DOI: 10.21227/bda7-rh85
title: CRAWDAD rutgers/noise

description: We performed experiments wherein noise injection was used as a method for mapping real world wireless network topologies onto the ORBIT testbed. This dataset includes received signal strength indicator (RSSI) for each correctly received frame at receiver nodes for different levels of noise injected on the ORBIT testbed.last modified : 2007-05-29release date : 2007-04-20date/time of measurement start : 2005-10-15date/time of measurement end : 2005-10-15collection environment : To evaluate routing protocols on a controlled indoor wireless testbed, the radio range must be compressed so that larger multi-hop topologies can be mapped into a laboratory size area. We propose noise injection as a more flexible option than hardware attenuation and consider methods for mapping real world wireless network topologies onto the testbed. We performed experiments for a free space propagation environment. By selecting node positions through an automated procedure, we were able to create a 5-node/4-hop string topology and a random partially connected 6-node topology in a 8m by 8m area with off-the-shelf IEEE 802.11 hardware.network configuration : One example of a controlled indoor testbed is provided by the Open Access Research Testbed for Next-Generation Wireless Networks (ORBIT). ORBIT's prototype indoor testbed comprises 128 IEEE 802.11a/b/g radio interfaces attached to 64 static nodes arranged on an 8 by 8 grid. The antennas are mounted on the sides of crates, at 45 and 225 degree positions when looking at the topside of a node and are connected through shielded cables to the Atheros-based wireless cards. Every node is a small form factor PC with 1GHz Via C3 CPU, 512 MB RAM, 20 GB hard disk and three ethernet ports, one of which is used for node configuration and control. The ORBIT grid used is a 8 by 8 square grid consisting of 64 radio nodes, 32 of them fitted with two Atheros 5212-based IEEE 802.11a/b/g cards each. The remaining are Intel cards. We use Atheros cards for all our experiments as we found the drivers more open and malleable than others.data collection methodology : Each node runs a Debian Linux distribution with 2.4.26 kernel and uses the madwifi stripped driver.2 This allows generation and processing of raw IEEE802.11 encapsulated frames from the Click Modular Router. One node is configured in Master mode to transmit 802.11 beacon packets, while all other nodes act as receivers. Thus packet error due to collisions is not a possibility. The receivers' driver provides all received MAC frames encapsulated with a so-called Prism header that contains bitrate, received signal strength indicator (RSSI), and other physical layer information. A Click script on the receiver extracts and logs the sequence number and RSSI for each correctly received frame.Tracesetrutgers/noise/RSSITraceset of RSSI measurement on the ORBIT testbed.files: dbm0.tar.gz, dbm-5.tar.gz, dbm-10.tar.gz, dbm-15.tar.gz, dbm-20.tar.gzdescription: This traceset includes received signal strength indicator (RSSI) for each correctly received frame at recever nodes when various levels of noises are injected on the ORBIT testbed.measurement purpose: Routing Protocolmethodology: We assume that an experimenter has access to a number of interferers and a number of nodes that can act as senders and receivers. The interferers are configured to emit additive white Gaussian noise (AWGN) with an experimenter-specified center frequency, bandwidth, and power level. The experimenter can adjust the positions of both the interferers and nodes within a square area (either by physically rearranging nodes or, if working with a stationary testbed, the experimenter may select nodes close to the intended positions from a larger number of candidates). The interference levels are configurable at the interferers and can be used to vary the link conditions between any two nodes. The experimenter can also control bitrate and transmission power on the senders. We define the radio mapping problem as follows: Given a virtual scenario with a set of n nodes and a time-invariant virtual packet error rate on every link between two nodes, configure the testbed so that the packet error rate (PER) on the links between the chosen testbed nodes approximates the PER in the virtual scenario (note that we do not consider packet collisions when we refer to PER). As mapping algorithms, we consider an automated Select Nodes with Fixed Interference (SNFI) procedure and compare it against a manual Select Interference for Fixed Nodes (SIFN) procedure as a baseline. For details about SNFI and SIFN procedures, please refer to [kaul-topologies]. We implemented the SNFI algorithm in a Perl script, that executes on a server and can remotely execute commands on the nodes through ssh. Log files were copied back to the server and the packet error rate (PER) at each receiver node is calculated as 1-N_r/N_t, where N_r is the number of packets in the log file and N_t is the number of transmitted beacons. Since the transmitter sends one beacon per 100ms, N_t = d/100ms, where d is the duration of the experiment in milliseconds. The testbed supports additive white Gaussian noise interference generation at center frequencies of 250KHz to 6GHz. An Agilent E4438C ESG vector signal generator provides the interference signal. Let us refer to each node as node (x,y), where x is the row index and y is the column index (both in the interval [1, 8]). The signal generator is connected to four omni-directional noise antennae, placed between node (2,1) and node (2,2); node (2,7) and node (2, 8); node (7,1) and node(7,2); and node (7,7) and node (7,8). The noise power is split equally amongst the noise antennae. An amplifier is used to amplify the signal from the ESG before it is split amongst the noise antennae. The amplifier approximately compensates for any losses in the coaxial cables that connect the ESG to the antennae. All experiments carried out used I/Q modulated AWGN as the interference. Noise power can be varied between -95dbm and -5dbm (at a granularity of 0.5dbm), and distributed over a noise bandwidth of up to 40MHz. Unless otherwise mentioned the wireless cards and the noise generator use the configuration shown in table II in [kaul-topologies]. We selected the highest transmit power and lowest available bitrate for these experiments, because they result in largest possible transmission range and so present the most challenging scenario for our approach. Unless otherwise mentioned PER was measured over a period of 30sec. The receivers' driver provides all received MAC frames encapsulated with a so-called Prism header that contains bitrate, received signal strength indicator (RSSI), and other physical layer information. A Click script on the receiver extracts and logs the sequence number and RSSI for each correctly received frame.rutgers/noise/RSSI Tracesdbm0: Trace of RSSI measurement on the ORBIT testbed.configuration: The data includes measurements made at 0 dbm for each node configured as transmitter.format:The main directory in the tar file consists of sub directorieseach of which corresponds to measurements for a selected transmitterand noise level.Each sub-directory is named asResults_node-_DailyTest_---__-where x, y are co-ordinates of the grid node that was configured as transmitter.In each sub-directory, we store the sequence number and RSSI for each packet receivedat each receiver node as a file named assdec-where rx-x, rx-y are the grid co-ordinates of the receiver nodes.dbm-5: Trace of RSSI measurement on the ORBIT testbed.configuration: The data includes measurements made at -5 dbm for each node configured as transmitter.format:The main directory in the tar file consists of sub directorieseach of which corresponds to measurements for a selected transmitterand noise level. Each sub-directory is named as Results_node-_DailyTest_---__-where x, y are co-ordinates of the grid node that was configured as transmitter.In each sub-directory, we store the sequence number and RSSI for each packet receivedat each receiver node as a file named assdec-where rx-x, rx-y are the grid co-ordinates of the receiver nodes.dbm-10: Trace of RSSI measurement on the ORBIT testbed.configuration: The data includes measurements made at -10 dbm for each node configured as transmitter.format:The main directory in the tar file consists of sub directorieseach of which corresponds to measurements for a selected transmitterand noise level. Each sub-directory is named as Results_node-_DailyTest_---__-where x, y are co-ordinates of the grid node that was configured as transmitter.In each sub-directory, we store the sequence number and RSSI for each packet receivedat each receiver node as a file named assdec-where rx-x, rx-y are the grid co-ordinates of the receiver nodes.dbm-15: Trace of RSSI measurement on the ORBIT testbed.configuration: The data includes measurements made at -15 dbm for each node configured as transmitter.format:The main directory in the tar file consists of sub directorieseach of which corresponds to measurements for a selected transmitterand noise level. Each sub-directory is named as Results_node-_DailyTest_---__-where x, y are co-ordinates of the grid node that was configured as transmitter.In each sub-directory, we store the sequence number and RSSI for each packet receivedat each receiver node as a file named assdec-where rx-x, rx-y are the grid co-ordinates of the receiver nodes.dbm-20: Trace of RSSI measurement on the ORBIT testbed.configuration: The data includes measurements made at -20 dbm for each node configured as transmitter.format:The main directory in the tar file consists of sub directorieseach of which corresponds to measurements for a selected transmitterand noise level. Each sub-directory is named as Results_node-_DailyTest_---__-where x, y are co-ordinates of the grid node that was configured as transmitter.In each sub-directory, we store the sequence number and RSSI for each packet receivedat each receiver node as a file named assdec-where rx-x, rx-y are the grid co-ordinates of the receiver nodes.