Abstract: A NAT server and a NAT method thereof are provided. The NAT server receives a SIP message including private network RTP information from a user equipment. The NAT server modifies the private network RTP information of the SIP message into public network RTP information and creates in the mapping table a mapping record of the private network RTP information and the public network RTP information. The NAT server transmits the SIP message to a SIP server. The NAT server receives another SIP message from the SIP server, and determines that the public network RTP information of the another SIP message corresponds to the private network RTP information according to the mapping record. The NAT server modifies the public network RTP information of the another SIP message into the private network RTP information and transmits the another SIP message to another user equipment of the private network.

Abstract: A network address translation traversal system and method for real-time communications are provided. The network address translation traversal system includes a user terminal equipment, a network address translation device, a signaling control system and a peer terminal. The user terminal equipment is in a private network, while the signaling control system and the peer terminal are in a public network. The signaling control system is configured to instruct the network address translation device to create a network address translation mapping for a real-time communication connection. The peer terminal is configured to create the real-time communication connection with the user terminal equipment via the network address translation device directly according to the network address translation mapping.

Abstract: A signaling control system for use in a NAT traversal system includes a registrar server and an application layer gateway server. The registrar server is configured to record registration information of two user terminals. The application layer gateway server is configured to determinate whether the two user terminals are located under a same network address translation device according to the registration information during a process where the two user terminals create a session connection, and forward respective session description protocol information of the two user terminals to each other if it is determined that the two user terminals are located under the same network address translation device.

Abstract: A communication network system, a calling terminal and a voice call establishing method thereof are provided. The communication network system comprises a called terminal, the calling terminal and a session initiation protocol (SIP) server. The calling terminal generates and transmits an invite message including IPv4 connection information and IPv6 connection information of the calling terminal. The SIP server is communicatively connected to the calling terminal and the called terminal. The SIP server receives the invite message from the calling terminal and forwards the invite message to the called terminal. The called terminal establishes a voice call with the calling terminal according to one of the IPv4 connection information and the IPv6 connection information of the calling terminal.

Abstract: A transmission system and a transmission method for network address translation traversal are provided. The transmission system includes a private network device, a network address record device, a public network device and a network address translation server. The network address record device records an inner network address of the private network device and an outer network address corresponding to the inner network address. The public network device inquires the inner network address of the private network device and the outer network address corresponding to the inner network address from the network address record device, and generates a packet according to the inner network address and the outer network address corresponding to the inner network address. The network address translation server receives the packet from the public network device, and transmits the packet to the public network device.

Abstract: A transmission system and a transmission method for network address translation traversal are provided. The transmission system includes a private network device, a network address record device, a public network device and a network address translation server. The network address record device records an inner network address of the private network device and an outer network address corresponding to the inner network address. The public network device inquires the inner network address of the private network device and the outer network address corresponding to the inner network address from the network address record device, and generates a packet according to the inner network address and the outer network address corresponding to the inner network address. The network address translation server receives the packet from the public network device, and transmits the packet to the public network device.

Abstract: A network address translation traversal system and method for real-time communications are provided. The network address translation traversal system includes a user terminal equipment, a network address translation device, a signaling control system and a peer terminal. The user terminal equipment is in a private network, while the signaling control system and the peer terminal are in a public network. The signaling control system is configured to instruct the network address translation device to create a network address translation mapping for a real-time communication connection. The peer terminal is configured to create the real-time communication connection with the user terminal equipment via the network address translation device directly according to the network address translation mapping.

Abstract: A method for reducing the handover frequency by a communication device in femtocell networks includes the steps: measuring the radio signal strength by a communication device and storing the information of the serving base station into a cache memory; checking whether the stored information in the cache memory is classified as “femtocell” or not; if so, deleting the macrocell's information from the measurement report by the communication device and transmitting this to the serving base station; when the radio link failure occurred, checking whether the stored information in the cache memory is classified as “femtocell” or not; if so, initiating a timer; detecting an available femtocell before the timer expires; transmitting a call reestablishment request message to the available femtocell for rebuilding the link.

Abstract: A method for reducing the handover frequency by a femto gateway in femtocell networks includes the steps: receiving a measurement report from a communication device by an initial femtocell; transmitting a relocation required message to a femto gateway by the initial femtocell if the signal strength thereof is below a threshold; ignoring the relocation required message and enabling the timer by the femto gateway after receiving the relocation required message; determining whether the cell ID included in the call reestablishment request message is classified as “femtocell” or not by the femto gateway before the timer expires; if so, rebuilding the link to the femtocell in response to the cell ID by the femto gateway.

Abstract: A transmission system and a transmission method for network address translation traversal are provided. The transmission system includes a private network device, a network address record device, a public network device and a network address translation server. The network address record device records an inner network address of the private network device and an outer network address corresponding to the inner network address. The public network device inquires the inner network address of the private network device and the outer network address corresponding to the inner network address from the network address record device, and generates a packet according to the inner network address and the outer network address corresponding to the inner network address. The network address translation server receives the packet from the public network device, and transmits the packet to the public network device.

Abstract: A method for reducing the handover frequency by a femto gateway in femtocell networks includes the steps: receiving a measurement report from a communication device by an initial femtocell; transmitting a relocation required message to a femto gateway by the initial femtocell if the signal strength thereof is below a threshold; ignoring the relocation required message and enabling the timer by the femto gateway after receiving the relocation required message; determining whether the cell ID included in the call reestablishment request message is classified as “femtocell” or not by the femto gateway before the timer expires; if so, rebuilding the link to the femtocell in response to the cell ID by the femto gateway.

Abstract: A method for reducing the handover frequency by a communication device in femtocell networks includes the steps: measuring the radio signal strength by a communication device and storing the information of the serving base station into a cache memory; checking whether the stored information in the cache memory is classified as “femtocell” or not; if so, deleting the macrocell's information from the measurement report by the communication device and transmitting this to the serving base station; when the radio link failure occurred, checking whether the stored information in the cache memory is classified as “femtocell” or not; if so, initiating a timer; detecting an available femtocell before the timer expires; transmitting a call reestablishment request message to the available femtocell for rebuilding the link.

Abstract: A method for a handover procedure comprises detecting a status of a backhaul connection between an original femto base station and a backbone network, and sending a handover request message including a reason code and/or flag to at least one mobile station served by the original femto base station, then the at least one mobile station re-associates with at least one base station other than the original femto base station.