diff --git a/owlps-positioner/mobile.cc b/owlps-positioner/mobile.cc
index 6dfb2a3..e728166 100644
--- a/owlps-positioner/mobile.cc
+++ b/owlps-positioner/mobile.cc
@@ -13,6 +13,47 @@
 
 
 #include "mobile.hh"
+#include "request.hh"
+
+
+
+/* *** Constructors *** */
+
+
+Mobile::Mobile(const Mobile &m):
+  WifiDevice(m), last_results(m.last_results)
+{
+  update_last_request() ;
+}
+
+
+Mobile::~Mobile()
+{
+  if (last_request)
+    delete last_request ;
+}
+
+
+
+/* *** Write accessors *** */
+
+
+void Mobile::update_last_request()
+{
+  if (last_results.empty())
+    {
+      delete last_request ;
+      last_request = nullptr ;
+      return ;
+    }
+
+  if (! last_request)
+    last_request = new Request(*last_results.get_request()) ;
+  else
+    *last_request = *last_results.get_request() ;
+
+  last_results.set_request(last_request) ;
+}
 
 
 
diff --git a/owlps-positioner/mobile.hh b/owlps-positioner/mobile.hh
index ab47eb7..ef0faef 100644
--- a/owlps-positioner/mobile.hh
+++ b/owlps-positioner/mobile.hh
@@ -15,6 +15,8 @@
 #ifndef _OWLPS_POSITIONING_MOBILE_HH_
 #define _OWLPS_POSITIONING_MOBILE_HH_
 
+class Request ;
+
 #include "wifidevice.hh"
 #include "resultlist.hh"
 
@@ -26,7 +28,18 @@
 /// localised
 class Mobile: public WifiDevice
 {
+private:
+  /// Last request received from this mobile
+  Request *last_request ;
+
+  /** @name Write accessors */
+  //@{
+  /// Updates last_request from last_results
+  void update_last_request(void) ;
+  //@}
+
 protected:
+  /// Last results computed for this mobile
   ResultList last_results ;
 
 public:
@@ -34,15 +47,15 @@ public:
          const std::string &_mac_addr = "",
          const float _antenna_gain = MOBILE_DEFAULT_ANTENNA_GAIN,
          const float _trx_power = WIFIDEVICE_DEFAULT_TRX_POWER):
-    WifiDevice(_ip_addr, _mac_addr, _antenna_gain, _trx_power) {}
+    WifiDevice(_ip_addr, _mac_addr, _antenna_gain, _trx_power),
+    last_request(nullptr) {}
 
   Mobile(const WifiDevice &wd):
-    WifiDevice(wd) {}
+    WifiDevice(wd), last_request(nullptr) {}
 
-  Mobile(const Mobile &m):
-    WifiDevice(m), last_results(m.last_results) {}
+  Mobile(const Mobile &m) ;
 
-  ~Mobile(void) {}
+  ~Mobile(void) ;
 
   /** @name Read accessors */
   //@{
@@ -83,6 +96,7 @@ inline const ResultList& Mobile::get_last_results() const
 inline void Mobile::set_last_results(const ResultList &_last_results)
 {
   last_results = _last_results ;
+  update_last_request() ;
 }