ZigBee Propagation Testing

Transcription

1 ZigBee Propagation Testing EDF Energy Ember December 3 rd 2010

2 Contents 1. Introduction Purpose Test Plan Location Test Point Selection Equipment Results Overview Breakdown by Location Conclusions and Recommendations Intervening Walls Antenna Selection Range Extenders Meter Placement A1. Glossary A2. Raw Data... 12

3 1. Introduction 1.1 Purpose This report describes a series of tests performed at a location where EDF are currently considering installing ZigBee based smart metering infrastructure in an apartment block. Initially there would be an electricity meter position for each floor where all meters for the floor will be located. Each meter would be required to communicate with an In Home Display (IHD) in the relevant apartment. The trial was commissioned in order to determine whether the radio propagation characteristics of ZigBee are likely to provide adequate coverage over a single floor of the apartment complex. 1.2 Principles and Objectives The fundamental restriction on radio coverage within a building is imposed by the basic link budget. This in turn is determined by a range of factors, the most important being transmit power and receiver sensitivity. The transmit power itself is limited in Europe by the harmonised European standard set by ETSI 1. Practically this limits transmitters to +10dBm (10mW), but in the case of this trial +8dBm (6.3mW) was used as this is the maximum power of the em357 chip obtainable without external amplification. For any given modulation scheme the receive sensitivity depends primarily on the noise level in the receiver, but this can vary between different hardware depending on the specifics of the implementation. The Ember em357 has a sensitivity of around -102dBm, giving a total link budget for these tests of 110dB. Using a simplified form of the Friis transmission equation it is easy to use this link budget to calculate the maximum free space propagation distance possible with this test setup: Assuming unity gain of the antennas and ignoring losses in the RF front ends: Plugging the relevant numbers into this equation gives a maximum range of over 3km. While in practice this will not be achievable, it does indicate that in an indoor environment the free space loss will not be the most important factor in determining how far the signal can propagate. In these situations, losses through obstructions and weak signal spots due to interference from multipath signals will dominate. 1 ETSI EN section Page 3

4 2. Test Plan 2.1 Location The section selected was complete with doors fitted on all 6 apartments and on the riser cupboard. It also represented a worst case scenario as it had the longest potential propagation distance between the meter enclosure and the apartments. 2.2 Test Point Selection 24 Locations were selected across one floor of the block. Each apartment is sub-divided in to several rooms and at least one test point was chosen for each one. The test points were also generally chosen to be close to the outer wall, in order to maximise the distance to the riser and therefore present the worst case propagation scenario for each data point. The selected test locations are numbered in figure 2.2 below. The meter location is in the riser cupboard at the centre and is marked with the letter M. Figure 2.2 Test Location Map Page 4

5 2.3 Equipment As the meters and in home displays (IHDs) were not yet available at the time of the test, the propagation trials were conducted using Ember ZigBee development hardware. This consisted of a Telegesis Radio Module 2 designed around the Ember EM357 3 System-on-Chip (SoC). This radio module was mounted on a standard Ember Development breakout board 4. The complete hardware assembly is picture in figure 2.3. Antenna USB Connector Radio Module Figure 2.3 Test Hardware The first unit ( node ), designated the sensor node was programmed to simply transmit unsolicited packets periodically. This node represented the In Home Display, and was placed in each of the test locations sequentially. The second of these units was designated the sink node, and was programmed to remain in receive mode and report the signal strength and link quality statistics for all received packets. A laptop computer was connected to the sink node in order to capture this data for analysis. This assembly was used as a proxy for the smart meter and therefore remained in the riser cupboard for the duration of the trial. During the entire test the riser cupboard door was closed to more closely match the conditions likely in the final implementation Page 5

6 3. Results 3.1 Overview Overall the results were positive. Very few packets were lost, and the RSSI and LQI statistics were encouraging. A summary of the data collected is shown in table 3.1 below. Locations 24 Packets per Location 10 Total Packets Transmitted 240 Total Packets Received 197 (82%) Mean RSSI (dbm) (~10dB Above Min) Mean LQI 216 Table 3.1 Result Overview Figures 3.1 and 3.2 illustrate the distribution of received RSSI and LQI statistics respectively. The RSSI histogram shows a relatively uniform distribution between around -65 and -90dBm. The LQI statistics however show a clear bias towards ideal link quality (255). This non-linear relationship is displayed more clearly in figure 3.3 at the bottom of the page. The overwhelming majority of packets received with an RSSI greater than -90dBm report an LQI of 255. Page 6

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8 3.2 Breakdown by Location Table 3.2 shows the results listed by location. The data demonstrate that in all but 4 of the test locations good LQI was reported with minimal packet loss. Of the remaining 4, all received at least 20% of the transmitted packets with varying LQI. Location ID Mean RSSI Mean LQI % Packets Received Table 3.2 Result Data by Location Packets Received >=80% Packets Received >= 50% Packets Received < 50% Figure 3.4 RSSI by Location Page 8

9 4. Conclusions and Recommendations 4.1 Intervening Walls As figure 3.4 makes clear, the quality of the radio link is not simply a function of distance between the transmitting and receiving node. Clearly the number and nature of the intervening obstructions plays a part. For example, test location 24 is relatively close to the sink node, but the reported signal strength is amongst the lowest. Inspection of the core G floor plan shows that some of the internal walls are of thick solid concrete construction, while others are just internal dividing walls. The thicker, structural type walls are likely to attenuate the signal to a much larger degree. X - Internal Wall X - Structural Wall Figure 4.1 Location 24 Transmission Path Obstructions With the rough estimate that a structural wall causes three times the signal attenuation of a partition, it is possible to draw a convincing correlation between the number and type of intervening walls and the received RSSI (see figure 3.2). Clearly any large metal surfaces or other obstacles will impact the signal, but this simple observation may still be instructive when considering if a range extender is likely to be necessary, and if so where it should be placed. Page 9

10 4.2 Antenna Selection The Telegesis module used for the trial and described in section 2.3 is designed to be used in a variety of applications, including those with space constraints. For this reason a small and relatively cheap COTS microstrip PIFA has been chosen for the antenna. Since neither the antenna in a meter or IHD used in a real SE deployment will have significant size limitations, it is likely that it will radiate more efficiently than the one used in these tests. A modest improvement can therefore be expected 4.3 Range Extenders As mentioned in section 4.1 a range extender (or repeater ) could be used in any cases where the signal might not otherwise reach the intended destination. By using the mesh networking capability inherent in ZigBee, a device acting only to retransmit incoming packets could be strategically placed between the meter and the remote IHD, thus bridging the radio link. However given the almost universal signal coverage demonstrated by these tests, in the majority of cases such a device is likely to be unnecessary. 4.4 Meter Placement Metal is undoubtedly the material most likely to cause problems for propagation of radio signals. Figure 4.3 shows the significant amount of metal that was present in the riser cupboard during the test. By placing the meter in a location which maximises the distance to the surrounding metal, it should be possible to minimise the angles occluded by these obstructions and therefore maximise signal coverage in the building. Sink Node Figure 4.3 Riser Cabinet Page 10

11 A1. Glossary AMI COTS dbm DSSS IHD ISM LQI Mesh PHY PIFA RSSI SE SoC ZigBee IEEE Standard Specifying PHY and MAC layers for low data rate wireless networks. This is the standard used by ZigBee in the MHz ISM Band. Advanced Metering Infrastructure. Generic term referring to a system which can measure and analyse energy and resource usage. Commercial off the shelf Measured Power in decibels referenced to 1 milliwatt. P(dBm) = 10log(P(mW)) Direct Sequence Spread Spectrum. A technique where the transmitted bit stream is further modulated by a sequence of chips known a priori by the receiver. This sequence can then be correlated with the incoming signal to reconstruct the original bit stream. In Home Display Industrial Scientific and Medical. Unlicensed frequency bands intended for use in the named application areas Link Quality Indicator. Dimensionless metric used to assess the relative quality of radio connections. It scales from 255 to 0 with higher values indicating better links. Calculation is based on errors detected in the DSSS decoding of the received bytes. Maximum LQI indicates an average of zero chip errors present in the byte. If more than 6.25% chip errors are detected, the LQI is reported as zero. Mesh networking is a technology allowing each node on a network to act as an independent router. In this way, a signal can take any path across an arbitrary number of hops to get to its intended recipient. As there may be multiple possible routes the mesh can be self healing, allowing operation to continue when one or more links is lost. Physical Layer. The basic hardware transmission mechanism used to transmit and receive raw data to and from the medium. Planar Inverted-F Antenna Received Signal Strength Indicator. A measure of the peak raw radio power in the receiver during the packet reception. Usually quoted in dbm Smart Energy System-on-Chip. A self contained silicon microcontroller implementing radio and networking functions alongside application level tasks. A specification for a high-level communications protocol based on the standard. The system is designed for low-cost, low-power and secure wireless mesh networking. Page 11

12 A2. Raw Data RX [DATA] from: 000D6F00005C3ED4; len:48, Location:2, Counter:0 [RSSI: -75, LQI: 255] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:2, Counter:1 [RSSI: -72, LQI: 255] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:2, Counter:2 [RSSI: -84, LQI: 255] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:2, Counter:3 [RSSI: -76, LQI: 255] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:2, Counter:4 [RSSI: -73, LQI: 255] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:2, Counter:5 [RSSI: -77, LQI: 255] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:2, Counter:6 [RSSI: -70, LQI: 255] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:2, Counter:7 [RSSI: -76, LQI: 255] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:2, Counter:8 [RSSI: -70, LQI: 255] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:2, Counter:9 [RSSI: -72, LQI: 255] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:3, Counter:1 [RSSI: -73, LQI: 255] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:3, Counter:2 [RSSI: -72, LQI: 255] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:3, Counter:3 [RSSI: -69, LQI: 255] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:3, Counter:4 [RSSI: -75, LQI: 255] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:3, Counter:5 [RSSI: -75, LQI: 255] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:3, Counter:6 [RSSI: -71, LQI: 255] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:3, Counter:7 [RSSI: -74, LQI: 255] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:3, Counter:8 [RSSI: -90, LQI: 255] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:3, Counter:9 [RSSI: -84, LQI: 255] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:4, Counter:0 [RSSI: -80, LQI: 255] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:4, Counter:1 [RSSI: -78, LQI: 255] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:4, Counter:2 [RSSI: -83, LQI: 255] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:4, Counter:3 [RSSI: -80, LQI: 255] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:4, Counter:4 [RSSI: -81, LQI: 255] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:4, Counter:5 [RSSI: -82, LQI: 255] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:4, Counter:6 [RSSI: -83, LQI: 255] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:4, Counter:7 [RSSI: -69, LQI: 255] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:4, Counter:8 [RSSI: -64, LQI: 255] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:4, Counter:9 [RSSI: -63, LQI: 255] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:5, Counter:0 [RSSI: -77, LQI: 255] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:5, Counter:1 [RSSI: -81, LQI: 255] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:5, Counter:2 [RSSI: -80, LQI: 255] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:5, Counter:3 [RSSI: -83, LQI: 255] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:5, Counter:4 [RSSI: -78, LQI: 255] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:5, Counter:5 [RSSI: -80, LQI: 255] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:5, Counter:6 [RSSI: -81, LQI: 255] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:5, Counter:7 [RSSI: -83, LQI: 255] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:5, Counter:8 [RSSI: -80, LQI: 255] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:5, Counter:9 [RSSI: -80, LQI: 255] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:6, Counter:0 [RSSI: -84, LQI: 255] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:6, Counter:1 [RSSI: -86, LQI: 255] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:6, Counter:2 [RSSI: -85, LQI: 255] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:6, Counter:3 [RSSI: -81, LQI: 255] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:6, Counter:4 [RSSI: -82, LQI: 255] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:6, Counter:5 [RSSI: -90, LQI: 254] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:6, Counter:6 [RSSI: -81, LQI: 255] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:6, Counter:7 [RSSI: -83, LQI: 255] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:6, Counter:8 [RSSI: -83, LQI: 255] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:6, Counter:9 [RSSI: -85, LQI: 255] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:7, Counter:0 [RSSI: -71, LQI: 255] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:7, Counter:1 [RSSI: -73, LQI: 255] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:7, Counter:2 [RSSI: -71, LQI: 255] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:7, Counter:3 [RSSI: -74, LQI: 255] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:7, Counter:4 [RSSI: -72, LQI: 255] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:7, Counter:5 [RSSI: -73, LQI: 255] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:7, Counter:6 [RSSI: -73, LQI: 255] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:7, Counter:7 [RSSI: -73, LQI: 255] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:7, Counter:8 [RSSI: -74, LQI: 255] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:7, Counter:9 [RSSI: -71, LQI: 255] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:8, Counter:0 [RSSI: -86, LQI: 255] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:8, Counter:1 [RSSI: -93, LQI: 248] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:8, Counter:3 [RSSI: -86, LQI: 255] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:8, Counter:4 [RSSI: -85, LQI: 255] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:8, Counter:5 [RSSI: -84, LQI: 255] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:8, Counter:6 [RSSI: -87, LQI: 255] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:8, Counter:7 [RSSI: -92, LQI: 255] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:8, Counter:8 [RSSI: -87, LQI: 255] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:8, Counter:9 [RSSI: -94, LQI: 230] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:9, Counter:0 [RSSI: -94, LQI: 178] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:9, Counter:1 [RSSI: -95, LQI: 145] Page 12

13 RX [DATA] from: 000D6F00005C3ED4; len:48, Location:9, Counter:2 [RSSI: -97, LQI: 12] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:9, Counter:5 [RSSI: -96, LQI: 0] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:9, Counter:7 [RSSI: -90, LQI: 254] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:9, Counter:8 [RSSI: -93, LQI: 221] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:9, Counter:9 [RSSI: -90, LQI: 255] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:10, Counter:0 [RSSI: -85, LQI: 255] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:10, Counter:1 [RSSI: -85, LQI: 255] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:10, Counter:2 [RSSI: -82, LQI: 255] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:10, Counter:3 [RSSI: -85, LQI: 255] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:10, Counter:4 [RSSI: -84, LQI: 255] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:10, Counter:5 [RSSI: -85, LQI: 255] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:10, Counter:6 [RSSI: -88, LQI: 255] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:10, Counter:7 [RSSI: -84, LQI: 255] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:10, Counter:8 [RSSI: -87, LQI: 255] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:10, Counter:9 [RSSI: -86, LQI: 255] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:11, Counter:0 [RSSI: -81, LQI: 255] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:11, Counter:1 [RSSI: -80, LQI: 255] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:11, Counter:2 [RSSI: -80, LQI: 255] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:11, Counter:3 [RSSI: -77, LQI: 255] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:11, Counter:4 [RSSI: -80, LQI: 255] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:11, Counter:5 [RSSI: -76, LQI: 255] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:11, Counter:6 [RSSI: -76, LQI: 255] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:11, Counter:7 [RSSI: -79, LQI: 255] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:11, Counter:8 [RSSI: -83, LQI: 255] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:11, Counter:9 [RSSI: -83, LQI: 255] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:12, Counter:0 [RSSI: -71, LQI: 255] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:12, Counter:1 [RSSI: -73, LQI: 255] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:12, Counter:2 [RSSI: -74, LQI: 255] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:12, Counter:3 [RSSI: -71, LQI: 255] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:12, Counter:4 [RSSI: -72, LQI: 255] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:12, Counter:5 [RSSI: -77, LQI: 255] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:12, Counter:6 [RSSI: -73, LQI: 255] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:12, Counter:7 [RSSI: -73, LQI: 255] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:12, Counter:8 [RSSI: -74, LQI: 255] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:12, Counter:9 [RSSI: -75, LQI: 255] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:13, Counter:0 [RSSI: -67, LQI: 255] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:13, Counter:1 [RSSI: -67, LQI: 255] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:13, Counter:2 [RSSI: -72, LQI: 255] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:13, Counter:3 [RSSI: -74, LQI: 255] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:13, Counter:4 [RSSI: -75, LQI: 255] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:13, Counter:5 [RSSI: -74, LQI: 255] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:13, Counter:6 [RSSI: -76, LQI: 255] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:13, Counter:7 [RSSI: -69, LQI: 255] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:13, Counter:8 [RSSI: -73, LQI: 255] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:13, Counter:9 [RSSI: -76, LQI: 255] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:14, Counter:2 [RSSI: -91, LQI: 255] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:14, Counter:3 [RSSI: -94, LQI: 190] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:14, Counter:4 [RSSI: -87, LQI: 255] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:14, Counter:5 [RSSI: -87, LQI: 255] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:14, Counter:6 [RSSI: -89, LQI: 253] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:14, Counter:7 [RSSI: -85, LQI: 255] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:14, Counter:8 [RSSI: -88, LQI: 255] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:14, Counter:9 [RSSI: -89, LQI: 255] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:15, Counter:0 [RSSI: -96, LQI: 10] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:15, Counter:1 [RSSI: -91, LQI: 234] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:15, Counter:4 [RSSI: -93, LQI: 210] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:15, Counter:5 [RSSI: -93, LQI: 228] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:15, Counter:6 [RSSI: -94, LQI: 180] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:15, Counter:7 [RSSI: -90, LQI: 255] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:15, Counter:8 [RSSI: -91, LQI: 251] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:15, Counter:9 [RSSI: -88, LQI: 255] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:16, Counter:0 [RSSI: -94, LQI: 129] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:16, Counter:1 [RSSI: -89, LQI: 244] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:16, Counter:2 [RSSI: -92, LQI: 253] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:16, Counter:3 [RSSI: -95, LQI: 101] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:16, Counter:6 [RSSI: -96, LQI: 0] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:16, Counter:7 [RSSI: -90, LQI: 255] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:16, Counter:8 [RSSI: -92, LQI: 227] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:16, Counter:9 [RSSI: -89, LQI: 195] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:17, Counter:0 [RSSI: -96, LQI: 0] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:17, Counter:1 [RSSI: -94, LQI: 158] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:17, Counter:2 [RSSI: -95, LQI: 90] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:17, Counter:3 [RSSI: -94, LQI: 140] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:17, Counter:4 [RSSI: -91, LQI: 251] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:17, Counter:5 [RSSI: -88, LQI: 255] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:17, Counter:6 [RSSI: -91, LQI: 248] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:17, Counter:7 [RSSI: -90, LQI: 242] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:17, Counter:8 [RSSI: -86, LQI: 255] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:17, Counter:9 [RSSI: -91, LQI: 255] Page 13

14 RX [DATA] from: 000D6F00005C3ED4; len:48, Location:18, Counter:2 [RSSI: -96, LQI: 0] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:18, Counter:3 [RSSI: -95, LQI: 70] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:18, Counter:4 [RSSI: -93, LQI: 233] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:18, Counter:5 [RSSI: -96, LQI: 0] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:18, Counter:9 [RSSI: -92, LQI: 187] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:19, Counter:2 [RSSI: -96, LQI: 0] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:19, Counter:6 [RSSI: -96, LQI: 0] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:20, Counter:0 [RSSI: -90, LQI: 239] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:20, Counter:1 [RSSI: -92, LQI: 232] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:20, Counter:2 [RSSI: -95, LQI: 90] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:20, Counter:3 [RSSI: -91, LQI: 202] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:20, Counter:4 [RSSI: -90, LQI: 253] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:20, Counter:5 [RSSI: -88, LQI: 255] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:20, Counter:6 [RSSI: -93, LQI: 201] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:20, Counter:7 [RSSI: -92, LQI: 241] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:20, Counter:8 [RSSI: -89, LQI: 255] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:20, Counter:9 [RSSI: -93, LQI: 230] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:21, Counter:3 [RSSI: -96, LQI: 0] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:21, Counter:6 [RSSI: -96, LQI: 0] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:22, Counter:0 [RSSI: -95, LQI: 65] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:22, Counter:1 [RSSI: -94, LQI: 166] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:22, Counter:2 [RSSI: -92, LQI: 215] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:22, Counter:3 [RSSI: -93, LQI: 233] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:22, Counter:5 [RSSI: -90, LQI: 250] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:22, Counter:6 [RSSI: -93, LQI: 202] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:22, Counter:8 [RSSI: -96, LQI: 9] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:22, Counter:9 [RSSI: -93, LQI: 198] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:23, Counter:0 [RSSI: -97, LQI: 0] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:23, Counter:1 [RSSI: -96, LQI: 7] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:23, Counter:4 [RSSI: -94, LQI: 144] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:23, Counter:5 [RSSI: -93, LQI: 91] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:23, Counter:6 [RSSI: -92, LQI: 190] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:23, Counter:7 [RSSI: -92, LQI: 231] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:23, Counter:8 [RSSI: -96, LQI: 0] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:23, Counter:9 [RSSI: -94, LQI: 214] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:24, Counter:0 [RSSI: -89, LQI: 255] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:24, Counter:1 [RSSI: -93, LQI: 245] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:24, Counter:2 [RSSI: -94, LQI: 195] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:24, Counter:3 [RSSI: -91, LQI: 255] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:24, Counter:4 [RSSI: -93, LQI: 207] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:24, Counter:5 [RSSI: -95, LQI: 135] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:24, Counter:6 [RSSI: -89, LQI: 255] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:24, Counter:7 [RSSI: -92, LQI: 230] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:24, Counter:8 [RSSI: -91, LQI: 241] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:24, Counter:9 [RSSI: -93, LQI: 199] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:25, Counter:0 [RSSI: -95, LQI: 4] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:25, Counter:8 [RSSI: -96, LQI: 0] RX [DATA] from: 000D6F00005C3ED4; len:48, Location:25, Counter:9 [RSSI: -96, LQI: 0] Page 14