Ned Whalley| The Daily Star
BEIRUT: Alfa representative detailed how his network pieced together records for submission to the Special Tribunal for Lebanon Monday, as it attempted to produce maps reflecting cellular coverage at the time of the Rafik Hariri assassination. Cell siting – tracking the location of cell phone users – is crucial to the prosecution’s case. Investigators identified the defendants and brought charges against them based on information gleaned from analysis of cellular data and billing records. They are attempting to use it to demonstrate conclusively that the five members of Hezbollah, still at large, plotted and perpetrated the bombing that killed the former prime minister.
The anonymous Alfa representative described how his company produced maps of coverage for investigators in response to requests from the office of the prosecutor. The development of newer, purportedly more accurate models led Alfa to submit additional information to investigators in 2010, 2013, and 2015.
Propagation models are used by cellular networks to develop and expand their networks, and are regularly updated to try to minimize the disparity between actual and predicted coverage. Investigators are interested in them because they allow them to locate phones as they connect with particular cell sites during a call. This information can help identify the user and place them in a specific place at a specific time.
Much of the witness’ testimony over the last week pertains to the accuracy of such maps, which are created from models developed by the company’s engineers in concert with the equipment manufacturer. They are intended to take into account any physical features that could affect the transmission of radio waves between a phone and a cell site, but production of accurate maps has been complicated by the absence of technical data from 2005 and changes to the network in the interim period.
The witness said his team has had to piece together a range of information from old files in an effort to map the coverage as it would have existed in 2004-5. The extent to which the court is convinced that their replication is reliable could make or break the case.
Judges asked a number of questions about how coverage might have changed between the assassination and 2007, the earliest year for which Alfa has records on the positioning of antennae at its cell sites. They drew particular attention to the massive changes wrought to the Beirut skyline by bombing in the summer 2006 war, especially in the Beirut southern suburbs, and subsequent construction.
The witness testified his team had conducted extensive research, verifying the geographic coordinates of nearly a thousand cell sites, and said that changes to the positions of their antennae would likely have been minor. He said that although the network had moved quickly to address damage to the network after the conflict, it had been a relatively stable period in terms of the construction of new sites.
“There weren’t a lot of changes during that period, that is the information available to us,” he said.
Throughout his testimony he stressed the continuity of the network’s infrastructure, arguing that even the construction of a large building next to a cell site would likely result in the repositioning of an antenna rather than a wholesale relocation of the site. The intent in such situations was to maintain coverage as it existed, as any dramatic reconfiguration might cause difficulties elsewhere in the network.
The evidence of the witness has been repeatedly contested by defense attorneys, who contend that he should not be allowed to testify to the veracity of information provided by other members of the company. It is likely he will be similarly challenged on the extent of his first-hand knowledge during cross-examination.
The tribunal is scheduled to resume Tuesday morning.
Copyrights 2016, The Daily Star - All Rights Reserved
Source & Link : The Daily Star
BEIRUT: Alfa representative detailed how his network pieced together records for submission to the Special Tribunal for Lebanon Monday, as it attempted to produce maps reflecting cellular coverage at the time of the Rafik Hariri assassination. Cell siting – tracking the location of cell phone users – is crucial to the prosecution’s case. Investigators identified the defendants and brought charges against them based on information gleaned from analysis of cellular data and billing records. They are attempting to use it to demonstrate conclusively that the five members of Hezbollah, still at large, plotted and perpetrated the bombing that killed the former prime minister.
The anonymous Alfa representative described how his company produced maps of coverage for investigators in response to requests from the office of the prosecutor. The development of newer, purportedly more accurate models led Alfa to submit additional information to investigators in 2010, 2013, and 2015.
Propagation models are used by cellular networks to develop and expand their networks, and are regularly updated to try to minimize the disparity between actual and predicted coverage. Investigators are interested in them because they allow them to locate phones as they connect with particular cell sites during a call. This information can help identify the user and place them in a specific place at a specific time.
Much of the witness’ testimony over the last week pertains to the accuracy of such maps, which are created from models developed by the company’s engineers in concert with the equipment manufacturer. They are intended to take into account any physical features that could affect the transmission of radio waves between a phone and a cell site, but production of accurate maps has been complicated by the absence of technical data from 2005 and changes to the network in the interim period.
The witness said his team has had to piece together a range of information from old files in an effort to map the coverage as it would have existed in 2004-5. The extent to which the court is convinced that their replication is reliable could make or break the case.
Judges asked a number of questions about how coverage might have changed between the assassination and 2007, the earliest year for which Alfa has records on the positioning of antennae at its cell sites. They drew particular attention to the massive changes wrought to the Beirut skyline by bombing in the summer 2006 war, especially in the Beirut southern suburbs, and subsequent construction.
The witness testified his team had conducted extensive research, verifying the geographic coordinates of nearly a thousand cell sites, and said that changes to the positions of their antennae would likely have been minor. He said that although the network had moved quickly to address damage to the network after the conflict, it had been a relatively stable period in terms of the construction of new sites.
“There weren’t a lot of changes during that period, that is the information available to us,” he said.
Throughout his testimony he stressed the continuity of the network’s infrastructure, arguing that even the construction of a large building next to a cell site would likely result in the repositioning of an antenna rather than a wholesale relocation of the site. The intent in such situations was to maintain coverage as it existed, as any dramatic reconfiguration might cause difficulties elsewhere in the network.
The evidence of the witness has been repeatedly contested by defense attorneys, who contend that he should not be allowed to testify to the veracity of information provided by other members of the company. It is likely he will be similarly challenged on the extent of his first-hand knowledge during cross-examination.
The tribunal is scheduled to resume Tuesday morning.
Copyrights 2016, The Daily Star - All Rights Reserved
Source & Link : The Daily Star
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