Control Channel Allocation in Synchronous HRPD and OFDM Systems
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Solution Overview
Problem
Current mobile communication systems, such as HRPD Rev. A and B systems, face inefficiencies in using frequency resources and supporting broadband data transmission, particularly in transmitting control information effectively.
Innovation Solution
The apparatus and method involve a transmitter that modulates packet data, measures power for the control channel, and selects between a MAC channel and an OFDM symbol to allocate control information based on power comparisons, allowing efficient transmission and reception of ACK/NACK and PCB information in a single slot, thereby optimizing power usage and supporting high-speed packet communication.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If control information is transmitted using traditional HRPD MAC channels, then compatibility with legacy systems is maintained, but transmission efficiency and broadband support are insufficient
Solution Approach 1:
The patent combines the MAC channel and OFDM symbol into a unified control information transmission mechanism. The transmitter can selectively allocate control information to either the MAC channel or OFDM symbol based on power conditions, merging the advantages of both traditional HRPD compatibility and modern OFDM efficiency to resolve the contradiction between legacy compatibility and broadband transmission efficiency.
Solution Approach 2:
The patent introduces dynamic selection between MAC channel and OFDM symbol for control information transmission. The system adapts its transmission mode based on real-time power measurements and buffer status, dynamically switching between traditional MAC channel transmission and OFDM-based transmission to optimize performance under different conditions.
2Reliability
If multiple slots are used for data transmission, then reliability is improved, but transmission capacity and speed are reduced
Solution Approach 1:
The patent extracts control information transmission from the traditional multi-slot MAC channel framework and relocates it to OFDM symbols where it can be transmitted more efficiently. By separating control information from data transmission and using dedicated OFDM symbols for control, the system achieves both reliable control delivery and high-speed data transmission within the same slot.
3Reliability
If power is allocated to control channels, then control information reliability is improved, but available power for data transmission is reduced
Solution Approach 1:
The patent implements partial power allocation to control channels by measuring available power and selectively transmitting control information only when sufficient power is available. When power conditions are favorable, control information is transmitted with adequate power for reliability; when power is limited, the system prioritizes data transmission, achieving a balanced approach that optimizes overall power utilization.
Data Source
AI summary
An apparatus and method for efficiently transmitting/receiving a control channel in a mobile communication system simultaneously supporting a synchronous High-Rate Packet Data (HRPD) system and an Orthogonal Frequency Division Multiplexing (OFDM) system. Power of a control channel to be transmitted is measured. The measured power is compared with marginal maximum power set by a higher layer. According to the comparison result, information indicating whether a previous reverse packet has been successfully received and power control information for controlling power of a reverse link is inserted and transmitted in at least one of a Medium Access Control (MAC) channel and an OFDM symbol.