Heterogeneous Pilots for LTE Resource Penalty
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Solution Overview
Problem
In LTE wireless cellular networks, the increasing demand for reference signals for advanced features like MIMO and CoMP leads to a resource penalty, where the allocation of more pilots reduces the capacity for useful data, limiting the benefits of these features.
Innovation Solution
The implementation of heterogeneous pilots, which have different signal structures and characteristics from the primary information-bearing signal, using spread-spectrum signals and orthogonal families, allowing for multiple pilots to be transmitted without using resources allocated to the primary signal, and enabling cancellation at the receive-device to minimize interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If more reference signals are allocated for advanced features like MIMO and CoMP, then the capability to support advanced features is improved, but the resource elements available for useful data decrease
Solution Approach 1:
The patent extracts the reference signal transmission from the conventional resource element allocation framework by introducing heterogeneous pilots with different signal structures and characteristics from the primary information-bearing signal. This allows reference signals to be transmitted without occupying resource elements allocated for useful data, effectively separating the two functions that were previously competing for the same resources.
Solution Approach 2:
The patent changes the signal structure parameters of pilots by introducing heterogeneous pilots with different characteristics (e.g., different waveforms, different resource allocations) compared to conventional reference signals. This parameter differentiation enables the system to support multiple advanced features simultaneously without the resource penalty that would normally accompany increased reference signal allocation.
2Quantity of substance
If heterogeneous pilots with different signal structures are used, then the number of pilots that can be transmitted is increased, but the complexity of signal processing at the receive-device increases
Solution Approach 1:
The patent segments the pilot signals into heterogeneous types with distinct signal structures and characteristics. Each heterogeneous pilot type is designed with specific properties that make it distinguishable from others and from the primary information-bearing signal. This segmentation allows the receive-device to process different pilot types through specialized, optimized routines rather than attempting to handle all pilots uniformly, thereby managing complexity while supporting multiple pilots.
Solution Approach 2:
The patent introduces heterogeneous pilots as an intermediary between the conventional reference signal framework and the requirements for supporting multiple advanced features. These heterogeneous pilots act as a bridge that enables multiple pilot transmissions without directly conflicting with the primary information-bearing signal resources, while their distinct characteristics provide the receive-device with clear identification and processing cues.
3Device complexity
If pilots are transmitted using the same resources as the primary information-bearing signal, then the resource utilization is simplified, but the interference between pilots and useful data increases
Solution Approach 1:
The patent applies local quality by giving heterogeneous pilots distinct signal structure characteristics that differ from the primary information-bearing signal in specific local aspects (waveform type, resource element pattern, modulation scheme). This local differentiation allows the receive-device to easily distinguish and separately process pilots and data, minimizing interference while maintaining relatively simple overall resource allocation. The heterogeneous pilots occupy the same time-frequency resources but are distinguishable through their local signal characteristics.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach allows for efficient transmission of multiple pilots with zero resource penalty, minimizing interference with useful data and enhancing network capacity, thereby enabling the full realization of advanced features in LTE networks.
Implementation Method 1
a wireless network with OFDM-based RAT uses spread-spectrum signals for heterogeneous pilots
Implementation Method 2
the wireless network uses an orthogonal family of spread-spectrum signals to provide for a multitude of heterogeneous pilots
Data Source
AI summary
Large-dimension MIMO and multipoint broadcasting in new generation of wireless networks create high demand for various types of pilots in transmission signals for channel estimation, data demodulation, synchronization, etc. More pilots, as in existing networks, use more resources and thus diminish the network capacity. Methods and apparatus of heterogeneous pilots are disclosed. A heterogeneous pilot has its own signal characteristics that are different from the primary information-bearing signals in the network. Heterogeneous pilots can be spread-spectrum signals in an OFDM-based wireless network. Heterogeneous pilots use no network resources, and can be as many as desired, and can be designed to have versatile utilities. Also described are methods and apparatus of heterogeneous pilot cancellation that minimizes the interference of heterogeneous pilots on the primary information-bearing signals. Applications of the described methods and apparatus include OFDM-based wireless cellular networks, such as LTE-advanced and Wireless LAN.