Table design for 256 quadrature amplitude modulation

Abstract

According to some embodiments, a method of determining a modulation coding scheme in a wireless network comprises receiving a CQI index, wherein the CQI index comprises a four-bit value associated with a channel quality of a wireless signal and identifying an entry in a CQI table based on the CQI index. The CQI table comprises: a first contiguous plurality of table entries associated with low SINR and a first modulating scheme; a second contiguous plurality of table entries associated with medium SINR and a second modulation coding scheme; and a third contiguous plurality of table entries associated with high SINR and with one of either a third or a fourth modulation coding scheme. The method further comprises determining a modulation coding scheme based on the identified entry in the CQI table and encoding a transmission block according to the determined modulation coding scheme.

1 . A method of determining a modulation coding scheme in a wireless network, the method comprising:
 receiving a channel quality indicator (CQI) index from a wireless device, wherein the CQI index comprises a four-bit value associated with a channel quality of a wireless signal;   identifying an entry in a CQI table based on the CQI index, wherein the CQI table comprises:
 a first contiguous plurality of at least three table entries associated with low SINR and a first modulation coding scheme; and 
 a second contiguous plurality of at least three table entries associated with medium SINR and a second modulation coding scheme; and 
 a third contiguous plurality of table entries associated with high SINR, wherein the third contiguous plurality of table entries comprises a portion of entries associated with a third modulation coding scheme and a portion of entries associated with a fourth modulation coding scheme; and 
   determining a modulation coding scheme based on the identified entry in the CQI table; and   indicating, to the wireless device, the determined modulation coding scheme to be used for downlink data transmission.   
     
     
         2 . The method of  claim 1 , wherein:
 the first sampling grid comprises a grid spacing of approximately 3dB;   the second sampling grid comprises a grid spacing of approximately 2dB; and   the third sampling grid comprises a grid spacing of approximately 2.5dB.   
     
     
         3 . The method of  claim 1 , wherein:
 the first contiguous plurality of table entries comprises Quadrature Phase Shift Keying (QPSK) entries;   the second contiguous plurality of table entries comprises 16 Quadrature Amplitude Modulation (16QAM) entries; and   the third contiguous plurality of table entries comprises 64 Quadrature Amplitude Modulation (64QAM) entries and 256 Quadrature Amplitude Modulation (256QAM) entries.   
     
     
         4 . The method of  claim 1 , wherein:
 the first contiguous plurality of table entries comprises four entries;   the second contiguous plurality of table entries comprises three entries; and   the third contiguous plurality of table entries comprises eight entries.   
     
     
         5 . The method of  claim 1 , wherein the third contiguous plurality of table entries comprises four 64QAM entries and four 256QAM entries. 
     
     
         6 . A radio network node in a wireless network comprising a processor operable to:
 receive a channel quality indicator (CQI) index from a wireless device, wherein the CQI index comprises a four-bit value associated with a channel quality of a wireless signal;   identify an entry in a CQI table based on the CQI index, wherein the CQI table comprises:
 a first contiguous plurality of at least three table entries associated with low SINR and a first modulation coding scheme; and 
 a second contiguous plurality of at least three table entries associated with medium SINR and a second modulation coding scheme; and 
 a third contiguous plurality of table entries associated with high SINR, wherein the third contiguous plurality of table entries comprises a portion of entries associated with a third modulation coding scheme and a portion of entries associated with a fourth modulation coding scheme; and 
   determine a modulation coding scheme based on the identified entry in the CQI table; and   indicate, to the wireless device, the determined modulation coding scheme to be used for downlink data transmission.   
     
     
         7 . The radio network node of  claim 6 , wherein:
 the first sampling grid comprises a grid spacing of approximately 3dB;   the second sampling grid comprises a grid spacing of approximately 2dB; and   the third sampling grid comprises a grid spacing of approximately 2.5dB.   
     
     
         8 . The radio network node of  claim 6 , wherein:
 the first contiguous plurality of table entries comprises Quadrature Phase Shift Keying (QPSK) entries;   the second contiguous plurality of table entries comprises 16 Quadrature Amplitude Modulation (16QAM) entries; and   the third contiguous plurality of table entries comprises 64 Quadrature Amplitude Modulation (64QAM) entries and 256 Quadrature Amplitude Modulation (256QAM) entries.   
     
     
         9 . The radio network node of  claim 6 , wherein:
 the first contiguous plurality of table entries comprises four entries;   the second contiguous plurality of table entries comprises three entries; and   the third contiguous plurality of table entries comprises eight entries.   
     
     
         10 . The radio network node of  claim 6 , wherein the third contiguous plurality of table entries comprises four 64QAM entries and four 256QAM entries. 
     
     
         11 . A radio network node in a wireless network comprising a processor operable to:
 receive a channel quality indicator (CQI) index from a wireless device, wherein the CQI index comprises a four-bit value associated with a channel quality of a wireless signal;   identify an entry in a CQI table based on the CQI index, wherein the CQI table comprises:
 a first contiguous plurality of at least three table entries associated with low SINR and a first modulation coding scheme; and 
 a second contiguous plurality of at least three table entries associated with medium SINR and a second modulation coding scheme; and 
 a third contiguous plurality of table entries associated with high SINR, wherein the third contiguous plurality of table entries comprises a portion of entries associated with a third modulation coding scheme and a portion of entries associated with a fourth modulation coding scheme; and 
   determine a modulation coding scheme based on the identified entry in the CQI table; and   indicate, to the wireless device, the determined modulation coding scheme to be used for downlink data transmission.   
     
     
         12 . The radio network node of  claim 11 , wherein:
 the first sampling grid comprises a grid spacing of approximately 3dB;   the second sampling grid comprises a grid spacing of approximately 2dB; and   the third sampling grid comprises a grid spacing of approximately 2.5dB.   
     
     
         13 . The radio network node of  claim 11 , wherein:
 the first contiguous plurality of table entries comprises Quadrature Phase Shift Keying (QPSK) entries;   the second contiguous plurality of table entries comprises 16 Quadrature Amplitude Modulation (16QAM) entries; and   the third contiguous plurality of table entries comprises 64 Quadrature Amplitude Modulation (64QAM) entries and 256 Quadrature Amplitude Modulation (256QAM) entries.   
     
     
         14 . The radio network node of  claim 11 , wherein:
 the first contiguous plurality of table entries comprises four entries;   the second contiguous plurality of table entries comprises three entries; and   the third contiguous plurality of table entries comprises eight entries.   
     
     
         15 . The radio network node of  claim 11 , wherein the third contiguous plurality of table entries comprises four 64QAM entries and four 256QAM entries. 
     
     
         16 . A wireless device in a wireless network comprising a processor operable to:
 measure a downlink reference signal from a radio network node to produce a signal measurement;   derive a CQI from the signal measurement;   report the CQI to the radio network node with a CQI index that is associated with an entry in a CQI table to assist the radio network node in determining a modulation coding scheme for downlink transmission, wherein the CQI table comprises:
 a first contiguous plurality of at least three table entries associated with low SINR and a first modulation coding scheme; and 
 a second contiguous plurality of at least three table entries associated with medium SINR and a second modulation coding scheme; and 
 a third contiguous plurality of table entries associated with high SINR, wherein the third contiguous plurality of table entries comprises a portion of entries associated with a third modulation coding scheme and a portion of entries associated with a fourth modulation coding scheme; and 
   receive an indication, from the radio network node, of the modulation coding scheme determined by the radio network node for downlink transmission.   
     
     
         17 . The wireless device of  claim 16 , wherein:
 the first contiguous plurality of table entries comprises Quadrature Phase Shift Keying (QPSK) entries;   the second contiguous plurality of table entries comprises 16 Quadrature Amplitude Modulation (16QAM) entries; and   the third contiguous plurality of table entries comprises 64 Quadrature Amplitude Modulation (64QAM) entries and 256 Quadrature Amplitude Modulation (256QAM) entries.   
     
     
         18 . The wireless device of  claim 16 , wherein:
 the first contiguous plurality of table entries comprises four entries;   the second contiguous plurality of table entries comprises three entries; and   the third contiguous plurality of table entries comprises eight entries.   
     
     
         19 . The wireless device of  claim 16 , wherein the third contiguous plurality of table entries comprises four 64QAM entries and four 256QAM entries.