Semi-Persistent Scheduling for CIoT Uplink Overhead Reduction
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Solution Overview
Problem
In cellular Internet of Things (CIoT) systems, machine-type communication devices perform periodic uplink transmissions, leading to redundant random access and resource allocation, which increases overhead and collision on the random access channel, wasting power in low-power devices.
Innovation Solution
Implementing semi-permanent scheduling (SPS) in base station-UE communication, where user equipment (UE) transmits a random access request with identification information to receive a semi-permanent scheduling UE ID and uplink resource allocation, allowing periodic data transmission without repeated random access requests.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If periodic uplink transmissions are performed using conventional random access procedures, then data can be transmitted periodically, but random access overhead increases and collisions occur more frequently
Solution Approach 1:
The base station performs preliminary scheduling of uplink resources for periodic transmissions before the actual data transmission occurs. The SPS configuration message pre-allocates time-frequency resources and transmission parameters, so that periodic uplink transmissions can occur without repeated random access procedures, thereby reducing overhead and avoiding collisions.
Solution Approach 2:
A semi-persistent scheduling configuration message acts as an intermediary between the base station and UE for periodic uplink transmissions. This configuration message establishes a dedicated scheduling pattern that mediates the resource allocation, allowing periodic transmissions to occur without direct random access requests for each transmission instance.
2Productivity
If random access requests are sent for each periodic transmission, then uplink data can be transmitted, but power is wasted in low-power devices
Solution Approach 1:
The base station provides preliminary scheduling information through SPS configuration messages that include transmission parameters and resource allocations for periodic uplink transmissions. This allows low-power devices to transmit periodically without waking up to perform random access procedures for each transmission, thereby conserving battery power while maintaining transmission reliability.
3Quantity of substance
If semi-persistent scheduling is implemented, then random access overhead is reduced, but additional scheduling configuration is required
Solution Approach 1:
The SPS configuration message serves multiple functions simultaneously: it allocates uplink resources, defines transmission periodicity, sets power control parameters, and establishes resource patterns. This multi-functionality reduces the need for separate signaling messages and simplifies the overall scheduling configuration process despite the added capability.
Data Source
AI summary
The present invention relates to a 5G or pre-5G communication system for supporting higher data transmission rates than 4G communication systems such as LTE. The present invention provides a communication method of a terminal which communicates with a base station in a wireless communication system, the communication method comprising the motions of: transmitting, to the base station, a first random access request message comprising identification information of the terminal; receiving, as a response to the first random access request message, a response message comprising semi-persistent scheduling (SPS) terminal identity (ID) and uplink (UL) resource allocation information; and periodically transmitting, using the SPS terminal ID, UL data from a resource that is indicated by the UL resource allocation information, wherein the identification information of the terminal is information that indicates that the terminal will be appointed as an SPS terminal.