by adapting TSCH to UWB. Maximilien Charlier Challenges in Using TSCH with UWB CommunicationsJune 4, 2019 6/26
UWB UWB-TSCH Test & Validation Conclusion Table of contents 1 Introduction to Ultra Wideband 2 UWB Time Slotted Channel Hopping (UWB-TSCH) Time slot Channel Hopping 3 Test & Validation 4 Conclusion Maximilien Charlier Challenges in Using TSCH with UWB CommunicationsJune 4, 2019 7/26
UWB UWB-TSCH Test & Validation Conclusion Time Slotted Channel Hopping TSCH is a 802.15.4 MAC protocol originally for Narrow Band. Time Domain/TDMA ( T ime S lotted) Challenge: new PHY parameters (preamble, bit-rate) Frequency Domain ( C hannel H opping) Narrow band: improvement of the resilience to interference UWB: maximizing the bandwidth (with concurrent communications) Challenge: concurrent communication, channel agility Maximilien Charlier Challenges in Using TSCH with UWB CommunicationsJune 4, 2019 8/26
UWB UWB-TSCH Test & Validation Conclusion TSCH - Time slot Maximilien Charlier Challenges in Using TSCH with UWB CommunicationsJune 4, 2019 9/26
UWB UWB-TSCH Test & Validation Conclusion TSCH - Time slot Maximilien Charlier Challenges in Using TSCH with UWB CommunicationsJune 4, 2019 9/26
UWB UWB-TSCH Test & Validation Conclusion TSCH - Time slot Clock drift ⇒ Guard time RX Guard : clock drift & clock granularity Maximilien Charlier Challenges in Using TSCH with UWB CommunicationsJune 4, 2019 9/26
UWB UWB-TSCH Test & Validation Conclusion TSCH - Time slot Clock drift ⇒ Guard time RX Guard : clock drift & clock granularity Maximilien Charlier Challenges in Using TSCH with UWB CommunicationsJune 4, 2019 9/26
UWB UWB-TSCH Test & Validation Conclusion TSCH - Time slot Clock drift ⇒ Guard time RX Guard : clock drift & clock granularity Maximilien Charlier Challenges in Using TSCH with UWB CommunicationsJune 4, 2019 9/26
UWB UWB-TSCH Test & Validation Conclusion TSCH - Time slot Clock drift ⇒ Guard time RX Guard : clock drift & clock granularity Ack Guard : clock granularity Maximilien Charlier Challenges in Using TSCH with UWB CommunicationsJune 4, 2019 9/26
UWB UWB-TSCH Test & Validation Conclusion Scheduling Transmissions to each neighbour scheduled locally within a slotframe. TimeSlot Number (TSN) 0 1 2 3 5 (Freq. domain) Channel Offset 4 A → B 3 2 1 0 Example of slotframe Maximilien Charlier Challenges in Using TSCH with UWB Communications June 4, 2019 10/26
UWB UWB-TSCH Test & Validation Conclusion Scheduling Transmissions to each neighbour scheduled locally within a slotframe. TimeSlot Number (TSN) 0 1 2 3 0 5 (Freq. domain) Channel Offset 4 A → B 3 2 1 0 0 1 2 3 4 Absolute Slot Number (ASN) - (Time domain) Example of slotframe Maximilien Charlier Challenges in Using TSCH with UWB Communications June 4, 2019 10/26
UWB UWB-TSCH Test & Validation Conclusion Scheduling Transmissions to each neighbour scheduled locally within a slotframe. TimeSlot Number (TSN) 0 1 2 3 0 5 B → A (Freq. domain) Channel Offset 4 A → B 3 2 B → D 1 0 0 1 2 3 4 Absolute Slot Number (ASN) - (Time domain) Example of slotframe Maximilien Charlier Challenges in Using TSCH with UWB Communications June 4, 2019 10/26
UWB UWB-TSCH Test & Validation Conclusion Scheduling Transmissions to each neighbour scheduled locally within a slotframe. TimeSlot Number (TSN) 0 1 2 3 0 5 B → A (Freq. domain) Channel Offset 4 A → B 3 2 B → D 1 D → C 0 A → C 0 1 2 3 4 Absolute Slot Number (ASN) - (Time domain) Example of scheduling Maximilien Charlier Challenges in Using TSCH with UWB Communications June 4, 2019 10/26
UWB UWB-TSCH Test & Validation Conclusion Channel Hopping IEEE 802.15.4 defines 16 channels for the UWB PHY ranging from 249.6 MHz up to 10.16 GHz. 7 Channel Index 5 4 3 2 1 3494 3994 3994 4493 6490 6490 Frequency (MHz) Subset of the UWB channels defined by IEEE 802.15.4 [3] suported by Decawave transceiver. Maximilien Charlier Challenges in Using TSCH with UWB Communications June 4, 2019 11/26
UWB UWB-TSCH Test & Validation Conclusion Channel Hopping Channel 2 overlaps with channel 1 and 3. Channel 1 Channel 2 Channel 3 Power Spectral Density (dBm) 0 − 10 − 18 3245 3494 3744 3744 3994 4243 4243 4493 4742 Frequency (MHz) Transmit PSD mask of UWB Channel 1-3 [3]. Maximilien Charlier Challenges in Using TSCH with UWB Communications June 4, 2019 12/26
UWB UWB-TSCH Test & Validation Conclusion Channel Hopping 3 possible simultaneous communications based on 3 separate channels. 7 Channel Index 5 4 3 2 1 3494 3994 3994 4493 6490 6490 Frequency (MHz) Subset of the UWB channels defined by IEEE 802.15.4 [3] suported by Decawave transceiver. Maximilien Charlier Challenges in Using TSCH with UWB Communications June 4, 2019 13/26
UWB UWB-TSCH Test & Validation Conclusion Channel Hopping The Pulse Repetition Frequencies (PRF) parameter allows concurrent communication on the same physical channel. Ch.1, PRF 16 MHz Channel 1 Ch.1, PRF 64 MHz Maximilien Charlier Challenges in Using TSCH with UWB Communications June 4, 2019 14/26
UWB UWB-TSCH Test & Validation Conclusion Channel Hopping 6 possibles simultaneous communications based on 3 separate channels and 2 P ulse R epetition F requencies (PRF). 7 Channel Index 5 4 3 2 1 3494 3994 3994 4493 6490 6490 Frequency (MHz) Subset of the UWB channels defined by IEEE 802.15.4 [3] suported by Decawave transceiver. Maximilien Charlier Challenges in Using TSCH with UWB Communications June 4, 2019 15/26
UWB UWB-TSCH Test & Validation Conclusion Table of contents 1 Introduction to Ultra Wideband 2 UWB Time Slotted Channel Hopping (UWB-TSCH) Time slot Channel Hopping 3 Test & Validation 4 Conclusion Maximilien Charlier Challenges in Using TSCH with UWB Communications June 4, 2019 16/26
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