AN2935 CH370 - Datasheet Archive

 

Application Note Document Number: AN2935 Rev. 1.2, 07/2005 MC1319x Coexistence By: R. Rodriguez 1 Introduction The MC1319x device

 

Freescale Semiconductor Application Note Document Number: AN2935 AN2935 Rev. 1.2, 07/2005 MC1319x Coexistence By: R. Rodriguez 1 Introduction The MC1319x device is a ZigBee and IEEE® 802.15.4 Standard compliant transceiver meant to operate in the 2.4GHz Industry, Scientific and Medical (ISM) unlicensed band. This application note will address the mitigating strategies and characteristics of the MC1319x transceiver in the presence of the following interferers found in the ISM band: · 802.15.4 ZigBee · 802.11b/g Wireless Local Area Network (WLAN) · 802.15 BlueTooth Wireless Personal Area Network (WPAN). The MC1319x was characterized through both lab and radiated field testing to determine its ability to coexist in the presence of interferers located in the ISM band. Several factors affect the coexistence performance of the MC1319x. The distance of the desired receiver to the desired transmitter and the distance of the interfering transmitter to the desired receiver both determine the channel environment. Other channel conditions include © Freescale Semiconductor, Inc., 2005. All rights reserved. Contents 1 2 3 4 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . 1 Interference Rejection Characteristics . . . . . 2 Channel Conditions . . . . . . . . . . . . . . . . . . . 17 Mitigating Strategies . . . . . . . . . . . . . . . . . . 19 path loss, multi-path, fading, and polarization loss. The transmission characteristics of the devices such as carrier frequencies, channel bandwidth, transmitter duty cycle, and transmitter output power also contribute to the overall coexistence performance. The transmitter output power of the MC1319x for all measurements and recommendations contained are based upon 0dBm (nominal). In actuality, the transceiver output power is programmable up to 4dBm. The detailed performance of the transceiver is found in the MC1319x data sheets and reference manuals. Throughout this application note, the degree to which interferers will impact the receiver is quantified by interference rejection measurements. The test procedure for these measurements is outlined and explained in the following section. The interference rejection measurements quantify the receiver immunity to interference. The greater the interference rejection, the better the performance of the receiver in the presence of interferers. In general, a greater frequency offset from the desired carrier results in better interference rejection. 2 2.1 Interference Rejection Characteristics Test Methodology The transmitter of the desired carrier and the transmitter of the interferer were calibrated to a known power level at the receiver. The desired carrier was permanently set to -82dBm at the input of the receiver; the interferer was decreased from a power level of -10dBm until the packet error rate was 25MHz and 25MHz and