VOIP bandwidth management system and method thereof

A bandwidth management system and a method adapted for the system. The system determines when the sum of the required bandwidth of a new VOIP call and previous VOIP calls from a client device is greater than the maximum sustained rate, transmits a SIP invite to a called party of the new VOIP call to execute a SIP negotiation via a base station and monitors the new VOIP call and the VOIP calls whose SIP negotiations are not successful. When one of the VOIP calls of awaiting SIP negotiations is successful, the system calculates an actual used bandwidth of the client device, and when the actual used bandwidth is equal to or less than the maximum sustained rate, the system establishes a call link for the one VOIP call and monitoring the other VOIP calls of awaiting SIP negotiations.

BACKGROUND

1. Technical Field

The disclosure generally relates to bandwidth management systems, particularly to a bandwidth management system and a bandwidth management method adapted for the system based on the voice over Internet protocol (VOIP).

2. Description of the Related Art

In worldwide interoperability for microwave access (WIMAX), VOIP techniques are very significant. Customer premises equipment (CPE) of the WIMAX system may synchronously establish several VOIP calls. Before establishing a new VOIP call, the CPE needs to obtain a large bandwidth from a base station of the WIMAX system. When determining codec used by the new VOIP call, the CPE updates an actual used bandwidth of the new VOIP call. However, when the CPE synchronously establishes several VOIP calls or there is no time to update the actual used bandwidth of one or more of the several VOIP calls, the sum of required bandwidth of the several VOIP calls will be greater than the maximum bandwidth threshold allowed by the base station of the WIMAX system. Therefore, establishing a new VOIP call will take up more bandwidth than what would be the actually used bandwidth for the new VOIP call, leading that it is hard to establish the new VOIP call due to irrational allocation of bandwidth resources.

Therefore, what is needed is a bandwidth management system to overcome the described shortcoming.

DETAILED DESCRIPTION

FIGS. 1 and 2are a WIMAX network1of an exemplary embodiment. The WIMAX network1includes at least one base station10, a dynamic host configuration protocol server (DHCP)20, a plurality of client devices30, and an element management system (EMS)40. The client device30is operable to communicate with at least one telephone200. The client device30includes a bandwidth management system31, a storage32, a processor33, and a communication unit34. The bandwidth management system31is used to manage bandwidth of all VOIP calls of the client device30according to running conditions of the WIMAX network1before establishing a new VOIP call, thereby reasonably utilizing bandwidth resources to establish more new VOIP calls. The storage32stores data, for example, the profile of each base station10. The processor33processes data and controls the bandwidth management system31to work. The communication unit34receives and sends wireless signals. The bandwidth management system31may include computerized instructions in the form of one or more programs that are stored in the storage32, and executed by the processor33to provide functions of the client device30.

The client device30establishes a dual communication with the base station10via the communication unit34, and further communicates with the DHCP20and the EMS40through the base station10. The base station10, the DHCP20, and the EMS40communicate with each other via a network, such as the Internet.

The base station10is capable of communicating with the client devices30located within signal coverage areas of the base station, and processing inquiring commands sent from the EMS40. The inquiring commands are used to inquire a base station identity code (BSID), frequencies, bandwidth, a carrier to interference plus noise ratio (CINR), and a client capacity usage of the WIMAX system. Additionally, the base station10is capable of sending processed results of the inquiring commands back to the EMS40.

The DHCP20is capable of getting an internet protocol (IP) address or a fully qualified domain name (FQDN) of the EMS40via a network, and distributing a new IP address to the client devices30when receiving DHCP request signals sent from the corresponding client devices30. The DHCP20is also capable of transmitting the IP address or the FQDN of the EMS40to the client devices30.

The client device30is capable of getting available WIMAX channels of the base station10through scanning operation frequency (e.g., 2.3 GHz or 2.5 GHz), and connecting to the available WIMAX channels in order according to the CINR of the available WIMAX channels. In this exemplary embodiment, the available WIMAX channels can be three channels with greater CINR. The client device30connects to the available WIMAX channel with greatest CINR by default, and other available WIMAX channels are regarded as spare channels. In this exemplary embodiment, the CINR difference between the connected channel and the spare channels is less than 3 dB. When the client device30communicates with the base station10, the client device30can send the DHCP request signals to the DHCP20through the base station10to request the DHCP20to distribute the new IP address. Meanwhile, when distributing the IP address to the client device30, the DHCP20sends the IP address of the EMS40to the client device30. When the client device30gets the new IP address distributed by the DHCP20and the IP address or the FQDN of the EMS40, the client device30can exchange authentication information with the EMS40so that the client device30can download bootstrap programs from the EMS40, and then communicate with EMS40.

The bandwidth management system31includes a number of modules which are to be executed by the processor33. As shown inFIG. 3, the number of modules include a trap request sending module310, a maximum sustained rate receiving module320, a call request sending module330, a bandwidth determination module340, a call control module350, and a bandwidth calculating module360.

In case of establishing a communication connection between the client device30and the EMS40, the trap request sending module310controls the communication unit34to send a predefined trap message to the EMS40in order to request the EMS40to search the maximum sustained rate set by service flow of unsolicited granted service (UGS) or extended real-time polling service (ERTPS) of a sector of the base station10via the base station10. Meanwhile, the EMS40responds to the predefined trap message to acquire the maximum sustained rate from the base station10and sends the maximum sustained rate to the client device30.

The maximum sustained rate receiving module320receives the maximum sustained rate from the EMS40via the communication unit34and stores the maximum sustained rate in the storage32. Before the client device30establishes a new VOIP call, the call request sending module330controls the communication unit34to send a new VOIP call request to the base station10and determines a required bandwidth of a new VOIP call.

The bandwidth determination module340determines whether the sum of the required bandwidth of the new VOIP call and previous VOIP calls from the client device30is greater than the maximum sustained rate. The previous VOIP calls include calls which are busy and calls whose session initiation protocol (SIP) negotiations are not successful. When the sum of the required bandwidth of the new VOIP call and the previous VOIP calls is less than the maximum sustained rate, that means that current bandwidth of the base station10is enough, the call control module350successfully establishes the new VOIP call based on a normal process. The normal process is described as follows: the client device30transmits an uplink dynamic service addition request (DSA-REQ) to the base station10and receives an uplink dynamic service addition response (DSA-RSP) from the base station10, thereby establishing an uplink service flow; the client device30further transmits a downlink DSA-REQ to the base station10and receives a downlink dynamic service addition response (DSA-RSP) from the base station10, thereby establishing a downlink service flow; the client device30transmits a SIP invite to a called party of the new VOIP call to execute a SIP negotiation via the base station10; and when the client device30receives a predefined signal from the called party via the base station10, such as a 200 OK signal, the SIP negotiation of the new VOIP call is successful, that means that the new VOIP call is successfully established.

When the sum of the required bandwidth of the new VOIP call and the previous VOIP calls is equal to or greater than the maximum sustained rate, that means that current bandwidth of the base station10is too narrow, the call control module350directly transmits the SIP invite to the called party to execute the SIP negotiation of the new VOIP call via the base station10and activates a bandwidth management process to monitor the new VOIP call and the VOIP calls whose SIP negotiations are not successful. It is obvious that both the new VOIP call the VOIP calls whose SIP negotiations are awaiting.

The bandwidth management process is described as follows: when the bandwidth determination module340determines one of the VOIP calls of awaiting SIP negotiations is successful, the bandwidth calculating module360calculates an actual used bandwidth of the client device30; when the actual used bandwidth is greater than the maximum sustained rate, the call control module350terminates all the VOIP calls of awaiting SIP negotiations.

When the actual used bandwidth is equal to or less than the maximum sustained rate, the call control module350establishes a call link for the one of the VOIP calls of awaiting SIP negotiations and the bandwidth management system31continues to monitor the other VOIP calls of awaiting SIP negotiations. When all the VOIP calls of awaiting SIP negotiations do not exist, that means that all the VOIP calls of awaiting SIP negotiations were successful or all the VOIP calls of awaiting SIP negotiations were terminated, the bandwidth calculating module360calculates the actual used bandwidth of the client device30based on dynamic service change (DSC).

FIGS. 4A-4Bshow a bandwidth management method according to an exemplary embodiment. The bandwidth management method can use the aforementioned bandwidth management system31and may at least include the following steps.

In step S1, the client device30scans the operation frequency in use to get the available WIMAX channels, and then connects to the available WIMAX channel with the largest CINR.

In step S2, the client device30transmits DHCP request signals to the DHCP20through the base station10, and the DHCP20distributes a new IP address to the client device30; and then transmits the IP address or the FQDN of the EMS40to the client device30.

In step S3, the client device30begins to initialize, exchanges the authentication information with the EMS40and downloads the bootstrap programs from the EMS40, and then analyzes and updates the bootstrap programs. Thus, the client device30can upload the bootstrap programs to the EMS40to communicate with the EMS40.

In step S4, the trap request sending module310controls the communication unit34to send a predefined trap message to the EMS40in order to request the EMS40to search the maximum sustained rate set by service flow of unsolicited granted service (UGS) or extended real-time polling service (ERTPS) of a sector of the base station10via the base station10.

In step S5, the maximum sustained rate receiving module320receives the maximum sustained rate from the EMS40via the communication unit34and stores the maximum sustained rate in the storage32.

In step S6, before the client device30establishes a new VOIP call, the call request sending module330controls the communication unit34to send a new VOIP call request to the base station10and determines a required bandwidth of a new VOIP call.

In step S7, the bandwidth determination module340determines whether the sum of the required bandwidth of the new VOIP call and previous VOIP calls from the client device30is greater than the maximum sustained rate.

In step S8, when the sum of the required bandwidth of the new VOIP call and the previous VOIP calls is less than the maximum sustained rate, the call control module350establishes the new VOIP call.

In step S9, when the sum of the required bandwidth of the new VOIP call and the previous VOIP calls is equal to or greater than the maximum sustained rate, the call control module350transmits the SIP invite to the called party to execute the SIP negotiation of the new VOIP call via the base station10and monitors the new VOIP call and the VOIP calls whose SIP negotiations are not successful.

In step S10, when the bandwidth determination module340determines that one of the VOIP calls of awaiting SIP negotiations is successful, the bandwidth calculating module360calculates an actual used bandwidth of the client device30.

In step S11, the bandwidth determination module340determines whether the actual used bandwidth is greater than the maximum sustained rate.

In step S12, when the actual used bandwidth is equal to or less than the maximum sustained rate, the call control module350establishes a call link for the one of the VOIP calls of awaiting SIP negotiations and continues to monitor the other VOIP calls of awaiting SIP negotiations, the procedure returns the step S9.

In step S13, when the actual used bandwidth is greater than the maximum sustained rate, the call control module350terminates all the VOIP calls of awaiting SIP negotiations.

In step S14, when all the VOIP calls of awaiting SIP negotiations do not exist, the bandwidth calculating module360calculates the actual used bandwidth of the client device30based on dynamic service change (DSC).