Two-Dimensional Sequence Modulation for Uplink Control Signals
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Solution Overview
Problem
The existing communication systems, particularly in the 3GPP LTE scheme, face challenges in efficiently transmitting control signals with variable amounts of information and supporting multiple user equipment (UEs) without causing interference and requiring complex cell planning, especially in multi-cell environments.
Innovation Solution
A method for generating and transmitting signals based on time/frequency domain transmission units, where the transmission sequence is modulated in both time and frequency directions within transmission units, allowing for the creation of a transmission-unit-based symbol that can be used to transmit control signals efficiently, reducing interference, and supporting multiple UEs with varying information amounts without the need for extensive cell planning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If control signals are transmitted using conventional methods in multi-cell environments, then coverage and power concentration are achieved, but interference between UEs and cell planning complexity increase
Solution Approach 1:
The patent applies two-dimensional modulation by modulating the transmission sequence in both time direction and frequency direction within transmission units. This dimensional expansion allows multiple UEs to be multiplexed in both time and frequency domains simultaneously, improving coverage and power concentration while reducing interference and eliminating the need for complex cell planning in multi-cell environments.
2Productivity
If transmission sequences are modulated only in single direction (time or frequency), then implementation is simple, but information transmission efficiency and multi-UE support are limited
Solution Approach 1:
The patent transitions from single-direction modulation to two-dimensional modulation by modulating transmission sequences in both time and frequency directions. This allows the system to transmit more information efficiently and support multiple UEs simultaneously, with the added complexity being manageable through structured modulation procedures defined in the transmission unit framework.
Solution Approach 2:
The two-dimensional modulation scheme within transmission units provides multi-functionality by simultaneously achieving efficient information transmission, supporting multiple UEs, enabling flexible resource allocation, and maintaining compatibility with existing SC-FDM frameworks, making the increased complexity worthwhile through multiple benefits.
3Reliability
If SC-FDM scheme is used for uplink transmission, then PAPR characteristics are improved and coverage is enhanced, but the ability to transmit variable amount of control information and support multiple UEs without interference is limited
Solution Approach 1:
The patent segments the transmission resource into transmission units that contain multiple OFDM symbols in the time direction. By modulating the transmission sequence in both time and frequency directions within these segmented units, the system maintains the PAPR advantages of SC-FDM while gaining the flexibility to transmit variable amounts of control information and support multiple UEs through two-dimensional modulation and resource allocation.
Data Source
AI summary
A method and a user equipment for transmitting control information in a communication system are discussed. The method according to an embodiment includes multiplying a transmission information symbol s for the control information by a frequency direction sequence c(k) to generate a first output sequence s(k), where s(k)=s*c(k), k=0, . . . , Nk−1, and Nk corresponds to a number of subcarriers included in a resource block allocated for an uplink control channel; multiplying the first output sequence s(k) by a time direction sequence x(n) to generate a second output sequence s(k, n), where s(k, n)=s(k)*x(n), n=0, . . . , Nn−1, and Nn corresponds to a number of symbols used for transmission of the control information in a transmission time interval; and transmitting the second output sequence s(k, n) through the uplink control channel in the transmission time interval.