Radio Link Protocols for Multi-Link Sequence Number Management
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Solution Overview
Problem
Multi-link communication systems face inefficiencies in data transmission due to non-contiguous sequence numbers of packets received through different communication links, leading to excessive negative acknowledgment messages and spurious re-transmissions.
Innovation Solution
A new set of radio link protocols (RLPs) is introduced, which segment upper-layer packets into link-layer packets with a first sequence number (SAR_seq) and a second sequence number (ARQ_seq) associated with a particular communication link, allowing receivers to detect missing packets and request re-transmissions efficiently.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If packets are transmitted over multiple communication links without link-specific sequence numbers, then data transmission can proceed simultaneously across links, but receivers cannot accurately detect missing packets leading to excessive negative acknowledgment messages and spurious re-transmissions
Solution Approach 1:
The patent segments the sequence number into two independent parts: a common sequence number (CSN) that increments across all links and a link-specific sequence number (LSN) that increments per link. This segmentation allows the receiver to accurately track packet reception per link using LSN, while maintaining overall transmission efficiency through CSN synchronization across multiple links.
Solution Approach 2:
The patent introduces sequence number fields (CSN and LSN) as intermediary structures within the packet header. These sequence number fields act as mediators between the transmission layer and reception layer, enabling accurate missing packet detection without requiring complex per-link state tracking or sacrificing multi-link transmission efficiency.
2Device complexity
If a single sequence number space is used across all communication links, then packet headers remain simple, but gaps in sequence numbers cannot be reliably detected across different links
Solution Approach 1:
The sequence number is segmented into two independent components: CSN (common sequence number) and LSN (link-specific sequence number). The LSN provides link-specific tracking precision for detecting missing packets on each communication link, while the CSN maintains overall synchronization. This segmentation increases detection precision without proportionally increasing complexity, as the additional LSN field is only present when needed for multi-link operation.
Solution Approach 2:
The patent transitions from a single-dimensional sequence number to a two-dimensional sequence number structure (CSN, LSN). This dimensional expansion allows independent tracking across multiple links without creating a single monolithic sequence number space, thereby improving missing packet detection precision while managing complexity through structured organization of sequence number fields.
3Adaptability or versatility
If sequence numbers are reset for each communication link, then packet retransmission can be managed independently per link, but the receiver cannot efficiently identify which packets are missing across multiple links
Solution Approach 1:
The sequence number is divided into CSN (common across all links) and LSN (specific to each link). The LSN enables independent per-link retransmission management by tracking packets individually on each link, while the CSN provides a global reference that allows the receiver to efficiently identify missing packets across multiple links by comparing received LSN values against expected sequences.
Solution Approach 2:
The patent implements feedback mechanisms where receivers send negative acknowledgments (NAKs) containing LSN information to indicate missing packets. This feedback loop allows senders to accurately identify which specific packets are missing on which links, enabling targeted retransmissions. The LSN field in the feedback message provides precise information about missing packets, improving identification accuracy while maintaining per-link retransmission adaptability.
Data Source
AI summary
Embodiments disclosed herein relate to a new set of radio link protocols (RLPs) configured to provide for efficient data transmission in a multi-link communication system. In an embodiment, an upper-layer packet is segmented into link-layer packets to be transmitted over a plurality of communication links, each including a first sequence number in accordance with a predetermined order. A second sequence number is further added to each link-layer packet to be transmitted for the first time. The second sequence number is configured to be in a sequence space associated with a particular communication link, and may be used for detection of missing packets.