LTE Network-Wide Broadcasting via SFN Clustering
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Solution Overview
Problem
Current LTE deployments face challenges in efficiently delivering high-bandwidth broadcast content to a large audience due to limitations in resource utilization and inter-cell interference, particularly in Evolved-Multimedia Broadcast Multicast Services (eMBMS) systems, where base stations are constrained by a common modulation scheme, leading to reduced data rates and increased interference.
Innovation Solution
A method and system for network-wide broadcasting that identifies interference dependencies between base stations to generate single frequency network (SFN) clusters, progressively creating smaller clusters until a target modulation and coding scheme threshold is met, and selects an SFN cluster with a maximum common modulation and coding scheme for all clusters, integrating resource block allocation to maximize system utility by considering the sum of broadcast and unicast flows.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If base stations use a common modulation scheme for broadcast content in SFN, then transmit diversity gain is improved, but resource utilization deteriorates
Solution Approach 1:
The patent segments the network into multiple SFN clusters, where each cluster uses a common modulation scheme internally (maintaining transmit diversity gain), while different clusters can use different modulation schemes (improving resource utilization). This segmentation allows base stations to operate in coordinated groups rather than forcing a single common scheme across the entire network.
Solution Approach 2:
The patent applies local quality by allowing different modulation and coding schemes (MCS) to be used in different SFN clusters based on local channel conditions and user requirements. Each cluster can optimize its transmission parameters independently, so that clusters with good channel conditions can use higher-order modulations while clusters with poor conditions use more robust schemes.
2Productivity
If base stations are excluded from SFN to utilize resources better, then resource utilization is improved, but inter-cell interference increases
Solution Approach 1:
By segmenting the network into SFN clusters, the patent creates localized coordination zones where base stations transmit with common MCS. This segmentation reduces inter-cell interference compared to a fully independent operation, while still allowing resource utilization improvement compared to a single large SFN covering the entire network.
Solution Approach 2:
The patent dynamically adjusts the SFN cluster configuration and MCS selection based on channel conditions and traffic demands. Base stations can transition between being part of an SFN cluster and operating independently, allowing the system to adaptively balance resource utilization and interference management.
3Productivity
If smaller SFN clusters are created to improve resource utilization, then resource multiplexing gain is improved, but transmit diversity gain decreases
Solution Approach 1:
The patent creates multiple SFN clusters of appropriate sizes segmented from the overall network. This segmentation allows the system to achieve resource multiplexing gain by having multiple clusters operate with different MCS, while maintaining sufficient transmit diversity gain within each cluster through coordinated transmission among its member base stations.
Solution Approach 2:
The patent changes the parameter of cluster size to optimize the trade-off between resource multiplexing gain and transmit diversity gain. By adjusting the number of base stations in each SFN cluster, the system can find the optimal balance where clusters are small enough to allow different MCS usage but large enough to provide adequate diversity gain.
Data Source
AI summary
A system and method for network-wide broadcasting, including identifying interference dependencies between base stations (eNBs) to generate one or more single frequency network (SFN) clusters for one or more broadcast sessions. The generating of SFN clusters includes performing a controlled decrease in transmit diversity gain for each of the sessions by progressively creating smaller SFN clusters, iteratively creating the smaller SFN clusters until a target modulation and coding scheme (MCS) threshold is met to generate a plurality of SFN clusters, and selecting an SFN cluster with a maximum common MCS for all SFN clusters in a set. Resource block (RB) allocation is integrated with the generating of the SFN clusters to determine maximum system utility, and the system utility considers the sum of the utilities of broadcast and unicast flows. Network-wide broadcasting is controlled based on the determined maximum system utility.