Can 100 speakers talk for 30-minutes each in one room within one hour and with zero interference to each other ’ s audience ?

While the best known outerbound for the K user interference channel states that there cannot be more than K/2 degrees of freedom, it has been conjectured that in general the constant interference channel with any number of users has only one degree of freedom. In this paper, we provide a toy example (with carefully selected propagation delays) to show how regardless of the number of interfering users K, each user can access 1/2 of the degrees of freedom available to him in the absence of interference. To answer the question in the title, each of the 100 speakers can talk for half the time with no interference to each other’s audience. For the classical interference channel model without delays and with constant channel coefficients randomly drawn from a continuous distribution, we show that the 3 user interference channel with M > 1 antennas at each node almost surely has 3M/2 degrees of freedom.

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