Unified Mobile TDM-PON Uplink MAC Scheduling
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Solution Overview
Problem
Current mobile DBA uplink schemes for TDM-PON based mobile fronthaul face issues such as noise transmission when no data is sent and inability to respond to fast changes in mobile traffic, due to fixed transmission rates and reliance on averaged statistical traffic analysis, which does not account for delay in Ethernet passive optical networks.
Innovation Solution
A unified mobile and TDM-PON uplink MAC scheduling method that maps LTE wireless MAC scheduling to TDM-PON MAC scheduling, synchronizes RRUs to account for varying optical path delays, and performs FFT and cyclic prefix removal at the RRU, reducing bandwidth requirements and eliminating unnecessary data transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If fixed transmission rates are used in mobile DBA uplink schemes, then device complexity is reduced, but the system cannot respond to fast changes in mobile traffic
Solution Approach 1:
The patent implements dynamic bandwidth allocation where the BBU adjusts uplink bandwidth grants in real-time based on actual traffic conditions. The scheduling is dynamically adapted each frame based on buffer status reports from RRUs and current traffic load, allowing the system to respond to fast traffic changes while maintaining manageable complexity through structured algorithms.
Solution Approach 2:
The system employs feedback mechanisms where RRUs send buffer status reports to the BBU, which then adjusts bandwidth allocation in subsequent frames. This closed-loop feedback enables the system to adapt to traffic variations without requiring overly complex predictive models, balancing adaptability with computational feasibility.
2Loss of time
If averaged statistical traffic analysis is used, then device complexity is reduced, but delay in Ethernet passive optical networks is not accounted for
Solution Approach 1:
The patent incorporates preliminary delay compensation by calculating and accounting for optical network delays in advance when determining bandwidth allocation. The BBU compensates for propagation delays by adjusting timing and scheduling decisions proactively, ensuring that delay-sensitive traffic is handled appropriately without requiring complex real-time delay measurement and adjustment mechanisms.
Solution Approach 2:
The system dynamically adjusts scheduling parameters such as timing offsets and bandwidth allocation based on measured or estimated delay characteristics of the optical network. By changing these parameters adaptively, the system accounts for network delay without implementing overly complex scheduling algorithms.
3Reliability
If continuous transmission is used to maintain connection, then reliability is improved, but noise transmission occurs when no data is sent
Solution Approach 1:
The patent implements periodic bandwidth allocation where the BBU grants uplink bandwidth in discrete time slots rather than continuous transmission. RRUs transmit data only when granted bandwidth is available, and remain silent otherwise. This periodic scheduling maintains connection reliability through regular scheduling opportunities while eliminating continuous noise transmission during idle periods.
Solution Approach 2:
The system allows RRUs to self-manage their transmission by monitoring their own buffer status and requesting bandwidth only when data is available for transmission. This self-service approach ensures that noise is not transmitted during idle periods while maintaining reliable connectivity through on-demand bandwidth requests and grants.
4Productivity
If full bandwidth is allocated to each RRU, then adaptability is improved, but bandwidth efficiency decreases due to inability to share bandwidth dynamically
Solution Approach 1:
The patent merges the bandwidth allocation control at the BBU level, allowing multiple RRUs to share the uplink bandwidth pool dynamically. The BBU consolidates bandwidth requests from multiple RRUs and allocates grants optimally, enabling bandwidth sharing and improving overall efficiency while maintaining flexibility through centralized control and adaptive grant allocation.
Solution Approach 2:
The BBU serves multiple RRUs with a single unified bandwidth allocation mechanism, making the bandwidth pool universally available to any RRU that needs it. This multi-functional approach allows the same bandwidth resources to serve different RRUs at different times based on actual traffic needs, improving efficiency while maintaining adaptability through the universal scheduling framework.
Data Source
Figure 1
Figure 2A
Figure 2B~2C
AI summary
Disclosed herein are various embodiments that include a method and a passive optical network (PON) for supporting a mobile network. In various embodiments, a baseband unit (BBU) is configured to measure an optical path delay from each remote radio unit (RRU) of a plurality of RRUs to the BBU during an initialization phase. The BBU synchronizes all the RRUs in the mobile system by adjusting the timing of each path based on the optical path delay between each RRU and the BBU. The BBU determines a mapping rule that maps each resource block assigned to each RRU of the plurality of RRUs to a different PON transport block. The BBU transmits the mapping rule to each RRU of the plurality of RRUs. In certain embodiments, the mapping rule may be recalculated dynamically after the initialization phase.