Broadcast Scheduling for Asymmetric Communication Environment

In a Client-Server system, data transmission from server to client can be performed in two ways: Pull-Based and Push-Based. In Pull-Based transmission, client sends requests to server to ask for data. In Push-Based transmission, server pushes data to client.

One kind of Client-Server systems is called Asymmetric Communication System, where the downstream (server to client) communication capacity is much greater than the upstream (client to server) capacity. In such system, it is believe that the broadcast is an efficient way to transmit data from server to client. Wireless network is such a system.

How to schedule data to broadcast is of importance in the overall system performance. Right now, most researches are focusing on either Pull-Based system or Push-Based system. However, fully pushed-based broadcast may not be useful for some clients, and fully pull-based broadcast may not be efficient. We are considering to combine scheduling for these two systems to make it to be of practicability.

There are some ideas for consideration:

1. Combining Pull-Based scheduling with Push-Based scheduling. In purely Push-Based system, the data items to be transmitted are fixed. We just need to set the order to broadcast. If the amount of data items is huge, it may not be good to transmit each of them. In such condition, Pull-Based model is appreciated to set which item need to be transmitted.
2. Arranging channels for Pull-Based broadcast and Push-Based broadcast separately. The Pull-Based broadcast is for most popular and regular data items. The Push-Based broadcast is for less popular and irregular items.
3. Need Long-term scheduling for Push-Based broadcast channel and Short-term scheduling for Pull-Based broadcast channel.
4. Combining several scheduling criteria, such as popularity, priority, waiting time, stretch, service time. Scheduling based on just one criteria, which is the way most proposals do right now, may not be good enough.

People

• Sourav Pal