Digest 2012-07-11

- Downlink MU-MIMO = SDMA [Li'09CM]

- Uplink MU-MIMO = collaborative spatial multiplexing (C-SM) [Li'09CM]

- UE must be able to decode the data with a BLER below 10 percent. [Liu'12CM]

- PMI and RI jointly represent the spatial directions of the MIMO channel, while CQI indicates the strength of the corresponding spatial directions. [Liu'12CM]

- PMI and/or CQI may be reported either wide-band or on a subband-specific level (the RI is always reported wideband). [Liu'12CM]

- In scenarios where channel reciprocity is valid (e.g., TDD), the UE transmits a specified pilot also known as a sounding reference signal (SRS) based on which the eNB can estimate the channel. Even in this case, CQI feed-back by the UE is necessary to convey the interference conditions at the UE. These can clearly not be inferred from uplink transmissions. [Liu'12CM]

- Opportunistic scheduling: schedule a transmission, at any scheduling instant, to a user with the best channel condition. [Hur'12TSP]

- There are two main methods for Feedback reduction: feedback rate reduction related to quantization, and feedback number reduction related to reducing the number of parameters being fed back. [Hur'12TSP]

- The resource block size is assumed to be known and can be determined at the medium access control (MAC) layer taking into account the number of users in a system. In practice, it is determined by the standard, for example 12 subcarriers in LTE and 24subcarriers in 802.16e. [Hur'12TSP]

- CQI of user- at block- depends on the diversity technique, the noise variance and channel. [Hur'12TSP]