An Evaluation of LTE Frequency Selective Scheduling

Guest post by Faris Alfarhan*

Frequency selective scheduling

Channel dependent scheduling is commonly used in cellular systems. In LTE, orthogonal frequency division multiple access (OFDMA) in the downlink and single carrier frequency division multiple access (SC-FDMA) in the uplink allow scheduling to be performed orthogonally in both the frequency and time domains. Instead of exploiting the frequency diversity of the channel, frequency-selective scheduling leverages the channel’s time and frequency selectivity to allocate valuable radio resources in an optimal manner. The OFDMA and SC-FDMA shared channel transmissions incorporated in LTE offer great flexibility for integrating adaptive scheduling strategies. The minimum resource allocation corresponds to a resource block of 180 kHz and a time duration of 0.5 ms. Downlink resource allocation relies on the channel quality index (CQI) reported by the user. For frequency selective scheduling to be applicable, the CQI must be reported for all of the carrier’s resource blocks. Read more of this post