Degrees-of-freedom based on interference alignment with imperfect channel knowledge

Won Yong Shin, Muryong Kim, Hyoseok Yi, Ajung Kim, Bang Chul Jung

Research output: Contribution to journalArticlepeer-review

9 Citations (Scopus)


The impact and benefits of channel state information (CSI) are analyzed in terms of degrees-of-freedom (DoFs) in a K-user interference network operating over time-selective channels, where the error variance of CSI estimation is assumed to scale with an exponent of the received signal-to-noise ratio (SNR). The original interference alignment (IA) scheme is used with a slight modification in the network. Then, it is shown that the DoFs promised by the original IA can be fully achieved under the condition that the CSI quality order, represented as a function of the error variance and the SNR, is greater than or equal to 1. Our result is extended to the case where the number of communication pairs, K, scales with the SNR, i.e., infinite K scenario, by introducing the user scaling order. As a result, this letter provides vital information to the system designer in terms of allocating training resources for channel estimation in practical cellular environments using IA.

Original languageEnglish
Pages (from-to)3579-3582
Number of pages4
JournalIEICE Transactions on Communications
Issue number12
Publication statusPublished - 2011 Dec

All Science Journal Classification (ASJC) codes

  • Software
  • Computer Networks and Communications
  • Electrical and Electronic Engineering


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