  Limited feedback improves link reliability with a small amount of feedback
from the receiver back to the transmitter. In cellular systems, the performance
of limited feedback will be degraded in the presence of other cell
interference, when the base stations have limited or no coordination. This
paper establishes the degradation in sum rate of users in a cellular system,
due to uncoordinated other cell interference and delay on the feedback channel.
A goodput metric is defined as the rate when the bits are successfully received
at the mobile station, and used to derive an upper bound on the performance of
limited feedback systems with delay. This paper shows that the goodput gained
from having delayed limited feedback decreases doubly exponentially as the
delay increases. The analysis is extended to precoded spatial multiplexing
systems where it is shown that the same upper bound can be used to evaluate the
decay in the achievable sum rate. To reduce the effects of interference, zero
forcing interference cancellation is applied at the receiver, where it is shown
that the effect of the interference on the achievable sum rate can be
suppressed by nulling out the interferer. Numerical results show that the decay
rate of the goodput decreases when the codebook quantization size increases and
when the doppler shift in the channel decreases.
