Method and apparatus for scheduling packets

• Main Authors: JURCA, DAN, MUNARETTO, DANIELE, WIDMER, JOERG
• Format: Patent
• Language: English; French; German
• Published: 23.11.2011
• Subjects: ELECTRIC COMMUNICATION TECHNIQUE; ELECTRICITY; TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHICCOMMUNICATION

A scheduling method for scheduling packets of a plurality of n video streams which are multicast or broadcast at a base station, said scheduling method selecting from the available queues at each scheduling round the queue from which the next packet is to be scheduled for transmission, said scheduling method performing said selection based the following: a set of initial parameters which are provided to said scheduler in advance of said selection and which are based on average channel conditions averaged over more than one scheduling round, said parameters comprising: i) the number n of queues qi, where each queue qi contains packets from a specific video stream of said n video streams; ii) for each queue qi, the intended modulation and coding scheme MCi for the broadcast transmissions of said queue qi; iii) for each queue qi, the intended number of users NUAVGi for the reception of packets from said queue qi; and said selection further being based on instantaneous channel conditions of the individual users receiving said video streams, wherein said scheduling method further comprising: for each queue qi, determining whether based on the instantaneous channel conditions of the users a variation of said set of initial parameters is possible by determining one of the following: a) for each queue qi, determining the difference between the intended number of users NUAVGi and the instantaneous number of users which are able to receive packets from that queue qi based on the modulation and coding scheme qi to thereby obtain a differential number of users DUi for said queue qi as a possible variation of said parameters; or b) for each queue qi, determining a higher modulation and coding scheme HMCi different from the one assigned to this queue qi by said initial set of parameters as a possible variation of said initial parameters, said higher modulation and coding scheme HMCi being determined such that it achieves a higher possible rate, and further being determined under the condition that the expected instantaneous number of users which based on their instantaneous channel condition are able to decode said higher modulation and coding scheme HMCi is at least as large as the intended number of users NUAVGi for said queue qi as given by said initial set of parameters; and said method further comprising: based on said possible variation of parameters (DUi or HMCi), determining for each queue qi a profit indicator indicating the overall profit for the network or the users if said variation of initial parameters is used for transmitting the next packet; selecting the queue qi for which said profit indicator is maximum as the queue from which the next packet is selected.