  We study a mm-wave wireless network deployed along the roads of an urban
area, to support localization and communication services simultaneously for
outdoor mobile users. In this network, we propose a mm-wave initial
beam-selection scheme based on localization-bounds, which greatly reduces the
initial access delay as compared to traditional initial access schemes for
standalone mm-wave base station (BS). Then, we introduce a downlink
transmission protocol, in which the radio frames are partitioned into three
phases, namely, initial access, data, and localization, respectively. We
establish a trade-off between the localization and communication performance of
mm-wave systems, and show how enhanced localization can actually improve the
data-communication performance. Our results suggest that dense BS deployments
enable to allocate more resources to the data phase while still maintaining
appreciable localization performance. Furthermore, for the case of sparse
deployments and large beam dictionary size (i.e., with thinner beams), more
resources must be allotted to the localization phase for optimizing the rate
coverage. Based on our results, we provide several system design insights and
dimensioning rules for the network operators that will deploy the first
generation of mm-wave BSs.
