March 2002 doc IEEE 802 15 02138 r

March 2002 doc. : IEEE 802. 15 -02/138 r 0 Tutorial on 802. 15. 2 Draft Steve Shellhammer, Nada Golmie, Robert Van Dyck, Jie Liang, Y. C. Maa, Anuj Batra, Jim Lansford, and Arunachalam Submission 1 Steve Shellhammer, Symbol Technologies

March 2002 doc. : IEEE 802. 15 -02/138 r 0 Outline of 802. 15. 2 Draft • Interference Modeling – Physical Layer Modeling – MAC Layer Modeling • Collaborative Coexistence Mechanisms – AWMA – PTA • Noncollaborative Coexistence Mechanisms – BT Packet Scheduling and Selection – BT Adaptive Frequency Hopping Submission 2 Steve Shellhammer, Symbol Technologies

March 2002 doc. : IEEE 802. 15 -02/138 r 0 System Simulation Modeling Submission 3 Steve Shellhammer, Symbol Technologies

March 2002 doc. : IEEE 802. 15 -02/138 r 0 Channel Modeling • Additive White Gaussian Noise • Path loss model • Received power and SIR depend on topology and device parameters: Submission 4 Steve Shellhammer, Symbol Technologies

March 2002 doc. : IEEE 802. 15 -02/138 r 0 Physical Layer Modeling • DSP based implementation of transceivers • Design using typical parameters (goal is to remain non-implementation specific) • Bluetooth – Non-coherent Limiter Discriminator receiver • IEEE 802. 11 – Direct Sequence Spread Spectrum (1 & 2 Mbits/s) – Complementary Code Keying (5. 5 & 11 Mbits/s) – Frequency Hopping (1 Mbits/s) Submission 5 Steve Shellhammer, Symbol Technologies

March 2002 doc. : IEEE 802. 15 -02/138 r 0 MAC Layer Modeling • MAC behavioral implementation for Bluetooth and IEEE 802. 11 (connection mode) • Frequency hopping • Error detection and correction – Different error correction schemes applied to packet segments (Bluetooth) – FCS (802. 11) • Performance statistics collection – Access delay, packet loss, residual error, throughput Submission 6 Steve Shellhammer, Symbol Technologies

March 2002 doc. : IEEE 802. 15 -02/138 r 0 Typical Modeling Results Percentage of Packet Loss BT BT 802. 11 Type Traffic 1 Mbit/s DS 1 Mbit/s FH Submission Voice 12 90 Data 38 14 Voice 12 44 Data 18 15 Voice 2. 5 58 Data 13 2. 3 7 802. 11 AP 802. 11 Mobile d=1 m Bluetooth Slave Bluetooth Master Bluetooth Data Packets. DM 5, 2871 bits Offered Load 50% SCO Packets HV 1, 366 bits Tx Power 1 m. W 802. 11 Data Rate Modes Packet Size 12000 bits Offered Load 50% Tx Power 11 Mbits/s, 1 Mbits/s Direct Sequence, FH 25 m. W Steve Shellhammer, Symbol Technologies

March 2002 doc. : IEEE 802. 15 -02/138 r 0 Collaborative Coexistence Mechanisms Submission 8 Steve Shellhammer, Symbol Technologies

March 2002 doc. : IEEE 802. 15 -02/138 r 0 Alternating Wireless Medium Access (AWMA) • Collaborate Coexistence Mechanism for Collocated IEEE 802. 11 b and Bluetooth – Both in the same laptop or handheld • Coordinated MAC Layer • Subdivide WLAN Beacon Interval – WLAN Interval – WPAN Interval Submission 9 Steve Shellhammer, Symbol Technologies

March 2002 doc. : IEEE 802. 15 -02/138 r 0 Alternating Wireless Medium Access • Synchronization of all units connected to the same WLAN Access Point • Eliminates WLAN/WPAN interference due to no temporal overlap • Good for high-density of WLAN/WPAN units. • Does not support Bluetooth SCO link Submission 10 Steve Shellhammer, Symbol Technologies

March 2002 doc. : IEEE 802. 15 -02/138 r 0 Packet Traffic Arbitration PTABluetooth Interface Bluetooth Baseband (up to HCI) Bluetooth Radio Submission BT Traffic 802. 11 traffic PTA-802. 11 Interface 802. 11 b MAC 802. 11 b PHY This proposal does not address PHY or antenna issues 11 Steve Shellhammer, Symbol Technologies

March 2002 doc. : IEEE 802. 15 -02/138 r 0 Packet Traffic Arbitration • Collaborative techniques define rules in advance for traffic management by direct communication between systems…no learning • Traffic light (TDMA) totally prevents collisions • Yield, 4 -way stop, etc. are also valid rules • Maximizes traffic while avoiding collisions Submission 12 Steve Shellhammer, Symbol Technologies

March 2002 doc. : IEEE 802. 15 -02/138 r 0 Packet Traffic Arbitration • Dynamic algorithm schedules traffic • Knowledge of time-frequency collisions is key – Simultaneous transmission or reception allowed – Tx simultaneous with Rx allowed if not in-band (requires good LNA and REALLY good channel filters) – Critical for SCO operation-WLAN can work around in-band collisions • This figure does not show polls/nulls, which often dominates Bluetooth traffic Submission 13 Steve Shellhammer, Symbol Technologies

March 2002 doc. : IEEE 802. 15 -02/138 r 0 Packet Traffic Arbitration • Assumed MAC structure – At most one message pending for BT – At most two messages pending for WLAN FIFO 2 Enable WLAN Modem WLAN FIFO 1 WLAN Stack Frequency Collision Map Tx Event Decision Logic Backoff & CCA PTA Engine Bluetooth Stack Switch Matrix Decision Logic WLAN Modem Bluetooth FIFO Enable Submission 14 Steve Shellhammer, Symbol Technologies

March 2002 doc. : IEEE 802. 15 -02/138 r 0 Adaptive Packet Selection • Bluetooth provides a wide range of packet types to select from: payload length, FEC options • DM 1, DM 3, DM 5, DH 1, DH 3, DH 5, AUX 1 – Guidelines: – range limited situation: use DM packet for its FEC – interference • Adaptive packet payload length selection: – Adaptive fragmentation Submission 15 Steve Shellhammer, Symbol Technologies

March 2002 doc. : IEEE 802. 15 -02/138 r 0 Adaptive Packet Scheduling • Interference Estimation • Maintain a Frequency Usage Table at master and slave nodes. • Slave updates master’s Frequency Usage Table every update interval. • Master Scheduling Policy • Use “good” frequencies for master / slave transmission (upstream and downstream) Submission 16 Steve Shellhammer, Symbol Technologies

March 2002 doc. : IEEE 802. 15 -02/138 r 0 Channel Classification • Draft provides an example algorithm for determining the quality of the channels. Actual implementation is left to the vendor. • Metrics that could be used by the vendors include: – RSSI, PER, Carrier Sensing, and Packet ACK. • Measurements can be made using: – Batch (block) techniques. – Online or offline techniques. Submission 17 Steve Shellhammer, Symbol Technologies

March 2002 doc. : IEEE 802. 15 -02/138 r 0 Adaptive Packet Scheduling Advantages: • It does not require changes to the Bluetooth specifications. • It conforms to FCC rules. • It saves power since no transmission is wasted in bad channels • It is neighbor-friendly and mitigates interference on other systems. Submission 18 Steve Shellhammer, Symbol Technologies

March 2002 doc. : IEEE 802. 15 -02/138 r 0 Adaptive Packet Scheduling Submission 19 Steve Shellhammer, Symbol Technologies

March 2002 doc. : IEEE 802. 15 -02/138 r 0 Simulation Results • Bluetooth Performance BT Slave Pr [ Packet Loss] 0. 25 BT Slave Mean Access Delay (seconds) 0. 008 0. 2 No Scheduling, DM 3 Scheduling, DM 5 No Scheduling, DM 5 0. 15 No Scheduling, DM 3 0. 004 No Scheduling, DM 1 0. 1 Scheduling, DM 1 0. 002 0. 05 0 No Scheduling, DM 5 0. 006 Scheduling, DM 1, DM 3, DM 5 0 1 2 3 4 No Scheduling, DM 1 0 5 Distance between Bluetooth Slave and 802. 11 Mobile (meters) Submission 0 1 2 3 4 5 Distance between Bluetooth Slave and 802. 11 Mobile (meters) 20 Steve Shellhammer, Symbol Technologies

March 2002 doc. : IEEE 802. 15 -02/138 r 0 Simulation Results • IEEE 802. 11 Performance 802. 11 Mobile Pr [ Packet Loss] 0. 05 No Scheduling, DM 1 0. 04 No Scheduling, DM 3 0. 03 No Scheduling, DM 5 0. 02 Scheduling, DM 1, DM 3, DM 5 0. 01 0 0 1 2 3 4 5 Distance between Bluetooth Slave and 802. 11 Mobile (meters) Submission 21 Steve Shellhammer, Symbol Technologies

March 2002 doc. : IEEE 802. 15 -02/138 r 0 Adaptive Frequency Hopping • Adaptive frequency hopping (AFH) is a noncollaborative mechanism that enables the coexistence of IEEE 802. 15. 1 devices with frequency static devices in the 2. 4 GHz ISM band such as IEEE 802. 11 b. • This mechanism dynamically changes the frequency hopping sequence in order to avoid or mitigate the interference seen by both 802. 11 b and the 802. 15. 1 device. Submission 22 Steve Shellhammer, Symbol Technologies

March 2002 doc. : IEEE 802. 15 -02/138 r 0 Adaptive Frequency Hopping • There are 4 main elements of Adaptive Hopping: – – AFH Capability Discovery Channel Classification Channel Quality Information Exchange Adaptive Hopping Mechanism • Channel classification is a mechanism for determining the quality of a channel. The channel is classified as either good or bad based on predefined metrics. – Used by both AFH and packet scheduling. Submission 23 Steve Shellhammer, Symbol Technologies

March 2002 doc. : IEEE 802. 15 -02/138 r 0 Adaptive Frequency Hopping Submission 24 Steve Shellhammer, Symbol Technologies

March 2002 doc. : IEEE 802. 15 -02/138 r 0 Adaptive Frequency Hopping • The legacy hop kernel generates the hopping sequence defined in the IEEE 802. 15. 1 standard. This hopping sequence is referred to as the original hopping sequence. Submission 25 Steve Shellhammer, Symbol Technologies

March 2002 doc. : IEEE 802. 15 -02/138 r 0 Adaptive Frequency Hopping • Partition sequence generator imposes a structure on the original hopping sequence without changing pseudo-random properties. – For SCO+ACL, good slots are first assigned to voice slots. – For ACL only, good and bad channels are grouped together. Reduces the effects of transitions from good-to-bad channels (retransmissions) and badto-good channels (idle slots). Maximizes throughput. Submission 26 Steve Shellhammer, Symbol Technologies

March 2002 doc. : IEEE 802. 15 -02/138 r 0 Adaptive Frequency Hopping • The frequency re-mapping function uses the partition sequence to generate the new hopping sequence. If necessary, this block uniformly re-maps the original hopping channel onto the set defined by the partition sequence. – When p(k) = 1, the re-mapping function only hops over the good channels (reduced frequency hopping). Submission 27 Steve Shellhammer, Symbol Technologies

March 2002 doc. : IEEE 802. 15 -02/138 r 0 LMP Commands • The following LMP commands are needed for the AFH mechanism: Description LMP Command LMP_features_req/res Identifies AFH-capable devices LMP_channel_metrics_req/res Request and Return of Slave’s Classification LMP_AFH_start Forces device to start adaptive hopping LMP_regular_hopping_req Forces device back to regular hopping set LMP_AFH_check_req/res Check to ensure that device is using the correct hopping sequence Submission 28 Steve Shellhammer, Symbol Technologies

March 2002 doc. : IEEE 802. 15 -02/138 r 0 Summary • Draft D 05 will be available on the server by Thursday AM. • Motion to go to letter ballot on 802. 11 and 802. 15 on Friday AM. • 40 day letter ballot to start no later than March 22, 2002. Submission 29 Steve Shellhammer, Symbol Technologies