Systems and methods for modulation and coding scheme selection and configuration

Abstract

A mobile communication device includes a table component, a table selection component, a control information component, and a communication component. The table component is configured to maintain two or more tables each having entries for a plurality of available modulation schemes. The table selection component is configured to select a selected table from one of the default table and the secondary table based on one or more of RRC layer signaling and MAC layer signaling and further based based on a control information format for control information received from the eNB. The control information component is configured to receive control information indicating a modulation and coding scheme from the selected table, and the communication component is configured to receive and process a communication from the eNB based on the modulation and coding scheme from the selected table.

1 . A user equipment (UE) comprising:
 a table component configured to maintain two or more tables each having entries for a plurality of available modulation schemes, the two or more tables comprising a default table and a secondary table, wherein the default table and the secondary table have a same number of entries, and wherein the secondary table comprises an entry corresponding to a 256-quadrature amplitude modulation (QAM) scheme;   a table selection component configured to select a selected table from one of the default table and the secondary table, wherein the table selection component is configured to use the default table as a default and select the secondary table in response to messaging from an Evolved Universal Terrestrial Radio Access Network (E-UTRAN) Node B (eNB) indicating selection of the secondary table, wherein the messaging comprises one or more of radio resource control (RRC) layer signaling and medium access control (MAC) layer signaling, and wherein the table selection component is further configured to select the default table based on a control information format for control information received from the eNB;   a control information component configured to receive control information indicating a modulation and coding scheme from the selected table; and   a communication component configured to receive and process a communication from the eNB based on the modulation and coding scheme from the selected table.   
     
     
         2 . The UE of  claim 1 , wherein the table selection component is configured to select the default table in response to the control information format comprising downlink control information (DCI) format 1A. 
     
     
         3 . The UE of  claim 1 , wherein the table selection component is further configured to select the default table in response to a handover to a target cell. 
     
     
         4 . The UE of  claim 1 , wherein the UE comprises a soft buffer comprising a 256-QAM soft buffer size, the UE further comprising a soft buffer size component configured to use a soft buffer size less than the 256-QAM soft buffer size until an indication from the eNB to use the 256-QAM soft buffer size is received. 
     
     
         5 . The UE of  claim 4 , wherein the indication from the eNB comprises RRC or MAC layer signaling. 
     
     
         6 . The UE of  claim 1 , wherein the default table and secondary table each comprise a modulation and coding scheme table used to select a modulation order and transport block size based on a modulation and coding scheme index, wherein the secondary table is for selective use in place of the default table. 
     
     
         7 . The UE of  claim 1 , wherein the default table comprises a default modulation and coding scheme table and the secondary table comprises a secondary modulation and coding scheme table, wherein the table component is further configured to maintain a default channel quality indicator table and a secondary channel quality indicator table, and wherein the table selection component is further configured to select a plurality of selected tables comprising:
 selecting one of the default modulation and coding scheme table and the secondary modulation and coding scheme table; and   selecting one of the default channel quality indicator table and the secondary channel quality indicator table.   
     
     
         8 . A mobile communication device configured to:
 maintain two or more modulation sets each having entries for a plurality of available modulation schemes, the two or more modulation sets comprising a first modulation set and a second modulation set, wherein the first modulation set and the second modulation set comprise one or more shared entries and one or more unshared entries, and wherein the unshared entries are indexed in an ascending or descending order relative to each other;   select the second modulation set based on signaling from a base station;   estimate a first channel and second channel between the mobile communication device and the base station; and   send to the base station an index value indicating a quality of the first channel and a differential index value indicating a quality of the second channel, wherein the differential index value comprises a value based on the second table arranged in order according to one or more of a modulation value and a transport block size index in the selected table.   
     
     
         9 . The mobile communication device of  claim 8 , wherein the first modulation set and second modulation set each comprise a channel quality indicator modulation set used to indicate a modulation and coding rate preferred by the UE based on a channel quality indicator index, and wherein the second modulation set is for selective use in place of the first modulation set. 
     
     
         10 . The mobile communication device of  claim 8 , wherein one or more of:
 the first channel and second channel are different spatial streams; and   first channel corresponds to a wide frequency band and the second channel corresponds to a sub-frequency band of the wide frequency band.   
     
     
         11 . The mobile communication device of  claim 8 , wherein the differential index value comprises an offset value in relation to the index value. 
     
     
         12 . The mobile communication device of  claim 8 , wherein the one or more shared entries have the same index values in the first modulation set and the second modulation set. 
     
     
         13 . An Evolved Universal Terrestrial Radio Access Network (E-UTRAN) Node B (eNB) comprising:
 a table configuration component configured to configure two or more tables at a user equipment (UE) each having entries for a plurality of available modulation schemes, the two or more tables comprising a first table and a second table and a same number of entries with respect to one another, wherein the first table and the second table comprise one or more shared entries and one or more unshared entries, wherein the one or more shared entries have a same table index value in the first table and the second table, and wherein an unshared entry of the second table comprises an entry corresponding to a modulation scheme having a higher order modulation than a highest-order modulation scheme of the first table;   a capability component configured to determine that the UE is capable of the modulation scheme having the higher order modulation, wherein the eNB is in communication with the UE in a small cell;   an ambiguity component configured to determine an ambiguity period table index value that corresponds to a shared entry for use during an ambiguity period; and   a control component configured to send a signal to the UE indicating which of the first table and the second table are selected and to further send, during the ambiguity period, a signal to the UE indicating the ambiguity period table index value.   
     
     
         14 . The eNB of  claim 13 , wherein the ambiguity period comprises a period between the eNB sending a signal indicating the selected table to the UE and the eNB receiving a signal from the UE indicating that the UE received the signal indicating the selected table. 
     
     
         15 . The eNB of  claim 13 , wherein the first table and second table each comprise a channel quality indicator table used to indicate a modulation and coding rate preferred by the UE based on a channel quality indicator index, and wherein the second table is for selective use in place of the first table. 
     
     
         16 . The eNB of  claim 15 , further comprising:
 a channel estimator component configured to receive the channel quality indicator index indicating a preferred modulation and coding rate based on the channel between the eNB and the UE; and   a modulation and coding scheme component configured to select the ambiguity period table index value based on the channel quality indicator index received from the UE.   
     
     
         17 . The eNB of  claim 13 , wherein the control component is configured to send signaling to the UE comprising an indication enabling use of a 256-QAM soft buffer size. 
     
     
         18 . The eNB of  claim 17 , wherein the indication enabling use of a 256-QAM soft buffer size comprises one or more of radio resource control (RRC) and medium access control (MAC) layer signaling. 
     
     
         19 . The eNB of  claim 13 , wherein the first table and second table each comprise a modulation and coding scheme table used to select a modulation order and transport block size based on a modulation and coding scheme index, wherein the second table is for selective use in place of the first table. 
     
     
         20 . The eNB of  claim 13 , wherein the first table comprises a first modulation and coding scheme table and the second table comprises a second modulation and coding scheme table, wherein the table component is further configured to maintain a first channel quality indicator table and a second channel quality indicator table, and wherein the table selection component is further configured to select a plurality of selected tables comprising:
 selecting one of the default modulation and coding scheme table and the secondary modulation and coding scheme table; and   selecting one of the default channel quality indicator table and the secondary channel quality indicator table.