Jan 2011 doc IEEE 802 11 110035 r

Jan. 2011 doc. : IEEE 802. 11 -11/0035 r 0 Coverage extetion for IEEE 802. 11 ah Date: 2011 -01 -12 Authors: Submission Slide 1 Heejung Yu, ETRI

Jan. 2011 doc. : IEEE 802. 11 -11/0035 r 0 Abstract In this submission, ETRI’s technical proposals IEEE 802. 11 ah are included. The permuted OFDM symbol prepetition technique has been introduced to extend the coverage based on IEEE 802. 11 OFDM PHY. For narrower bandwidth, the clock downing has been also proposed. Submission Slide 2 Heejung Yu, ETRI

Jan. 2011 doc. : IEEE 802. 11 -11/0035 r 0 Main objectives (1) • The main application of IEEE 802. 11 ah is sensor network, e. g. smart metering. – The measure information at each node should be delivered to a fusion center like an access point. • Among 3 C (Capacity, Cost, Coverage), Cost and Coverage are more significant than Capacity for this application. • To extend coverage with low complexity and low power, we propose a permuted OFDM symbol repetition scheme under the framework of IEEE 802. 11. • For lower bandwidith, clock-dowing is used. Submission Slide 3 Heejung Yu, ETRI

Jan. 2011 doc. : IEEE 802. 11 -11/0035 r 0 Main objectives (2) • TX range of IEEE 802. 11 g at 2. 4 GHz : 100 m (typical) • Carrier shifting from 2. 4 GHz to sub 1 GHz : (2 x ~2. 5 x) 200 ~ 250 m • TX power cannot be increased due to power consumption and power amp. cost at sensor nodes. • Rx sensitivity should be improved to achieve 1 km range. • MIMO 11 n for 11 ah: too expensive for sensor network • Simple solution : repetition (power gain + diversity gain) Submission Slide 4 Heejung Yu, ETRI

Jan. 2011 doc. : IEEE 802. 11 -11/0035 r 0 Main features of ETRI proposal • From baseline of IEEE 802. 11 a/g OFDM PHY, – Bandwidth reduction by downing clock speed • 20 MHz (1 x), 10 MHz(1/2 x), 5 MHz(1/4 x), 2. 5 MHz(1/8 x) – Permuted OFDM symbol repetition • 2 x repetition (similar with frequency spreading in 802. 15. 4 g) – OFDM symbol repetition with subcarrier permutation. • 4 x repetition (extension of 2 x repetition) – Efficient frame structure to support repeated transmission. (Details are included in the draft text in MARCH sumbission) • SIGNAL bit allocation • Auto-detection of repeated frame. Submission Slide 5 Heejung Yu, ETRI

Jan. 2011 doc. : IEEE 802. 11 -11/0035 r 0 Downing clock frequency • By reducing the clock frequency, we can simply obtain lower bandwidth PHY. • Change of timing parameters 1 x 1/2 x 1/4 x 1/8 x Bandwidth 20 MHz 10 MHz 5 MHz 2. 5 MHz Subcarrier spacing 312. 5 k. Hz 156. 25 k. Hz 78. 125 k. Hz 39. 0625 k. Hz OFDM symbol duration 4 s 8 s 16 s 32 s GI duration 0. 8 s 1. 6 s 3. 2 s 6. 4 s IFFT/FFT period 3. 2 s 6. 4 s 12. 8 s 25. 6 s Submission Slide 6 Heejung Yu, ETRI

Jan. 2011 doc. : IEEE 802. 11 -11/0035 r 0 Repetition (1) • 2 x repetition Permuted repetition – This can obtain 3 d. B power gain, frequency diversity gain. • 4 x repetition : with the similar manner Submission Slide 7 Heejung Yu, ETRI

Jan. 2011 doc. : IEEE 802. 11 -11/0035 r 0 Data Rate with 1/8 BW and repetition No repetition 2 x repetition 4 x repetition Mapping Code rate RATE (bps) Mapping Code rate RATE BPSK 1/2 750 kbps BPSK 1/2 375 kbps BPSK 1/2 187. 5 kbps BPSK 3/4 1. 125 Mbps BPSK 3/4 562. 5 kbps BPSK 3/4 281. 25 kbps QPSK 1/2 1. 5 Mbps QPSK 1/2 750 kbps QPSK 1/2 375 kbps QPSK 3/4 2. 25 Mbps QPSK 3/4 1. 125 Mbps QPSK 3/4 562. 5 kbps 16 QAM 1/2 3 Mbps 16 QAM 1/2 1. 5 Mbps 16 QAM 1/2 750 kbps 16 QAM 3/4 4. 5 Mbps 16 QAM 3/4 2. 25 Mbps 16 QAM 3/4 1. 125 Mbps 64 QAM 2/3 6 Mbps 64 QAM 2/3 3 Mbps 64 QAM 2/3 1. 5 Mbps 64 QAM 3/4 6. 75 Mbps 64 QAM 3/4 3. 375 Mbps 64 QAM 3/4 1. 6875 Mbps Submission Slide 8 Heejung Yu, ETRI

Jan. 2011 doc. : IEEE 802. 11 -11/0035 r 0 Requirement and Stisfaction • With Clock-downing and OFDM symbol repetition, we can satisfy the following requirements – Upto 1 km coverage – At least 100 kbps – Simple solution based on IEEE 802. 11 a/g OFDM PHY with signle antenna Submission Slide 9 Heejung Yu, ETRI

Jan. 2011 doc. : IEEE 802. 11 -11/0035 r 0 Conclusion • To satisfy requirements fo 802. 11 ah, BANDWIDTH REDUCTION and OFDM SYMBOL REPETITION schems should be included. • In ETRI proposal, we proposed – Downing sampling clock – Permuted OFDM symbol repetition – Efficient frame structure including SIGNAL field based on 802. 11 a/g OFDM PHY. • These are a minor modification of OFDM PHY. Fast time-to-market is possible. Submission Slide 10 Heejung Yu, ETRI