is to control the received Eb/No frequency reuse between cells is used. In this case, the such that the received information can be recovered. inter-cell multiple access is non-orthogonal, regardless of However, in a non-orthogonal multiple-access setting, the intra-cell multiple access, which sets limits on the power control also serves the purpose of controlling the allowable transmission power from a terminal. amount of interference affecting other users. This can be Regardless of whether orthogonal or non-orthogonal expressed as the maximum tolerable interference level at multiple access is used, the same basic scheduling prin- the base station is a shared resource. Even if it, from ciples as for the downlink can be used. A max-C/I a single user's perspective, would be beneficial to trans- scheduler would assign all the uplink resources to the mit at full power to maximize the data rate, this may terminal with the best uplink channel conditions. not be acceptable from an interference perspective as Neglecting any power limitations in the terminal, this other terminals in this case may not be able to would result in the highest capacity (in an isolated cell). CHAPTER 4.5 Scheduling, link adaptation and hybrid ARQ In case of a non-orthogonal multiple-access scheme, channel variations in the time domain could be utilized greedy filling is one possible scheduling strategy. With to improve system performance by applying channel- greedy filling, the terminal with the best radio conditions dependent scheduling, especially in combination with is assigned as high data rate as possible. If the in- dynamic rate control. However, if the scheduler has terference level at the receiver is smaller than the max- access to the frequency domain, for example through the imum tolerable level, the terminal with the second best use of OFDM transmission, scheduling and link adapta- channel conditions is allowed to transmit as well, con- tion can also take place in the frequency domain. tinuing with more and more terminals until the 