| 摘要 |
The aim of the present invention is to propose a method to reduce the bandwidth necessary for the renewal of subscriptions to the reception of broadcast services. This aim is achieved by a method for the managing group messages for at least one receiver comprising a security module, this module comprising an identification address UA, this method being carried out by a management centre and comprising the following steps:
A. defining a maximum length for a group message,
B. defining a group command for a plurality of security modules,
C. forming a group message comprising at least the group command,
D. filling the group message with a starting address UA1 and a range LG,
E. determining a remaining length in the group message following the steps C and D,
F. defining a bitmap of variable length,
G. starting at identification address equal to the starting address UA1 and initializing an index value and the bitmap length,
H. updating the bit of the bitmap for the security module pertaining to the identification address to activate/deactivate the command for said security module,
I. compressing the bitmap,
J. checking if the compressed bitmap length is smaller than the remaining size in the group message, in the positive event, updating the index value, the bitmap length and the identification address, re-executing the steps H to J
K. updating the range in the group message with the index value and filling the group message with the bitmap. |
