Multiplexing scheme for unicast and broadcast/multicast traffic

Abstract

A method is provided for efficiently multiplexing interlaced broadcast traffic over a wireless network. The multiplexing scheme organizes unused slots in at least some base stations so that unicast traffic employing hybrid ARQ may be delivered therein.

Description

BACKGROUND OF THE INVENTION [0001] 1. Field of the Invention [0002] This invention relates generally to telecommunications, and more particularly, to wireless communications. [0003] 2. Description of the Related Art [0004] In the field of wireless data systems, a number of well-known standards, such as 1x-EV-DO, 1xEV-DV as well as the High Speed Downlink Packet Access (HSDPA) specification in the Universal Mobile Telecommunication System (UMTS) standard, have been employed. Newer technologies such as fast scheduling, adaptive modulation and coding (AMC) and hybrid ARQ (HARQ) have also been introduced to improve overall system capacity. However, application of the above-mentioned techniques has been limited to transmitting data blocks for unicast traffic, i.e. a data block addressed to a single mobile station. In general, a scheduler selects a user for transmission at a given time and adaptive modulation and coding is used to select an appropriate transport format (modulation and cod...

AI Technical Summary

Problems solved by technology

However, application of the above-mentioned techniques has been limited to transmitting data blocks for unicast traffic, i.e. a data block addressed to a single mobile station.

Due to errors in channel quality estimates, a relatively high level of frame errors may occur in the transmissions performed at a given rate (transport format).

The interlace-based multiplexing approach used in the prior art poses problems when different broadcast data rates are used by different base stations in different cells in the system.

The larger cells have, in general, larger path loss and therefore cannot support very high data rates.

Therefore, these subpackets potentially get interference from both cell set A and cell set B.

However, the unicast traffic uses hybrid ARQ and potentially requires multiple retransmission attempts.

Therefore, a retransmission cannot be performed for unicast traffic.

Thus, these unused slots remain unavailable, and, therefore, the multiplexing approach used in the prior art poses serious restrictions on scheduling and results in system inefficiency.

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