Project: IEEE Coexistence Study Group Submission Title: [Coexistence Among the PHYs]

1. Project: IEEE Coexistence Study Group Submission Title: [Coexistence Among the PHYs] Date Submitted: [The date the document is contributed, in the format “21 May, 1999”] Source: [Robert Poor] Company [Ember Corporation] Address [313 Congress Street / Boston, MA 02210 / USA] Voice:[617 951-0200], FAX: [617 951-0999], E-Mail:[rpoor@ieee.org] Re: [] Abstract: [This document proposes PHY Coexistence Characterization (PCC), a simple model designed to quantify coexistence at the PHY level among wireless devices covered under IEEE standards. While PCC is arguably simplistic, it is straightforward to compute, produces easily interpreted results and is certifiably conservative: higher layer mechanisms will only serve to enhance coexistence. This document describes PCC and how it is computed.] Purpose: [This document is intended to encourage discussion, refining and consensus of PHY Coexistence Characterization.] Notice: This document has been prepared to assist the IEEE P802.15. It is offered as a basis for discussion and is not binding on the contributing individual(s) or organization(s). The material in this document is subject to change in form and content after further study. The contributor(s) reserve(s) the right to add, amend or withdraw material contained herein. Release: The contributor acknowledges and accepts that this contribution becomes the property of IEEE and may be made publicly available by IEEE 802. Robert Poor, Ember Corporation

2. Coexistence Among the PHYs PHY Coexistence Characterization (PCC) among 802.11 and 802.15 devices Robert Poor, Ember Corporation

3. Goals We wish to: • Anticipate coexistence issues among specific 802.11 and 802.15 devices • Quantifiably characterize coexistence through simulation, independent of application • Specify straightforward simulation models that (nearly) everyone can agree on. Robert Poor, Ember Corporation

4. Approach • Model interactions at the PHY level only. • Limit study to 802.11b, 802.15.1, 802.15.3, 802.15.4 devices operating at 2.4GHz (this may be broadened as appropriate). • Characterized by the investigator: nominal transmit power, acceptable error rate. • Characterized by the spec: everything else. • Err on the conservative side. Robert Poor, Ember Corporation

5. dTR PHY Coexistence Characterization:The Model Receiver (Std A) Transmitter (Std A) SIGNAL PT = PNOM PTR = S+6db Step 1: Assume that the transmitter’s signal is received 6dB above Std A’s published receiver sensitivity. (If desired, calculate the distance between transmitter and receiver for a given transmit power, but this is optional.) Robert Poor, Ember Corporation

6. PHY Coexistence Characterization:The Model Receiver (Std A) Interferer (Std B) Transmitter (Std A) SIGNAL PT = PNOM PTR = S+6db INTERFERENCE PIR | Err = x Step 2: Compute the received interference power PIR that results in a specified error rate of the transmitted signal. Robert Poor, Ember Corporation

7. dPCC PHY Coexistence Characterization:The Model Receiver (Std A) Interferer (Std B) Transmitter (Std A) SIGNAL PT = PNOM PTR = S+6db INTERFERENCE PIR | Err = x PI = PNOM Step 3: Use PIR and PI to calculate the minimum coexisting distance dPCC between the interferer and the receiver. Path loss model will be adopted as per IEEE 802.15.2 recommendations. Robert Poor, Ember Corporation

8. PHY Coexistence Characterization:The Model DPCC = F( fTRANS , fINTER ) Step 4: Repeat the previous steps for all combinations of transmitter channel and interferer channel. The resulting set of coexisting distances forms the PCC for the two coexisting devices. Robert Poor, Ember Corporation

9. PCC not grounded in reality PCC is pessimistic: • Principal defense: many devices avoid congestion through alternate channels. • Spread spectrum reduces interference. • MAC tries to be fair in usage within a channel. • Few applications run at 100% duty cycle Robert Poor, Ember Corporation

10. Wrapping Up • Any obvious holes? • TG4 wishes to use PCC to characterize coexistence. Any other takers? • Is there desire to formalize PCC? • Who can help run the simulations? Robert Poor, Ember Corporation