diff --git a/tests/signal_server/signal_server.cpp b/tests/signal_server/signal_server.cpp
index f2fc400..b1692f6 100644
--- a/tests/signal_server/signal_server.cpp
+++ b/tests/signal_server/signal_server.cpp
@@ -55,8 +55,20 @@ bool SignalServer::on_open(websocketpp::connection_hdl hdl) {
 
 bool SignalServer::on_close(websocketpp::connection_hdl hdl) {
   LOG_INFO("Websocket onnection [{}] closed", ws_connection_id_);
-  bool ret = transmission_manager_.ReleaseUserIdFromTransmission(hdl);
+  std::string transmission_id =
+      transmission_manager_.ReleaseUserIdFromTransmission(hdl);
+
+  std::vector<std::string> user_id_list =
+      transmission_manager_.GetAllUserIdOfTransmission(transmission_id);
+  json message = {{"type", "user_leave_transmission"},
+                  {"transmission_id", transmission_id},
+                  {"user_id", transmission_manager_.GetUserId(hdl)}};
+
+  for (const auto& user_id : user_id_list) {
+    send_msg(transmission_manager_.GetWsHandle(user_id), message);
+  }
   ws_connections_.erase(hdl);
+
   return true;
 }
 
diff --git a/tests/signal_server/transmission_manager.cpp b/tests/signal_server/transmission_manager.cpp
index 2379e46..395c782 100644
--- a/tests/signal_server/transmission_manager.cpp
+++ b/tests/signal_server/transmission_manager.cpp
@@ -52,24 +52,7 @@ bool TransmissionManager::BindUserIdToWsHandle(
   return true;
 }
 
-bool TransmissionManager::ReleaseWsHandleFromTransmission(
-    websocketpp::connection_hdl hdl) {
-  for (auto trans_it = transmission_user_ws_hdl_list_.begin();
-       trans_it != transmission_user_ws_hdl_list_.end(); ++trans_it) {
-    auto hdl_list = trans_it->second;
-    for (auto it = hdl_list.begin(); it != hdl_list.end(); ++it) {
-      if (it->lock().get() == hdl.lock().get()) {
-        hdl_list.erase(it);
-        LOG_INFO("Remove ws handle [{}] from transmission [{}]",
-                 hdl.lock().get(), trans_it->first);
-        return true;
-      }
-    }
-  }
-  return false;
-}
-
-bool TransmissionManager::ReleaseUserIdFromTransmission(
+std::string TransmissionManager::ReleaseUserIdFromTransmission(
     websocketpp::connection_hdl hdl) {
   for (auto it = user_id_ws_hdl_list_.begin(); it != user_id_ws_hdl_list_.end();
        ++it) {
@@ -84,12 +67,12 @@ bool TransmissionManager::ReleaseUserIdFromTransmission(
           LOG_INFO("Remove user id [{}] from transmission [{}]", it->first,
                    trans_it->first);
           user_id_ws_hdl_list_.erase(it);
-          return true;
+          return trans_it->first;
         }
       }
     }
   }
-  return false;
+  return "";
 }
 
 websocketpp::connection_hdl TransmissionManager::GetWsHandle(
@@ -100,4 +83,12 @@ websocketpp::connection_hdl TransmissionManager::GetWsHandle(
     websocketpp::connection_hdl hdl;
     return hdl;
   }
+}
+
+std::string TransmissionManager::GetUserId(websocketpp::connection_hdl hdl) {
+  for (auto it = user_id_ws_hdl_list_.begin(); it != user_id_ws_hdl_list_.end();
+       ++it) {
+    if (it->second.lock().get() == hdl.lock().get()) return it->first;
+  }
+  return "";
 }
\ No newline at end of file
diff --git a/tests/signal_server/transmission_manager.h b/tests/signal_server/transmission_manager.h
index b3a6136..5591619 100644
--- a/tests/signal_server/transmission_manager.h
+++ b/tests/signal_server/transmission_manager.h
@@ -20,28 +20,12 @@ class TransmissionManager {
   bool BindUserIdToWsHandle(const std::string& user_id,
                             websocketpp::connection_hdl hdl);
 
-  bool ReleaseWsHandleFromTransmission(websocketpp::connection_hdl hdl);
-  bool ReleaseUserIdFromTransmission(websocketpp::connection_hdl hdl);
+  std::string ReleaseUserIdFromTransmission(websocketpp::connection_hdl hdl);
 
   websocketpp::connection_hdl GetWsHandle(const std::string& user_id);
+  std::string GetUserId(websocketpp::connection_hdl hdl);
 
  private:
-  std::map<std::string, websocketpp::connection_hdl> transmission_host_list_;
-  std::map<std::string, std::vector<websocketpp::connection_hdl>>
-      transmission_guest_list_;
-
-  std::map<std::string, websocketpp::connection_hdl>
-      transmission_host_username_list_;
-  std::map<std::string, websocketpp::connection_hdl>
-      transmission_guest_username_list_;
-
- private:
-  std::map<std::string, std::vector<websocketpp::connection_hdl>>
-      transmission_user_ws_hdl_list_;
-  std::map<std::string, websocketpp::connection_hdl> username_ws_hdl_list_;
-
-  std::map<std::string, std::vector<std::string>> user_name_user_id_list_;
-
   std::map<std::string, std::vector<std::string>> transmission_user_id_list_;
   std::map<std::string, websocketpp::connection_hdl> user_id_ws_hdl_list_;
 };