Method and arrangement for interference variance reduction in a wireless communication system

Abstract

In a mobile communication network, a radio node and related method for reducing a signal-to-noise-and-interference ratio (SINR) requirement for a transmission in a scheduling interval. The node estimates a frequency resource utilization in the scheduling interval and compares the estimated utilization with a first threshold. When the estimated utilization is equal to or below the first threshold, the node increases the frequency resource utilization for the transmission, and adjusts a link adaptation for the transmission based on the increased frequency resource utilization. Optionally, the node may decrease the transmit power for the scheduling interval based on the adjusted link adaptation.

The invention claimed is: 
     
       1. A method in a radio node of a wireless communications system, of reducing a signal-to-noise-and-interference ratio requirement for at least one radio transmission in a scheduling interval, the at least one radio transmission being performed in a cell served by the radio node, the method comprising:
 estimating a frequency resource utilization in said scheduling interval; 
 comparing the estimated frequency resource utilization with a first threshold; and 
 when the estimated frequency resource utilization is equal to or below the first threshold:
 increasing the frequency resource utilization for the at least one radio transmission in such a manner as to allocate all resource blocks in the scheduling interval for corresponding radio transmissions; and 
 adjusting a link adaptation for the at least one radio transmission based on the increased frequency resource utilization; and 
 
 transmitting the at least one radio transmission in the cell served by the radio node. 
 
     
     
       2. The method according to  claim 1 , wherein when the estimated frequency resource utilization is above the first threshold, and an average transmission load in said cell is below a second threshold, the method further comprises:
 excluding an amount of delay-tolerant bits from the at least one radio transmission; 
 increasing the frequency resource utilization for the at least one radio transmission based on the excluded amount of delay-tolerant bits; and 
 adjusting the link adaptation for the at least one radio transmission based on the increased frequency resource utilization. 
 
     
     
       3. The method according to  claim 2 , wherein the second threshold is dynamically updated. 
     
     
       4. The method according to  claim 1 , further comprising decreasing a transmit power for said scheduling interval based on the adjusted link adaptation. 
     
     
       5. The method according to  claim 1 , wherein adjusting the link adaptation comprises adjusting a modulation. 
     
     
       6. The method according to  claim 1 , wherein adjusting the link adaptation comprises adjusting a code rate. 
     
     
       7. The method according to  claim 1 , wherein the first threshold is pre-defined. 
     
     
       8. The method according to  claim 1 , wherein the radio node is an evolved NodeB of a Long Term Evolution (LTE) system. 
     
     
       9. A radio node configured to be used in a wireless communications system, and to reduce a signal-to-noise-and-interference ratio requirement for at least one radio transmission in a scheduling interval, the at least one radio transmission being performed in a cell served by the radio node, the radio node comprising:
 an estimating circuit configured to estimate a frequency resource utilization in said scheduling interval; 
 a comparator coupled to the estimating circuit and a frequency resource allocation circuit configured to compare the estimated frequency resource utilization with a first threshold; 
 the frequency resource allocation circuit configured to increase the frequency resource utilization for the at least one radio transmission in such a manner as to allocate all resource blocks in the scheduling interval for corresponding radio transmissions, and to adjust a link adaptation for the at least one radio transmission based on the increased frequency resource utilization, when the comparator determines the estimated frequency resource utilization is equal to or below the first threshold; and 
 a transceiver configured to transmit the at least one radio transmission in the cell served by the radio node. 
 
     
     
       10. The radio node according to  claim 9 , further comprising:
 an excluding circuit configured to exclude an amount of delay-tolerant bits from the at least one radio transmission, when the estimated frequency resource utilization is above the first threshold, and an average transmission load in said cell is below a second threshold; 
 wherein the frequency resource allocation circuit is further configured to increase the frequency resource utilization for the at least one radio transmission based on the excluded amount of delay-tolerant bits. 
 
     
     
       11. The radio node according to  claim 10 , wherein the second threshold is dynamically updated. 
     
     
       12. The radio node according to  claim 9 , further comprising a power control circuit configured to decrease a transmit power for said scheduling interval based on the adjusted link adaptation. 
     
     
       13. The radio node according to  claim 9 , wherein the frequency resource allocation circuit is further configured to adjust the link adaptation through adjusting a modulation. 
     
     
       14. The radio node according to  claim 9 , wherein the frequency resource allocation circuit is further configured to adjust the link adaptation through adjusting a code rate. 
     
     
       15. The radio node according to  claim 9  wherein the first threshold is predefined. 
     
     
       16. The radio node according to  claim 9 , wherein the radio node is an evolved NodeB of a Long Term Evolution (LTE) system.