OFDM Broadcast Packet Multiplexing for Resource Efficiency
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Solution Overview
Problem
Conventional mobile communication systems, such as CDMA2000 HRPD, face inefficiencies in resource utilization and increased system load when providing broadcast services to multiple users, as they either waste resources or compromise transmission rate to achieve diversity gain.
Innovation Solution
A multiplexing method and apparatus for the OFDM system that multiplexes multiple logical channels into one time slot by assigning packets to OFDM symbols or subcarriers, allowing for increased transmission efficiency and diversity gain by optimizing the transmission structure to include multiple symbols and subcarriers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If unicast scheme is used to provide broadcast service data to multiple users, then transmission rate can be maintained, but network resources are wasted and system load increases
Solution Approach 1:
The patent combines multiple logical channels carrying the same broadcast service data into a single physical transmission stream. By merging redundant unicast transmissions into one shared broadcast channel, the system maintains full transmission rate while eliminating network resource waste and reducing system load.
Solution Approach 2:
The patent creates a universal broadcast channel that can serve multiple users simultaneously with the same data stream. This multi-functional channel structure allows any number of users to receive identical broadcast content without requiring separate dedicated resources for each user.
2Reliability
If conventional ECB structure is used for broadcast services, then transmission structure can be established, but frequency efficiency is reduced and diversity gain is compromised
Solution Approach 1:
The patent transitions from conventional time-slot-based transmission to a two-dimensional OFDM structure using subcarriers and symbols. This dimensional change enables simultaneous transmission of multiple packets across different subcarrier groups within the same time frequency resource, achieving both frequency efficiency and diversity gain through spatial-frequency diversity.
Solution Approach 2:
The patent segments the broadcast data into multiple packets that are distributed across different subcarrier groups and OFDM symbols. This segmentation creates multiple transmission paths through the channel, providing diversity gain while efficiently utilizing available frequency resources through parallel transmission.
3Productivity
If multiple logical channels are multiplexed into one time slot, then frequency efficiency is enhanced, but transmission structure complexity increases
Solution Approach 1:
The patent resolves structural complexity by organizing multiplexed logical channels along OFDM dimensions (subcarriers and symbols) rather than traditional time slots. This dimensional reorganization provides a systematic framework for managing multiple channels, where complex multiplexing patterns become manageable through standardized OFDM processing and resource element mapping.
Data Source
AI summary
An apparatus and method for multiplexing packets for broadcast services in a mobile communication system based on orthogonal frequency division multiplexing (OFDM). The OFDM system has a transmission structure in which one slot includes at least two symbols, and each symbol includes a plurality of subcarriers. Different broadcast service packets received from at least two channels are multiplexed into one slot and a result of the multiplexing is transmitted. Overhead information of the channel packets multiplexed into the one slot is generated and transmitted.