PDCCH Scrambling for Multicast Broadcast Services
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Solution Overview
Problem
Current wireless communication systems face challenges in efficiently transmitting physical downlink control channels for multicast/broadcast services due to limitations in payload scrambling sequences and hash functions, which inhibit multicast and broadcast communications, affecting network performance.
Innovation Solution
The method involves configuring a plurality of group-RNTIs for a cell and using specific payload scrambling sequences and hash functions based on a value of zero or group-RNTI for physical downlink control channels, enabling efficient scheduling of multicast/broadcast services by allowing multiple UEs to receive shared transmissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional payload scrambling sequences and hash functions are used for PDCCH transmissions, then single-user communications are supported, but multicast and broadcast communications are inhibited
Solution Approach 1:
The patent modifies the RNTI parameter from conventional single-user values to group-RNTI values (where the most significant bit is set to 1) for multicast/broadcast services. This parameter change enables the PDCCH payload scrambling sequence and hash function to generate different scrambling behaviors, thereby supporting group communications while maintaining single-user communication reliability through separate RNTI configurations.
2Adaptability or versatility
If group-RNTI with most significant bit set to 1 is used for scrambling, then multicast/broadcast services are enabled, but conventional single-user scheduling may be affected
Solution Approach 1:
The patent segments the RNTI space into two distinct segments: conventional RNTIs (most significant bit = 0) for single-user communications and group-RNTIs (most significant bit = 1) for multicast/broadcast services. This segmentation allows the system to independently configure and operate single-user and group communications without interference, as each segment uses its own scrambling sequence and hash function calculations.
3Adaptability or versatility
If multiple G-RNTIs are configured for a cell, then multiple multicast services are supported, but UE complexity in monitoring search spaces increases
Solution Approach 1:
The network performs preliminary configuration of multiple G-RNTIs and their associated search spaces before multicast service operation. The network node provides RRC configuration information that pre-defines the mapping between G-RNTIs and search space sets, allowing UEs to efficiently monitor multiple multicast services without dynamically calculating search space positions during operation, thereby reducing real-time processing complexity.
Data Source
AI summary
Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a user equipment (UE) may monitor a search space associated with a physical downlink control channel (PDCCH) corresponding to a multicast/broadcast (MBS) physical downlink shared channel (PDSCH) for at least one MBS PDCCH communication having a payload that is scrambled according to a PDCCH payload scrambling sequence based on a value of a radio network temporary identifier (RNTI), wherein the value of the RNTI is equal to a group-RNTI (G-RNTI) or zero. The UE may receive the at least one MBS PDCCH communication. Numerous other aspects are described.