MUROS Baseband Modulation for GSM Channel Capacity
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Solution Overview
Problem
Current radio communication networks face challenges in increasing channel capacity, particularly due to asymmetrical data and voice traffic demands, leading to wasted resources and call drops, and interference issues from co-channel and adjacent channel interferences.
Innovation Solution
The implementation of Downlink Advanced Receiver Performance (DARP) with Single-Antenna Interference Cancellation (SAIC) and Blind Interferer Cancellation (BIC) methods, which allow for the suppression of co-channel and adjacent-channel interferences, enabling more efficient use of resources and supporting multiple simultaneous calls on the same channel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If more traffic channels are allocated to meet increasing data throughput demand, then channel capacity increases, but network resources are depleted and more base stations are required
Solution Approach 1:
The patent combines multiple users' data streams into a single traffic channel by multiplexing their encoded data sequences. The base station transmits composite signals containing data from multiple users over shared time slots and frequencies, thereby increasing channel capacity without requiring additional physical network resources or base stations.
Solution Approach 2:
The patent introduces signal processing dimensions through sophisticated modulation schemes (QPSK, 8-PSK, 16-QAM) and multi-user detection techniques. By operating in signal space rather than physical resource space, the system achieves higher capacity through dimensional expansion in the signal domain, allowing more users to share the same physical channel.
2Reliability
If UL resources are allocated for new voice calls while DL resources are unavailable, then call setup is blocked, but UL resources remain wasted
Solution Approach 1:
The patent performs preliminary resource pairing checks before call setup by monitoring both UL and DL resource availability in advance. The base station pre-identifies available downlink time slots and frequencies, and only allocates uplink resources when corresponding downlink resources are confirmed available, preventing wasted UL allocations and ensuring call setup success.
Solution Approach 2:
The system implements feedback mechanisms where the base station continuously monitors resource utilization and dynamically adjusts resource allocation decisions. This feedback loop allows the network to recognize when DL resources become available and promptly pair them with waiting UL resources, reducing waste and improving call setup reliability.
3Productivity
If mobile stations operate in multi-timeslot mode to increase data throughput, then data rate improves, but time available for scanning neighbor cells and monitoring decreases
Solution Approach 1:
The patent segments the monitoring and scanning functions from the data reception functions by introducing dedicated synchronization signals and reference signals within the multi-timeslot structure. This allows mobile stations to perform cell scanning and monitoring during specific designated time intervals without interrupting data throughput in other time slots, thereby maintaining both high productivity and adequate monitoring time.
4Productivity
If co-channel and adjacent-channel frequencies are used to increase capacity, then more users can be served, but interference from other cells increases
Solution Approach 1:
The patent converts interference from other cells into useful signal components by implementing interference cancellation techniques. The base station detects and estimates interfering signals from adjacent and co-channel frequencies, then subtracts these estimated interference components from the received signal, thereby recovering the desired signal and enabling capacity expansion using frequencies that would otherwise be too interfered.
Solution Approach 2:
The patent introduces sophisticated signal processing algorithms as intermediaries between the transmitted signal and the received signal. These algorithms include equalization, interference estimation, and cancellation techniques that mediate the effect of interference, allowing the system to operate in high-interference environments and utilize more frequency resources for increased capacity.
Data Source
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AI summary
The present patent application improves DARP by allowing multiple users on one time slot (MUROS). It comprises means, instructions and steps for combining two signals. In one example, it comprises.at least one baseband modulator, a plurality of amplifiers where the signals are multiplied by a gain; at least one combiner operably connected to the amplifiers where the signals are combined; and a phase shifter where one of the signals is phase shifted with respect to the other signal. In another example; the apparatus further comprises a phase shifter operably connected to the at least one baseband modulator to provide a p/2 phase shift between the two signals. In another example, the at least one baseband modulator comprises a BPSK baseband modulator on an I axis and a BPSK baseband modulator on a Q axis.