A method for wireless communications, the method comprising: broadcasting, by a controller, information of a first preamble and information of a second preamble for a random access procedure; transmitting, by the controller, control information in response to receiving a random access message transmitted by a user equipment, UE, in the random access procedure, the control information being carried in resources of a common search space, wherein the common search space is a first common search space in response to the random access message comprising a preamble corresponding to the first preamble, and the common search space is a second common search space in response to the random access message comprising a preamble corresponding to the second preamble; transmitting, by the controller to the UE, configuration information of a user specific search space for the UE in response to the random access message comprising the preamble corresponding to the first preamble, the configuration information for the user specific search space being scheduled in the first common search space; and scheduling, by the controller, communications with the UE using the user specific search space; and wherein the method further comprises: scheduling, by the controller, a response message in response to receiving the random access message in resources of the common search space; and receiving, by the controller from the UE, identification information of the UE; and transmitting, by the controller to the UE, an indicator indicating a search space configuration in a set of search space configurations, the search space configuration comprising the user specific search space. broadcasting, by a controller, information of a first preamble and information of a second preamble for a random access procedure; transmitting, by the controller, control information in response to receiving a random access message transmitted by a user equipment, UE, in the random access procedure, the control information being carried in resources of a common search space, wherein the common search space is a first common search space in response to the random access message comprising a preamble corresponding to the first preamble, and the common search space is a second common search space in response to the random access message comprising a preamble corresponding to the second preamble; transmitting, by the controller to the UE, configuration information of a user specific search space for the UE in response to the random access message comprising the preamble corresponding to the first preamble, the configuration information for the user specific search space being scheduled in the first common search space; and scheduling, by the controller, communications with the UE using the user specific search space; and wherein the method further comprises: scheduling, by the controller, a response message in response to receiving the random access message in resources of the common search space; and receiving, by the controller from the UE, identification information of the UE; and transmitting, by the controller to the UE, an indicator indicating a search space configuration in a set of search space configurations, the search space configuration comprising the user specific search space. scheduling, by the controller, a response message in response to receiving the random access message in resources of the common search space; and receiving, by the controller from the UE, identification information of the UE; and transmitting, by the controller to the UE, an indicator indicating a search space configuration in a set of search space configurations, the search space configuration comprising the user specific search space.