Device for allocating transmission channels to terminals in a service-on-demand system

The invention relates to a device for assigning Transmission channels to terminals of a service-on-demand system according to the preamble of claim 1.

A services-on-demand system, for example, from the journal Electronics 5/1995, pages 50 to 58 known. The services-on-demand system includes a server that is connected via a coupling with a plurality of ATM-HUB is that are themselves of a connected multi-Bont; BONT = Broadband Optical Network Termination. At each BONT are a common coaxial cable connected 64 terminals. to retrieve a service calls for a terminal by means of its set-top box a Connect to the server. The server provides the terminal a Transmission channel ready over which the retrieved serving initially to optical paths until BONT and then to electrical paths to reach the terminal. Typically, for each BONT a certain Number of transmission channels reserved, for example, are the first BONT the transmission channels allocated to 1 to 32, the second BONT the transmission channels 33 to 64, etc .. This is a rigid division that in addition each terminal only the same transmission capacity Provides. This example can only maximum in each group 32 of 64 connected to the terminals simultaneously BONT services recall. In the case of the expansion of the system, for example, by connecting Another set-top boxes to an existing BONT, must the entire system be shut down, for the division of Transmission channels to the terminals and the group re configure.

It is therefore an object of the invention the allocation of Transmission channels to terminals of a service-on-demand system to design such that the above disadvantages do not occur.

This object is in accordance with a device Claim 1 dissolved. The device is in particular characterized in that it between a variable assignment Transmission channels and terminals provides, irrespective of the Group ownership of the terminals. For example, 64 + 64 = 128 terminals, the are divided into two groups on two Bont, 64 Transmission channels provided. The transmission channels are not fixed distributed between the two groups, but largely free for all terminals available. For example, transmission channel 1 through terminal 1 of group 1 and 2 and the transmission channel by terminal 25 from Group 2 is be. To each group a minimum number of freely available to be able to reserve transmission channels, for example, 16 of 64 Transmission channels reserved as the minimum number for group 1 and more 16 of the 64 transmission channels reserved as minimum number of Groups 2. The remaining 32 transmission channels may then, depending on Traffic and demand from both end points of the group 1 as also be used by terminals of the group. 2 This gives Clearances and adapts the allocation of transmission channels automatically to the volume of traffic. An additional advantage is in that each terminal assigned more than one transmission channel can be, thereby expanding the scope, as can Services with different transmission capacity, for example, different image qualities, offered on different charges will.

In one advantageous embodiment of the invention, the minimum number the reserved transmission channels are dynamically varied. This provides the additional advantage of a more flexible allocation of Transmission channels. For example, after commissioning a new or extended system the minimum numbers without changed interruption of the operation and to the current Traffic are matched, whereby an optimum utilization the available transmission capacity can be achieved.

In a further advantageous embodiment of the invention, the Transmission channels are temporarily blocked virtual memory. this has the advantage that also during the event of a failure of one or multiple transmission channels required repair the system remains limited operational, only to be repaired by the Transmission channels are virtually closed and thus are considered occupied.

Further advantageous embodiments of the invention are the dependent refer claims.

An embodiment of the invention will be hereinafter The aid of a figure explained. The figure shows a schematic Representation of a service-on-demand system with an inventive Means for allocating transmission channels.

The services-on-demand system SYS, a so-called service-on-demand System includes a server SER, a management unit VER, a inventive facility EIN for assigning Transmission channels and multiple terminals END1, END2.

The server SER is about setting ON with the plurality of terminals END1, END2 connected via a point-to-multipoint connection. Of the Server SER serves the end user END1, END2 services available deliver. As services are recordable as pay per view, near video on demand, video on demand, telelearning / Teleteaching, Information services, teleshopping or video games available. Of the Users of a terminal END1, END2 selected via a decoder, a so-called set-top box from a service which it then by the server SER is provided, for example by dubbing the retrieved Video film. the server SER requires at least one to dub free transmission channel. The terminal END1; END2 must know which Transmission channel used by the server SER to the dubbed to receive Videeofilm. To assign the transmission channels is the A device used.

The facility EIN for assigning transmission channels to terminals END1, END2 includes at least two interfaces S1, S2 to Connect the device ON with a plurality of terminal END1, END2. Each Interface S1, S2 is on a separate line, for example a Coaxial cable with a group of terminals END1, END2 connected. The interfaces S1 and S2 are respectively the Protocol conversion, as a send unit for transmitting information from the facility EIN to the end user END1, END2 and as Receiving unit for receiving information from the terminals END1, END2.

The facility EIN further includes a memory MEMO, in which a Allocation table is stored. The memory MEMO example a so-called RAM, EEPROM, or a flash. The allocation table contains entries about the currently available and currently occupied Transmission channels for transferring of terminals END1, END2 retrieved services. Thus, a transmission channel is considered, for example, as is when an individual transfer from the server SER to certain terminal END1, END2 is used. Thus, a Transmission channel with a video-on-demand connection exclusively , END2 asked for a specific terminal END1 available to the Terminal END1, END2 operations such as fast forward, fast to allow rewinding or image Stop. In a near-video-on-demand Compound can be a transmission channel by a plurality of terminals END1, END2 be used simultaneously, as only a unidirectional Flow of information from the server SER to the end user END1, END2 takes place. The transmission channel is considered then as long as occupied as long as one of the participating in the service near video-on-demand terminal stations END1, END2 the service in uses, or the transfer is complete.

The mapping table is configured such that a variable assignment between transmission channels and terminals END1, END2 is possible regardless of the group affiliation of the terminal stations. This is a numerical example to clarify: The group 1, which is connected to the S1 interface includes, For example, 10 terminals END1. The group 2 to the interface S2 is connected, for example, includes 10 terminals END2. There are 10 transmission channels provided to the terminals 20 END1, END2 to take care. Because an estimated traffic would 10 Transmission channels are sufficient without leading to shortages, as in usually no more than 50% of the terminals END1, END2 a group simultaneously want to take a repair. Thus, it would sufficient 5 selected transmission channels of group 1 for free allocate available and 5 more transmission channels of the group. 2 Due to statistical tolerances in the estimation of Traffic, the example of an active use Services of terminals END1 the group 1 compared to a restrained use of services of terminals END2 the Group 2 were disregarded, it could happen that 8 of 10 want to take endpoints of Group 1 with a service, while only 2 of the 10 terminals END2 Group 2 this same wanted to. With a fixed assignment of the transmission channels in 5 for Group 1 and 5 in Group 2 as this would not be possible. For this reason is a variable allocation of transmission channels selected, the only 10 freely assignable transmission channels for a total of 20 terminals END1, END2, provides independent of a group membership, so that 8 terminals END1 the group 1 and 2 terminals END2 Group 2 simultaneously can take with a service. In addition to Thus, a terminal END1, END2, more than one Transmission channel, 2 or 3 are assigned the same example.

The facility EIN further includes a control unit CTRL that with is the interfaces S1, S2 and the memory MEMO connected. The Control unit CTRL is for example a processor, for example a so-called DSP or a microprocessor. The control unit CTRL is suitable, Connection requests from individual terminals END1, END2 to to receive polling services. For this purpose, in the control unit CTRL, a Signaling unit provided. The signaling unit detects a emitted from a terminal END1, END2 connection request and then switches a control channel between server SER and terminal END1, END2 free so that the terminal END1, END2 their desired can retrieve service. Thereafter, the control unit CTRL of the terminal END1, END2 least one transmission channel to selected from the available in the memory MEMO and the number adapted to the retrieved serving. The terminal END1, END2 can then retrieved Service on the person or zugwiesenen transmission channels available be provided. In addition, the one or more assigned Transmission channels in the memory MEMO recorded as occupied.

can only be assigned transmission channels in memory MEMO are available currently. Are all transmission channels in Memory MEMO as busy, so will the individual terminals END1, END2 are received from the control unit CTRL that currently a Connection setup is not possible. The control unit CTRL can for example, be programmed so that they after a Communication a terminal END1, END2, if a connection is not possible is, the memory MEMO monitored and the appropriate terminal END1, END2 informed as soon as a transmission channel is considered unoccupied and available again.

The control unit CTRL is adapted to allocate the transmission channels carry out such that one for each group of terminals END1, END2 of assignable transmission channels does not fall below the minimum value and not to exceed a maximum value of assignable transmission channels is, with minimum and maximum values ​​are not equal. A numerical example illustrates this: The Group 1, at the interface S1 is connected, for example, includes 30 terminals END1. The Group 2, which is connected to the interface S2 includes, For example, 30 terminals END2. There are 30 transmission channels provided to supply the 60 terminals END1, END2. 10 of 30 Transmission channels are kept free, so that they for the terminals END1 Group 1 freely available. 10 more of the 30 Transmission channels are kept free, so that they for the terminals END2 Group 2 for free available. It does not matter which the 30 transmission channels are kept clear, important is their Absolute number. The absolute number 10 represents the minimum value in the Initialization of the system SYS can be input into the control unit CTRL. The remaining 10 transmission channels can then both of terminals END1 of Group 1 and Group 2 of terminals END2 of used be such that a maximum of 20 transmission channels for each Group results. The maximum value, in the initialization of the system SYS are input to the control unit CTRL, for example, manually via a Keyboard. In the event that a group of terminal stations END1; END2 more transmission channels are required than the maximum value are given, for example 21 instead of 20, and at the same time but only For example, 5 of the 10 transmission channels for the other group are provided are occupied, the requested transmission channel 21 applies for the first group as occupied, although still 5 transmission channels for free available, but only for the second group, so that they are locked for the first group. For each group of terminals END1; END2 is always a minimum number of transmission channels at leisure, in the example 10th

The control unit CTRL can be programmed, for example such, that it is capable, the minimum values ​​and / or the maximum values dynamically change; For example, according to the control unit CTRL the initialization monitored actual traffic and the minimum values ​​and the maximum values ​​are adapted. The dynamsiche changes the minimum values ​​and the maximum values carried out without interrupting the operation, for example by means of a Keyboard software technology, the values ​​to be programmed or the CRTL control unit is programmed so as to adapt the performs automatically. The latter is for example realized by the control unit over a fixed period, eg one week, always the Number of simultaneously occupied by a group of transmission channels recorded, and then the maximum number of occurrences Assignments new sets as the minimum value for the respective group.

Further, the control unit CTRL can be programmed so that it is suitable for individual transmission channels or groups of temporarily to block transmission channels in the memory MEMO virtually so that these transmission channels are considered busy. This has the advantage that not all as in the case of repair of a transmission channel System must be shut down, but only to be repaired Transmission channel for all terminals END1, END2 or for a group of terminals for the duration of the repair is not available. The Terminals END1, END2 are so during a repair of a Transmission channel such as 19 of the 20 transmission channels continue to Available. Through virtual lock and unlock can transfer channels in a simple manner the capacity of a certain number of terminals END1, END2 available transmission channels are varied. If the system eg extended, for example, by connecting additional terminals END1, END2 or further by making available, may Transmission capacity intensive services, so the number of Transmission channels at the then had grown traffic be adjusted by additionally provided transmission channels will be released and thus the terminals END1, END2 to Use of services available.

The system SYS may further comprise a management unit VER. The management unit VER includes, for example, a processor, by means of which they traffic levels throughout the system SYS monitored. So the system has, for example, a plurality of means for ON Allocating transmission channels each with the central server SER and the central management unit VER are connected. To this Way it is monitoring functions in the management unit VER centralize, what a saving of technical effort accompanied. Managing the system SYS is usually as Management or network management respectively. Thus, the Management unit, for example, to monitor the functioning of the transmission channels by, for example, test measurements on blank take over transmission channels and the device then the ON Statement transmit individual transmission channels virtually lock, if this example are faulty and repair is necessary. The A device includes for this purpose an interface S3 to Management unit VER. The control unit CTRL is with this interface S3 connected and as appropriate, through this interface S3 Information to receive about which to terminate the transmission channels virtually are. The interface S3 is used for protocol conversion, as a send unit Transmitting information from the facility EIN for Management unit VER and a receiving unit for receiving Information from the management unit VER.

The control unit CTRL can be adapted via the interface S3, the to receive information which minimum values ​​and which maximum values to apply to that group of terminals END1, END2. For example, oversees the management unit VER the current traffic and thereby determines those minimum and maximum values ​​that a exploit predetermined transmission capacity in an optimal and Terminals END1, END2 provide maximum service.

The terminals END1, END2 should have the opportunity with connections be able to produce a selectable number of transmission channels retrieve or services for the provision of a different Number of transmission channels is required. The control unit CTRL is programmed for this purpose such that it is suitable, for example, from the connection request of individual terminals END1, END2 a corresponding number of requested transmission channels to detect and the respective terminal END1, END2 the detected number of transmission channels for the duration of the mobilization of the assign each service.

When setting ON for allocating transmission channels is a Interface S4 to the server SER provided. The control unit CTRL is with this interface connected S4 and suitable, the information which Transmission channels it has assigned to each terminal END1, END2 to be transmitted via the interface S4 to the server SER, so that the server SER knows which transmission channel it to the retrieved serving to make available. The interface S4 is the protocol conversion, as Transmitter unit for transmitting information from the device A to the server SER and as a receiving unit for receiving information from the server SER. The device may also, before the allocation of contact transmission channels to the server SER in contact For example, the server SER to ask how much transmission channels for one retrieved from a terminal END1, END2 service needs will.

In the embodiment, the system SYS is a purely electric. The Invention can also be a hybrid glass fiber / coaxial cable system be applied. For this, the device is for example in the server SER disposed and the interface S1 includes an electrical / optical converter, with the facility EIN via a HUB and several Bont a plurality of terminals to connect END1.