Received signal strength data of ZigBee technology for on-street environment at 2.4 GHz band and the interruption of vehicle to link quality

ZigBee technique is the common wireless network approaches for many smart indoor management applications such as home energy management or building management system. However, the application of ZigBee for outdoor applications is still not mature since the characteristic of signal strength depends on the outdoor conditions. To solve this issue, the received signal strength index (RSSI) and packet delivery are measured in real outdoor conditions for wireless neighborhood area network (WNAN) planning and optimization. Unfortunately, these important data are usually not publicly available for academic use. In this data article, RSSI data and packet delivery rate of a wireless network based on ZigBee 2.4 GHz are collected at the on-street condition, considering the effect of moving and stopping vehicles. In addition, the transmission ranges at two module location levels are also collected. The data provided in this article will help to estimate the transmission range, avoid the interferences and adjust the power level of ZigBee devices for many outdoor applications.


a b s t r a c t
ZigBee technique is the common wireless network approaches for many smart indoor management applications such as home energy management or building management system. However, the application of ZigBee for outdoor applications is still not mature since the characteristic of signal strength depends on the outdoor conditions. To solve this issue, the received signal strength index (RSSI) and packet delivery are measured in real outdoor conditions for wireless neighborhood area network (WNAN) planning and optimization. Unfortunately, these important data are usually not publicly available for academic use. In this data article, RSSI data and packet delivery rate of a wireless network based on ZigBee 2.4 GHz are collected at the on-street condition, considering the effect of moving and stopping vehicles. In addition, the transmission ranges at two module location levels are also collected. The data provided in this article will help to estimate the transmission range, avoid the interferences and adjust the power level of ZigBee devices for many outdoor applications.
& The loopback test mimicked the communication between a local controller station and a street lighting of a smart street lighting pilot project based on ZigBee at the same street. The parameters were adhered to as the suggested by this pilot project.

Experimental features
The statistical analyses and the probability distributions of the RSSI data are shown. The graphs are presented to show the interruption of moving and stopping vehicles to the link quality.
A correlation analysis of the communication range and the time of interruption was performed to understand the relationship between to datasets.

Data source location
The data in this article were gathered along a two-way street Rat Burana Road (three lanes each side), Bangkok, Thailand (Latitude 6.47385 o N, Longitude 3.00408 o E).

Data accessibility
Datasets on received signal strength at many range tests are provided in this article in easily reusable format.

Related research article
Mujahid Tabassum and Kartinah Zen, Performance evaluation of ZigBee in indoor and outdoor environment. In: 9th International Conference on IT in Asia (CITA), 4-5 August, 2015, pp. 1-7.

Value of the data
These data are needed by network engineers to understand the characteristics of ZigBee network at 2.4 GHz band used for many wireless outdoor applications such as smart street lighting network, traffic lighting network, smart electric meters network; This data provides valuable evidence about the impacts of running and stopping vehicles to the link quality of ZigBee network at 2.4 GHz band. Therefore, it is useful to consider for further tests and simulations; This dataset is a necessary input for the design and development of ZigBee signal propagation model, considering the interruption of vehicles.

Data
In this data article, the received signal strength index (RSSI) data and the packet delivery ratio of loopback range test of ZigBee 2.4 GHz were measured along the Rat Burana road, Bangkok, Thailand (Fig. 1). The collected data included two scenarios. In the first one, both ZigBee transmitter and receiver were located at the same street level (1.2 m from the ground). In the second one, the transmitter was located at the pedestrian overhead bridge (4.5 from the ground) while the receiver node was still at 1.2 m. The descriptive statistics of RSSI data are represented in Table 1

Loopback range test
This test helps to evaluate the existing street lighting network based on ZigBee 2.4 GHz. This project is hosted by Metropolitan Electricity Authority (MEA) company, Bangkok, Thailand (Fig. 1). Since the communication between ZigBee modules takes place over the street condition, the quality of the wireless signal can be affected by many factors such as reflection of waves, interferences, lineof-sight issues, device's location. The loopback test is a method used to perform the transmission of the links. This test involves sending data packets from the local ZigBee module to the remote one and waiting for the echo to be sent from the remote to the local.
The data collection and real-time analysis were performed with the use of the XCTU tool [1]. This tool counted the number of packets sent and received by the local module and measured the received signal strength value (RSSI). XCTU tool ran on a laptop Intel Core i3-2348M@2.30 GHz speed with 2GB RAM and Windows 7 operating system. The local module was connected to this laptop through USB cable. The remote module was power by a 10,000 Ah portable battery.

Parameter settings and scenarios
Our field test is to support the MEA company to evaluate their smart street lighting pilot project at Rat Burana road. The field test route includes a traffic light in order to investigate the impact of   running and stopping vehicles to the wireless link. The following parameters were adhered to as the suggested by this MEA: The Rx_timeout ¼ 10 (ms) Local module timeout when sending packet to remote module. After the packet has been sent, the radio of local module switches into receiving mode and waits for 10 seconds for the remote to respond.
The Tx_interval ¼ 400 (ms) This is the maximum interval, in microseconds, that the local module would like to use when transmitting packets.
Range test scenarios: There are two scenarios of the loopback range test.
■ Same level: Both local and remote modules are at 1.2 m height from the street ground (Fig. 6, right); ■ Different level: The remote module is located at the pedestrian overhead bridge with 4.5 m height from the street ground. The local module is at 1.2 m from the street ground.
An interference from stopping vehicles is identified when vehicles stop at the traffic light and the packet loss occurs in this period simultaneously.  Table 2 presents the summary of number of interferences caused by stopping vehicles at traffic light. Table 3 shows the Pearson correlation coefficients and P-values to evaluate the relationship between transmission range and number of interferences in the statistic aspect. The transmission length and number of interferences correlate poorly, however, within our project, we intend to represent the general relationship of data we have collected. And further research study will be done to investigate this correlation. Table 3 The Pearson correlation coefficients and P-values.

P-Value
Transmission length (same level) and number of interferences  Table 2 The summary of occurred interferences from stopping vehicles during the range tests.