Mechanisms for wireless directional transmission systems are proposed. In a first novel aspect, a mechanism for reference signal provisioning and channel information reporting is proposed. Two sets of measurement pilots are introduced for initial access and control signaling. In a second novel aspect, a beamwidth adaptation mechanism is proposed to deal with occasional channel variation without requiring constantly high overhead due to measurement pilot transmission. In a third novel aspect, a mechanism for backhaul link to activate/deactivate efficiently is proposed. New states of activated state and deactivated state are introduced.