Small Cell Base Station DTX Mode

Abstract

The present disclosure is directed to a system and method for transitioning small cell base stations out of a discontinuous transmission (DTX) mode. The system and method comprise monitoring at the small cell base stations uplink transmissions from user terminals (UTs) to a macrocell base station while the small cell base stations are in the DTX mode. The small cell base stations can use the monitored uplink transmissions to, for example, measure received power levels from the UTs and/or measure uplink path losses between the small cell base stations and the UTs. The small cell base stations can report these measured values back to the macrocell base station through a backhaul network. Based on these measurements, the macrocell base station can determine which small cell base stations can support which UTs without transitioning the small cell base stations out of the DTX mode.

What is claimed is: 
     
         1 . A method for transitioning a small cell base station out of a discontinuous transmission (DTX) mode, the method comprising:
 monitoring, at the small cell base station, an uplink transmission to a macrocell base station from a user terminal (UT) while the small cell base station is in the DTX mode;   reporting, to the macrocell base station, a measured received power associated with the uplink transmission and an uplink path loss measurement associated with the uplink transmission; and   transitioning the small cell base station out of the DTX mode if instructed to by the macrocell base station based on the reported measured received power associated with the uplink transmission and the reported uplink path loss measurement associated with the uplink transmission.   
     
     
         2 . The method of  claim 1 , wherein the monitoring is performed based on a traffic load condition at the marcocell. 
     
     
         3 . The method of  claim 1 , wherein the monitoring is performed if the macrocell base station is unable to handle a traffic load at a required quality of service level. 
     
     
         4 . The method of  claim 1 , further comprising:
 receiving from the macrocell base station a UT identification, an uplink resource allocation, a code rate, and a modulation scheme to be used by the UT to transmit the uplink transmission.   
     
     
         5 . The method of  claim 4 , wherein the UT identification, the uplink resource allocation, the code rate, and the modulation scheme are received from the macrocell base station over a backhaul network. 
     
     
         6 . The method of  claim 4 , wherein the UT identification, the uplink resource allocation, the code rate, and the modulation scheme are received from the macrocell base station via a downlink transmission to the UT. 
     
     
         7 . The method of  claim 4 , further comprising:
 decoding the uplink transmission using the uplink resource allocation, the code rate, and the modulation scheme to verify that the small cell base station is able to properly decode the uplink transmission.   
     
     
         8 . The method of  claim 1 , wherein the measured received powers associated with the uplink transmission are determined based on pilot signals sent by the UT in the uplink transmission. 
     
     
         9 . The method of  claim 1 , wherein the macrocell base station uses the reported measured received power associated with the uplink transmission to determine whether the small cell base station is able to support a quality of service level in the uplink direction from the UT to the small cell base station. 
     
     
         10 . The method of  claim 1 , wherein the macrocell base station uses the reported path loss measurement associated with the uplink transmission to determine whether the small cell base station is able to support a quality of service level in the downlink direction from the small cell base station to the UT. 
     
     
         11 . A small cell base station, comprising:
 a receiver configured to monitor an uplink transmission to a macrocell base station from a user terminal (UT) while the small cell base station is in a discontinuous transmission (DTX) mode; and   a baseband processor configured to report to the macrocell base station a measured received power associated with the uplink transmission and uplink path loss measurement associated with the uplink transmission.   
     
     
         12 . The small cell base station of  claim 11 , wherein the baseband processor is further configured to transition the small cell base station out of the DTX mode if instructed to by the macrocell base station based on the reported measured received power associated with the uplink transmission and the reported uplink path loss measurement associated with the uplink transmission. 
     
     
         13 . The small cell base station of  claim 11 , further comprising:
 a transmitter configured to transmit downlink to the UT,   wherein the baseband processor is configured to transition the small cell base station out of the DTX mode by powering up the transmitter.   
     
     
         14 . The small cell base station of  claim 11 , wherein the receiver is powered down prior to monitoring the uplink transmission. 
     
     
         15 . The small cell base station of  claim 11 , wherein the receiver monitors the uplink transmission based on a traffic load. 
     
     
         16 . The small cell base station of  claim 11 , wherein the receiver is further configured to receive from the macrocell base station a message comprising a UT identification, an uplink resource allocation, a code rate, and a modulation scheme to be used by the UT to transmit the uplink transmission. 
     
     
         17 . The small cell base station of  claim 11 , wherein the receiver is further configured to receive from the macrocell base station via a downlink transmission to the UT a UT identification, an uplink resource allocation, a code rate, and a modulation scheme to be used by the UT to transmit the uplink transmission. 
     
     
         18 . A method for transitioning a small cell base station out of a discontinuous transmission (DTX) mode, the method comprising:
 monitoring, at the small cell base station, an uplink transmission to a macrocell base station from a user terminal (UT) while the small cell base station is in the DTX mode;   reporting, to the macrocell base station, a measured received power associated with the uplink transmission based on the small cell base station properly decoding the uplink transmission; and   transitioning the small cell base station out of the DTX mode if instructed to by the macrocell base station based on the reported measured received power associated with the uplink transmission.   
     
     
         19 . The method of  claim 18 , wherein the monitoring is performed based on a traffic load. 
     
     
         20 . The method of  claim 18 , wherein the macrocell base station uses the reported measured received power associated with the uplink transmission to determine whether the small cell base station is able to support a quality of service level in the uplink direction from the UT to the small cell base station.