The present specification discloses a mobile communication system. More particularly, the present disclosure relates to a method and an apparatus for transmitting and receiving data using a plurality of carriers in a mobile communication system.

In a system where a first node provides a first area of TDD coverage on a first TDD carrier using a first TDD configuration and an adjacent second node provides a second area of TDD coverage on a second TDD carrier using a different second TDD configuration, the first node could additionally provide an area of FDD coverage on a first FDD carrier, including causing the area of FDD coverage to sit at least partially between the first and second areas of TDD coverage and therefore to define a spatial buffer between the first and second areas of TDD coverage. For instance, the first access node could restrict its service on the first TDD carrier to be for user equipment devices (UEs) that are relatively close to the first access node and could restrict its service on the first FDD carrier to be for UEs that are relatively far away from the first access node.

In a system where a first node provides a first area of TDD coverage on a first TDD carrier using a first TDD configuration and an adjacent second node provides a second area of TDD coverage on a second TDD carrier using a different second TDD configuration, the first node could additionally provide an area of FDD coverage on a first FDD carrier, including causing the area of FDD coverage to sit at least partially between the first and second areas of TDD coverage and therefore to define a spatial buffer between the first and second areas of TDD coverage. For instance, the first access node could restrict its service on the first TDD carrier to be for user equipment devices (UEs) that are relatively close to the first access node and could restrict its service on the first FDD carrier to be for UEs that are relatively far away from the first access node.

A method for hotspot detection includes: computing, by a device, a ratio of a local user density within a first distance zone of a user density map towards a hotspot center point candidate to a local user density within a second distance zone of the user density map towards the same hotspot center point candidate; if the computed ratio exceeds a threshold, assigning, by the device, particular candidate points of the user density map within a certain distance to the hotspot center point candidate to a hotspot, the hotspot representing a concentrated conglomeration of users of the mobile communication network; and detecting, by the device, a center point of the hotspot based on the particular candidate points assigned to the hotspot.

A method for hotspot detection includes: computing, by a device, a ratio of a local user density within a first distance zone of a user density map towards a hotspot center point candidate to a local user density within a second distance zone of the user density map towards the same hotspot center point candidate; if the computed ratio exceeds a threshold, assigning, by the device, particular candidate points of the user density map within a certain distance to the hotspot center point candidate to a hotspot, the hotspot representing a concentrated conglomeration of users of the mobile communication network; and detecting, by the device, a center point of the hotspot based on the particular candidate points assigned to the hotspot.

A communications method and device for multi-carrier aggregation, where the method includes: grouping by a base station, N serving cells into K cell groups, where N is an integer greater than zero, and K is an integer less than N, sending, by the base station, a cell grouping message to user equipment (UE), where the cell grouping message indicates that the N serving cells are grouped into the K cell groups, and communicating, by the base station, with the UE according to the K cell groups. Hence, signaling overheads can be reduced.

A communications method and device for multi-carrier aggregation, where the method includes: grouping by a base station, N serving cells into K cell groups, where N is an integer greater than zero, and K is an integer less than N, sending, by the base station, a cell grouping message to user equipment (UE), where the cell grouping message indicates that the N serving cells are grouped into the K cell groups, and communicating, by the base station, with the UE according to the K cell groups. Hence, signaling overheads can be reduced.

Methods, systems, and devices for wireless communications are described. The method includes establishing a first component carrier as a primary cell for the user equipment (UE) and a second component carrier as a secondary cell for the UE, receiving primary cell configuration information for the second component carrier while the second component carrier is the secondary cell for the UE, receiving a control message triggering a switch of the primary cell from the first component carrier to the second component carrier, and establishing the second component carrier as the primary cell for the UE based on the control message and in accordance with the primary cell configuration information associated with the second component carrier.

Methods, systems, and devices for wireless communications are described. The method includes establishing a first component carrier as a primary cell for the user equipment (UE) and a second component carrier as a secondary cell for the UE, receiving primary cell configuration information for the second component carrier while the second component carrier is the secondary cell for the UE, receiving a control message triggering a switch of the primary cell from the first component carrier to the second component carrier, and establishing the second component carrier as the primary cell for the UE based on the control message and in accordance with the primary cell configuration information associated with the second component carrier.

A method for establishing a small cell telecommunications network is provided. The method includes determining a plurality of sets of candidate locations, in which each set includes candidate locations for establishing small cell base transceiver stations to provide wireless network service. Each location in the set is determined by applying a gradient descent process to find a local optimal location. The evaluation criteria in the process can include, e.g., an estimated number of people expected to receive coverage, and/or the cost of operating the base transceiver stations. The plurality of sets are evaluated to determine a set of global optimal locations. The evaluation criteria can include, e.g., the expected revenue generated per unit time minus the cost of operating the base transceiver stations per unit time.