Synchronized Broadcast Transmissions Using Common PN Codes
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Solution Overview
Problem
Conventional broadcast/multicast transmissions in wireless communication systems face interference issues due to multiple transmitters using unique spreading codes, degrading reception quality and data rate, necessitating improved interference reduction and flexibility between broadcast and unicast transmissions.
Innovation Solution
Implementing a synchronized broadcast transmission scheme where multiple transmitters use the same waveform or modulation, such as a common Pseudorandom Noise (PN) code or Orthogonal Frequency Division Multiplexing (OFDM), to treat transmissions as artificial multipath components, allowing receivers to improve signal reception with equalization techniques.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple Base Stations transmit broadcast/multicast content using unique spreading codes, then each transmitter can be identified, but interference is caused that degrades reception quality and data rate
Solution Approach 1:
The patent merges multiple broadcast/multicast transmissions from different Base Stations into a synchronized transmission using the same spreading code and waveform. By combining these transmissions in time and frequency, the system transforms interfering signals into constructive additions, improving reception quality without requiring unique spreading codes for each transmitter
Solution Approach 2:
The patent changes the transmission parameters by synchronizing the timing and frequency of broadcast/multicast transmissions across multiple Base Stations and using identical spreading codes. This parameter alignment converts the traditional code-division approach into a time-synchronized approach, eliminating interference while maintaining transmitter identification through other means
2Reliability
If synchronized broadcast transmission with common spreading code is used, then interference is minimized and reception quality improves, but flexibility between broadcast/multicast and unicast transmissions may be reduced
Solution Approach 1:
The patent segments the transmission resources by dedicating specific time slots and frequency resources to synchronized broadcast/multicast transmissions, while other resources remain available for unicast transmissions. This segmentation allows the system to maintain the benefits of synchronized broadcasting while preserving flexibility for other transmission types through resource allocation
Data Source
AI summary
Synchronized broadcast transmits a same broadcast content using a same waveform from multiple transmitters. Transmitters each apply a same spreading code for broadcast transmissions. In a spread-spectrum communication system having a time division multiplexed forward link, a synchronized broadcast transmission is inserted into a broadcast slot. One embodiment employs an Orthogonal Frequency Divisional Multiplex (OFDM) waveform for the synchronized broadcast. An OFDM receiver is then used to process the received synchronized broadcast transmission. An alternate embodiment implements a broadcast Pseudo-random Noise (PN) code for use by multiple transmitters. An equalizer is then employed to estimate the synchronized broadcast transmission.