Information change transmission method and device for single-cell multicast service
Patent No. US10785764 (titled "Information change transmission method and device for single-cell multicast service") on Aug 10, 2017. The application was issued on Sep 22, 2020.
What is this patent about?
'764 is related to the field of wireless communication, specifically addressing the challenge of efficiently notifying narrowband Internet of Things (NB-IoT) devices about changes in single-cell multicast control channel (SC-MCCH) information. Existing LTE systems use a single subframe for change indication and scheduling, which is not feasible in the cost-sensitive and bandwidth-constrained NB-IoT environment. The patent aims to reduce power consumption and improve efficiency in multicast service delivery for NB-IoT.
The underlying idea behind '764 is to use two separate narrowband physical downlink control channels (NPDCCHs) with different transmission periods to signal changes in the SC-MCCH information. One NPDCCH alerts the device to a potential change, while the other NPDCCH, transmitted at a different periodicity, provides the actual scheduling information for receiving the updated SC-MCCH data. This separation allows the device to avoid unnecessary SC-MCCH reception when no changes have occurred, conserving power.
The claims of '764 focus on a user equipment (UE) and a base station configured to transmit and receive SC-MCCH information. The UE receives a second downlink control information (DCI) format on a second NPDCCH to detect SC-MCCH information change notifications. If a change is indicated, the UE then uses a first DCI format on a first NPDCCH to acquire the updated SC-MCCH information. Crucially, the transmission periods of the first and second NPDCCHs are different, and the first DCI format indicates the resource for transmitting the updated SC-MCCH information.
In practice, the base station transmits the initial SC-MCCH information and then uses the second NPDCCH, transmitted less frequently, to signal any changes. This change notification can be embedded directly in the DCI of the second NPDCCH or within a message indicated by that DCI. Upon receiving the change notification, the UE then monitors the first NPDCCH, transmitted more frequently, to obtain the scheduling information needed to receive the updated SC-MCCH. This decoupling of change notification and scheduling is key to the invention.
This approach differentiates from prior solutions by avoiding the simultaneous transmission of change indications and scheduling information within a single subframe, which is not supported in NB-IoT due to its narrowband design. By using separate NPDCCHs with different transmission periods, the invention reduces the UE's power consumption by minimizing unnecessary SC-MCCH receptions. Furthermore, the use of multiple bits in the change notification can allow for indicating changes to specific services, further refining the process and reducing unnecessary power consumption.
How does this patent fit in bigger picture?
Technical Landscape
In the mid-2010s when ’764 was filed, wireless communication systems were increasingly optimized for low-power, wide-area connectivity at a time when multicast services were typically implemented using wideband architectures that assumed simultaneous processing of control and data signals. When systems commonly relied on high-bandwidth physical channels to deliver change notifications and scheduling information within the same subframe, hardware and software constraints in narrowband environments made such concurrent processing non-trivial. Engineering practices for these constrained devices required managing control channel updates across limited frequency resources, where the overhead of monitoring for service changes could significantly impact the battery life of devices designed for long-term autonomous operation.
Prosecution Position
The examiner allowed the application because the claims specify a unique two-step process for handling multicast control information in a narrowband system. Specifically, the device uses a second control format received over multiple subframes to detect a change notification for the multicast control channel, and then uses a first control format—also received over multiple subframes—to acquire the actual updated multicast information. The examiner noted that the prior art did not teach this specific sequence where the time periods for receiving the first and second control formats are different, nor did it teach using the first control format to indicate the specific resources for the updated multicast transmission following a change notification.
Claims
This patent contains 6 claims, with independent claims numbered 1, 3, 5, and 6. Independent claims 1 and 5 are directed to a User Equipment (UE), while independent claims 3 and 6 are directed to a base station; all independent claims relate to Single-Cell Multicast Control Channel (SC-MCCH) information transmission and change notifications. The dependent claims elaborate on the structure of the second downlink control information (DCI) format.
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US10785764
- Application Number
- US16324359A
- Filing Date
- Aug 10, 2017
- Status
- Granted
- Publication Date
- Sep 22, 2020
- External Links
- Slate, USPTO, Google Patents