Identifying modulation and coding schemes and channel quality indicators

#The following relates generally to wireless communication, and more specifically to systems and methods to indicate a modulation and coding scheme (MCS) and a channel quality indicator (CQI) value for a wireless channel for wireless communication systems that support a higher order MCS. Wireless communications systems are widely deployed to provide various types of communication content such as voice, video, packet data, messaging, broadcast, and so on. These systems may be multiple-access systems capable of supporting communication with multiple users by sharing the available system resources (e.g., time, frequency, and power). Examples of such multiple-access systems include code-division multiple access (CDMA) systems, time-division multiple access (TDMA) systems, frequency-division multiple access (FDMA) systems, and orthogonal frequency-division multiple access (OFDMA) systems.

#Generally, a wireless multiple-access communications system may include a number of base stations, each simultaneously supporting communication for multiple mobile devices. Base stations may communicate with mobile devices on downstream and upstream links. Each base station has a coverage range, which may be referred to as the coverage area of the cell. A base station may grant a mobile device resources for upstream transmissions. The grant may be based on CQI data about the downstream channel. The base station and mobile device may access a CQI reporting table and an MCS table to determine the CQI value from the CQI data as well as the MCS to use for a transmission. As wireless communication systems increase their support of additional MCSs, existing CQI tables and MCS tables may not include data entries that account for these additional MCSs that are supported by the communication system.

#The described features generally relate to one or more improved systems, methods, and/or apparatuses for selecting between different modulation and coding scheme (MCS) tables to identify an MCS to use for a transmission as well as selecting between different channel quality indicator (CQI) tables to identify a CQI value about a wireless channel. In one example, the selected MCS table may be used to look-up a size of a transport block that is being transmitted. The various MCS and CQI tables may support modulation schemes up to at least 256 Quadrature Amplitude Modulation (QAM).

#A further understanding of the nature and advantages of the present invention may be realized by reference to the following drawings. In the appended figures, similar components or features may have the same reference label. Further, various components of the same type may be distinguished by following the reference label by a dash and a second label that distinguishes among the similar components. If only the first reference label is used in the specification, the description is applicable to any one of the similar components having the same first reference label irrespective of the second reference label.

#FIG. 1 shows a block diagram of a wireless communications system;

#FIG. 2 is a block diagram illustrating one example of a UE in accordance with the present systems and methods;

#Wireless communication standards may support various modulation and coding schemes for downlink and uplink transmissions. In one configuration, Quadrature Phase Shift Keying (QPSK), 16QAM, and 64QAM may be examples of schemes supported by a wireless communication standard. In one example, five bits may be used to represent an MCS to be used for a transmission. Using a five bit MCS may provide up to 32 possible MCSs to choose from for a transmission. An MCS table based on a five bit MCS may include a list of MCS indices from 0 to 31. Each index may correspond to at least one modulation scheme to be used for a transmission. In addition, each MCS index may be mapped to at least one transport block size (TBS) look-up index. The TBS look-up index may indicate a size of a transport block to be transmitted using the corresponding MCS.

#In addition, a channel quality indicator (CQI) table, may be used to identify a CQI value for a wireless channel. A UE may be configured to report on channel quality using a CQI message. In LTE, both periodic and aperiodic (or event triggered) reporting of CQI is supported. CQI messages may be transmitted on the physical uplink control channel (PUCCH) on the primary component carrier, and not on a secondary component carrier (SCC). Alternatively or additionally, PUCCH may be transmitted on a secondary component carrier when two or more carriers do not have ideal backhaul as part of multi-flow operation or when there is a need to balance PUCCH overhead on different carriers. The CQI value may then be used to select a particular MCS to use for a transmission on the wireless channel. Currently, a CQI value may be represented using a number of bits, such as four bits. A CQI table may include a listing of CQI indices corresponding to the 16 possible CQI values (if four bits are used to represent the CQI value). Each CQI index value may be mapped to additional data that can be used to select an MCS.

#In one example, a wireless communication standard may support schemes up to at least 256QAM. Additional MCS tables and CQI tables may be used to allow for these additional modulation schemes. Devices in a wireless communication system may select an appropriate CQI and MCS table to use to identify a CQI value of a wireless channel and the appropriate MCS to use for a transmission on that wireless channel.