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 is known for example from the magazine Elektronik 5/1995, pages 50 to 58th The services-on-demand system includes a server, which is connected via an ATM connection with several HUBs that are connected to multiple Bont themselves of a; BONT = Broadband Optical Network Termination. At each BONT 64 terminals are connected via a common coaxial cable. To retrieve a service calls for a terminal by means of its set-top box to establish a connection to the server. The server provides the terminal a transmission channel ready first then passes through which the retrieved serving on optical paths until BONT and electrical paths to the terminal. Usually a certain number of transmission channels for each BONT reserved, for example, the transmission channels 1 to 32 are the first BONT assigned, the second BONT the transmission channels 33 to 64, etc .. This is a rigid division, which in addition each terminal only the same transmission capacity provides. This example can only a maximum of 32 of the 64 connected to the terminals BONT call services at the same time in each group. In the case of the expansion of the system, for example, by connecting additional set-top boxes to an existing BONT, the entire system must be shut down to configure the allocation of transmission channels to the terminals and the new groups.

It is therefore services on-demand system to make the allocation of transmission channels to terminals of such an object of the invention that the above does not occur disadvantages.

According to the invention this object is achieved by a device according to claim. 1 The device is in particular characterized in that it provides for a variable assignment between transmission channels and terminals, regardless of the group affiliation of the terminal stations. For example, 64 + 64 = 128 terminal stations, which are distributed in two groups on two BoNTs, 64 transmission channels are provided. The transmission channels are not permanently allocated to the two groups, but largely for all terminals freely available. So may be occupied by 2 terminal 25 from Group 2 as transmission channel 1 through terminal 1 of group 1 and and transmission channel. To each group to be able to reserve a minimum number of free available transmission channels, for example, 16 of the 64 transmission channels are reserved as the minimum number for Group 1 and another 16 of the 64 transmission channels reserved as minimum number of Groups 2. The remaining 32 transmission channels can then be used, depending on traffic and demand from both end points of the group 1 and from terminal stations of the group. 2 This gives freedom, and automatically adapts the allocation of transmission channels at the level of traffic. An additional advantage is that each terminal more than one transmission channel can be assigned, which widens the scope of application, for example to services with different transmission capacity, for example, different image qualities to different fees offered.

In one advantageous embodiment of the invention, the minimum number of reserved transmission channels can be dynamically varied. This gives the additional advantage of a more flexible allocation of transmission channels. Thus, the suggested minimum number can be changed without interrupting the operation and adapted to the current volume of traffic, for example by commissioning a new or extended system, whereby an optimum utilization of the available transmission capacity can be achieved.

In a further advantageous embodiment of the invention, the transmission channels can be temporarily blocked virtual memory. This has the advantage that limited the system remains operational even during a repair required in case of failure of one or more transmission channels, by merely being repaired transmission channels are virtually closed and thus are considered occupied.

Further advantageous embodiments of the invention are disclosed in the dependent claims.

An embodiment of the invention will be explained in the following with the aid of a figure. The figure shows a schematic illustration of a services-on-demand system with a device according to the invention for assigning transmission channels.

The services-on-demand system SYS, a so-called service-on-demand system includes a server SER, a management unit VER, a device according to the invention ON for assigning transmission channels and multiple terminals END1, END2.

The server SER is connected via the device A to the plurality of terminal stations END1, END2 via a point-to-multipoint connection. The server SER is designed to provide the end user END1, END2 services. As service recordable as pay per view, near video on demand, video on demand, telelearning / Teleteaching, information services, teleshopping or video games are available. The user of a terminal END1, END2 selected via a decoder, a so-called set-top box from a service which is then provided by the server SER at his disposal, for example by dubbing the retrieved video film. the server SER requires at least a free transmission channel to dub. The terminal END1; END2 needs to know which communication channel is used by the server SER to receive the dubbed Videeofilm. To assign the transmission channels, the facility EIN is used.

The facility EIN for assigning transmission channels to terminals END1, END2 includes at least two interfaces S1, S2 for connecting 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 E connected ND1 END2. The interfaces S1 and S2 are respectively the protocol conversion, as a send unit for transmitting information from the device to the terminals ON END1, END2 and as a receiving unit for receiving information from the end user END1, END2.

The facility EIN further includes a memory MEMO, where an allocation table is stored. The memory MEMO is for example a so-called RAM, EEPROM or 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 evidenced when used for an individual transfer from the server SER to a specific terminal END1, END2. Such a transmission channel with a video-on-demand connection is provided exclusively for a particular terminal END1, END2 available to allow the terminal END1, END2 operations such as fast forward, fast rewind or stop image. In a near-video-on-demand link may be a transmission channel by a plurality of terminals END1, END2 be used at the same time, as only a unidirectional flow of information from the server SER to the terminals END1, END2 takes place. The transmission channel is considered then as long as occupied as long as one of the parties to the service near video-on-demand terminal stations END1, END2 resume service with claim or the transfer is complete.

The allocation table is designed so that a variable assignment between transmission channels and terminals END1, END2 is possible, regardless of the group affiliation of the terminal stations. This will be illustrated using a numerical example: Group 1, which is connected to the interface S1, for example, includes 10 terminals END1. The group 2, which is connected to the interface S2 includes, for example, 10 terminals END2. There are 10 transmission channels provided to supply the 20 terminals END1, END2. Because an estimated traffic would have 10 transmission channels are sufficient without leading to shortages, as will simultaneously take no more than 50% of the terminals END1, END2 a group using a service normally. Thus, it would be sufficient to assign 5 selected transmission channels of group 1 at leisure and 5 more transmission channels of the group 2. Due to statistical tolerances in the estimation of the volume of traffic and, for example, an active use of services of terminals END1 the group 1 compared with a restrained use services of terminals allowed END2 group 2 aside, it might happen that 8 of the 10 terminals of the group 1 want to take a service or assistance, while only 2 of the 10 terminals END2 the group 2, this would simultaneously. With a fixed assignment of the transmission channels in Figure 5 for group 1 and 5 in Group 2, this would not be possible. For this reason, a variable allocation of transmission channels is selected, which provides only 10 freely assignable transmission channels for a total of 20 terminals END1, END2, independent of a group membership, so that 8 locations END 1 the group 1 and 2 terminals END2 group 2 simultaneously a can take repair. In addition, in this way a terminal END1, END2 also be assigned more than one transmission channel, for example, 2 or 3 simultaneously.

The device A further includes a control unit CTRL, which is connected to the interfaces S1, S2 and the memory MEMO. The control unit CTRL is for example a processor, for example a so-called DSP or a microprocessor. The control unit CTRL is adapted to receive connection requests from individual terminals END1, END2 for retrieval of services. For this purpose, in the control unit CTRL, a signaling unit is provided. The signaling unit detects a light emitted from a terminal END1, END2 connection request and then switches on a control channel between server SER and terminal END1, END2 free so that the terminal END1, END2 can access their desired services. Thereafter, the control unit CTRL of terminal END1, END2 least one transmission channel to selected from those available in memory MEMO and the number matched to the retrieved serving. The terminal END1, END2 can then the retrieved service relating to the trading or the zugwiesenen transmission channels available. In addition, the one or more assigned transmission channels in the memory MEMO is marked as occupied.

can only be assigned transmission channels, which are in the memory MEMO than currently available. Are all transmission channels in the memory MEMO as busy, so will the individual terminals END1, END2 notified by the control unit CTRL that currently, a connection is not possible. The control unit CTRL can for example be programmed such that it for after a message to a terminal END1, END2 that a connection is not possible to monitor the memory MEMO and the corresponding terminal END1, END2 informed as soon as a transmission channel is considered unassigned and again Available.

The control unit CTRL is adapted to the allocation of the transmission channels to carry out such that for each group of terminals END1, END2, a minimum value of assignable transmission channels does not fall below and a maximum value of assignable transmission channels is not exceeded, said minimum value and maximum value are unequal. A numerical example illustrates this: The Group 1, which is connected to the interface S1, for example, includes 30 terminals END1. The group 2, which is connected to the interface S2, for example, includes 30 terminals END2. There are 30 transmission channels provided to supply the 60 terminals END1, END2. 10 of the 30 transmission channels are kept free, so that they are available for the terminals END1 the group 1 at leisure. 10 more of the 30 transmission channels are kept free, so that they are available for the terminals END2 Group 2 at leisure. It does not matter which are kept free of the 30 transmission channels, important is their absolute number. The absolute number 10 represents the minimum value which can be input in the control unit CTRL in the initialization of the system SYS. The remaining 10 transmission channels can then be used by both terminals END1 the group 1 and of terminals END2 Group 2, so as to provide a maximum of 20 transmission channels for each group. The maximum value can be entered during the initialization of the system SYS in 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, as are specified by the maximum value, for example 21 instead of 20, and at the same time but only example 5 of the 10 transmission channels, which are provided for the other group are busy, the requested 21 transmission channel for the first group shall 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 communication channels at your disposal, in the example 10th

The control unit CTRL can for example be programmed such that it is suitable to change the minimum values ​​and / or the maximum values ​​dynamically; for example, can be monitored by the control unit CTRL to the initialization phase, the actual traffic and the minimum values ​​and the maximum values ​​are adapted. The dynamsiche changes the minimum values ​​and maximum values ​​is carried out without interruption of the operation by using software, the values ​​are programmed, for example by means of a keyboard or the control unit CTRL is programmed so that it automatically performs the adjustment. The latter is for example realized by the control unit, always noted the number of simultaneously occupied by a group of transmission channels for a fixed period, eg one week and then re-sets the maximum number of occurrences assignments as a minimum value for the respective group.

Furthermore, the control unit CTRL can be programmed such that it is appropriate to temporarily block individual transmission channels or groups of transmission channels in the memory MEMO virtually, so that these transmission channels are considered busy. This has the advantage that, for example in case of repair of a transmission channel is not the entire system must be shut down, but only want to repair 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 repair of a transmission channel for example, 19 of the 20 transmission channels still available. Through virtual lock and unlock of transmission channels, the capacity of the available for a specific number of terminals END1, END2 transmission channels can also be varied in a simple manner. If the system is as extended, for example by connecting additional terminals END1, END2 or by making available additional, possibly transmission capacity intensive services, so can be adapted to the then had grown traffic, the number of transmission channels by additionally provided transmission channels are activated and thus the end user END1, END2 sets on service available.

The system SYS may further comprise a management unit VER. The management unit VER includes, for example, a processor, it monitored by means of which the volume of traffic throughout the system SYS. So the system has, for example, a plurality of means ON for allocating transmission channels, each connected to the central server SER and the central management unit VER. In this way, monitoring functions in the management unit VER can centralize, which is accompanied by a reduction of technical effort. Managing the system SYS is commonly referred to as management or network management. Thus, the management unit to take for example the monitoring of the functioning of the transmission channels by, for example, test measurements on unoccupied transmission channels and the device ON then the instruction transmit individual transmission channels virtually lock, if this example are faulty and repair is necessary. The facility EIN includes for this purpose an interface S3 to management unit VER. The control unit CTRL is connected to this interface S3 and as adapted to receive via this interface S3 information about which are to lock the transmission channels virtually. The interface S3 is used for protocol conversion, as a send unit for transmitting information from the facility EIN to management unit VER and a receiving unit for receiving information from the management unit VER.

The controller CTRL may be adapted to receive via the interface S3, the information should apply which minimum values ​​and which maximum values ​​for which group of terminals END1, END2. For example, the management unit VER monitors the current traffic volume and thereby determines those minimum and maximum values ​​that exploit a given transmission capacity and optimal END1 END2 offer the end user, the maximum service.

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

When setting ON for allocating transmission channels an interface S4 to the server SER is provided. The control unit CTRL is connected to this interface S4 and suitable, the information which transmission channels to which terminal END1, END2 assigned to transmit via the interface S4 to the server SER, so that the server SER knows which communication channel he put the retrieved service available should. The interface S4 is the protocol conversion, as a transmitting unit for transmitting information from the facility EIN to the server SER and a receiving unit for receiving information from the server SER. The device can contact well before the assignment of the transmission channels to the server SER, for example, querying the server SER, much transmission channels for a retrieved from a terminal END1, END2 service are required.

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