  Coordinated base station (BS) transmission has attracted much interest for
its potential to increase the capacity of wireless networks. Yet at the same
time, the achievable sum-rate with single-cell processing (SCP) scales
optimally with the number of users under Rayleigh fading conditions. One may
therefore ask if the value of BS coordination is limited in the many-user
regime from a sum-rate perspective. With this in mind we consider multicell
zero-forcing beamforming (ZFBF) on the downlink of a linear cell-array. We
first identify the beamforming weights and the optimal scheduling policy under
a per-base power constraint. We then compare the number of users m and n
required per-cell to achieve the same mean SINR, after optimal scheduling, with
SCP and ZFBF respectively. Specifically, we show that the ratio m/n grows
logarithmically with n. Finally, we demonstrate that the gain in sum-rate
between ZFBF and SCP is significant for all practical values of number of
users.
