Inter-cell messaging using mbsfn subframe

Abstract

A cellular communication system and method for delivering information, e.g., data and/or control-signaling, to a user equipment (UE) from a neighboring node are disclosed. The cellular communication system includes a first node configured to transmit information in one or more Multicast Broadcast Single Frequency Network (MBSFN) subframes over a radio frequency (RF) link between the first node and the UE, while the UE is being served by a second node. The first node can use a network-defined, dedicated portion of the MBSFN subframe for this purpose. Instead of only allowing the second node to send data/signaling messages to the UE, the disclosed techniques allow neighboring nodes to also deliver information to the UE. In particular, the neighboring nodes can transmit data and/or control-signaling to the UE using MBSFN subframes in order to minimize signaling overhead and signaling delay.

What is claimed is: 
     
         1 . A cellular communication system, comprising:
 a plurality of nodes communicatively coupled via a backhaul network,   where a first node of the plurality of nodes is configured to transmit information to a user equipment (UE) being served by a second node, the information being transmitted by unicast message in a Multicast Broadcast Single Frequency Network (MBSFN) subframe or portion thereof reserved only for data transmitted by the first node, the information including control information or unicast data for the UE.   
     
     
         2 . The cellular communication system of  claim 1 , further comprising:
 the second node configured to select the first node based upon predetermined criteria and transfer UE-specific signaling information to the first node as a result of the first node being selected.   
     
     
         3 . The cellular communication system of  claim 2 , wherein the predetermined criteria include one or more measurement reports from the UE. 
     
     
         4 . The cellular communication system of  claim 1 , wherein the first node is configured to transmit UE-specific information in a first MBSFN subframe, and the second node is configured to not transmit in the first MBSFN subframe. 
     
     
         5 . The cellular communication system of  claim 4 , wherein the second node is configured to transmit in a second MBSFN subframe and the first node is configured to not transmit in the second MBSFN subframe. 
     
     
         6 . The cellular communication system of  claim 1 , wherein the MBSFN subframe is split into a plurality of carrier sub-bands each having a different frequency band and the first node is configured to transmit the information in a first carrier sub-band, and the second node is configured to not transmit in the first carrier sub-band during the MBSFN subframe. 
     
     
         7 . The cellular communication system of  claim 6 , wherein the first node is configured to not transmit in the second carrier sub-band during the MBSFN subframe. 
     
     
         8 . The cellular communication system of  claim 1 , wherein the MBSFN subframe is split into a plurality of time slots, and the first node is configured to transmit the information in the first time slot, and the second node is configured to not transmit in the first time slot. 
     
     
         9 . The cellular communication system of  claim 8 , wherein the second node is configured to transmit in the second time slot, and the first node is configured to not transmit in the second time slot. 
     
     
         10 . The cellular communication system of  claim 1 , wherein the first node is assigned a first spreading code and the second node is assigned a second spreading code different from the first spreading code, and the first node is configured to spread first information using the first spreading code, whereby producing spread first information, and to transmit the spread first information in the MBSFN subframe, and the second node is configured to spread second information using the second spreading code, whereby producing second spread information, and to transmit the spread second information in the MBSFN subframe. 
     
     
         11 . A method of transmitting information in a cellular communication system, comprising:
 transmitting information from a first node to a user equipment (UE) being served by a second node, the information being transmitted by unicast message in a Multicast Broadcast Single Frequency Network (MBSFN) subframe or portion thereof reserved only for data transmitted by the first node, the information including control information or unicast data for the UE.   
     
     
         12 . The method of  claim 11 , further comprising:
 providing services to the UE from the second node;   selecting the first node based upon predetermined criteria; and   transferring UE-specific signaling information from the second node to the first node as a result of the first node being selected.   
     
     
         13 . The method of  claim 12 , wherein the predetermined criteria include one or more measurement reports from the UE. 
     
     
         14 . The method of  claim 11 , wherein the first node is configured to transmit UE-specific information in a first MBSFN subframe, and the second node is configured to not transmit in the first MBSFN subframe. 
     
     
         15 . The method of  claim 14 , wherein the second node is configured to transmit in a second MBSFN subframe and the first node is configured to not transmit in the second MBSFN subframe. 
     
     
         16 . The method of  claim 11 , wherein the MBSFN subframe is split into a plurality of carrier sub-bands each having a different frequency band and the first node is configured to transmit the information only in the first MBSFN sub-band, and the second node is configured to not transmit in the first carrier sub-band during the MBSFN subframe. 
     
     
         17 . The method of  claim 11 , wherein the MBSFN subframe is split into a plurality of time slots, and the first node is configured to transmit the information in the first time slot, and the second node is configured to not transmit in the first time slot. 
     
     
         18 . The method of  claim 17 , wherein the second node is configured to transmit in the second time slot, and the first node is configured to not transmit in the second time slot. 
     
     
         19 . The method of  claim 11 , wherein the first node is assigned a first spreading code and the second node is assigned a second spreading code different from the first spreading code, and the first node is configured to spread first information using the first spreading code, whereby producing spread first information, and to transmit the spread first information in the MBSFN subframe, and the second node is configured to spread second information using the second spreading code, whereby producing second spread information, and to transmit the spread second information in the MBSFN subframe. 
     
     
         20 . A first node comprising:
 a transmitter configured to transmit information to a user equipment (UE) being served by a second node, the information being transmitted by unicast message in a Multicast Broadcast Single Frequency Network (MBSFN) subframe or portion thereof reserved only for data transmitted by the first node, the information including control information or unicast data for the UE.