TTI Bundling for MTC Downlink Control Channels

The patent segments control channel candidates into different types (common search space candidates and UE-specific search space candidates) and applies different processing rules to each type. This segmentation allows the system to reduce overhead for certain candidates while maintaining coverage improvement through TTI bundling for others, thus resolving the contradiction between coverage enhancement and overhead reduction.

The patent implements partial action by selectively monitoring decoding candidates based on their type and aggregation level. Instead of monitoring all possible candidates in bundled subframes, the system applies different monitoring strategies: common search space candidates are monitored with specific aggregation levels while UE-specific candidates are handled differently. This partial monitoring approach reduces decoding complexity while maintaining sufficient reliability for MTC devices.

The patent achieves universality by designing a TTI bundling mechanism for control channels that is compatible with existing LTE standards while serving MTC devices. The solution uses standard PDCCH and EPDCCH structures with modified monitoring behavior rather than requiring new physical channels or fundamental standard changes. This allows the same mechanism to serve both legacy devices and MTC devices, enhancing coverage for low-cost devices without creating incompatibility issues.