(Portland, OR)  --  A homeless man is facing nearly two decades behind bars after killing a woman in North Portland over the summer.  A judge sentenced 58-year-old Terry Hickman to 17 years in prison yesterday.  Court records show he pleaded guilty to first-degree manslaughter and second-degree attempted assault last month for the death of 29-year-old Dallas Boyd-Riggins in July.  Police found her body inside Hickman's van.  An autopsy showed that she died of strangulation.  Hickman told police he choked her to death during an argument after a night of doing drugs together.