Throughput Maximization in Wireless Communications Systems
Current theory tells us the ultimate throughput, or ergodic capacity, of an idealized communications system. The ergodic capacity is achieved in idealized systems by using codewords that are infinitely long and thus averaged over an infinite number of instances of the fading channel. Practical systems have a strict coding delay constraint: the codewords used must have finite length and therefore span a finite number of instances of the fading channel. In such systems, ergodic capacity is unattainable. This invention maximizes the throughput of practical delay-constrained systems, where the ergodic capacity measure does not accurately measure the actual performance.Advantages Rather than trying to achieve ergodic capacity, practical systems should try to achieve the maximum throughput for the system at hand. This invention predicts the maximum performance for the hardware and other system constraints at hand (i.e. number of transmit and receive antennas, delay constraints, power limitations, etc.). Significant gains in end-to-end throughput can be achieved over what is commonly done in practice today.
Potential Applications This invention can be used in any communication system where the channel is random, including wireless systems affected by fading channels. The two most practical systems are considered, though it can be used for other systems. The first is when only the communications receiver knows the condition of the fading channel. In this model, the transmitter typically sends data with constant power. The second is when both transmitter and receiver know the condition of the channel. In this situation, the transmitter can perform power control and vary the power based on the channel condition.
There are many applications for this invention. Virtually all wireless systems are affected by fading channels and therefore outage events. . WiFi networks . 802.11 wireless networks . 802.16 broadband wireless networks . 802.15 personal area networks . Satellite communications . Cellular networks � 2G, 3G, 4G and beyond
Inventor(s): Richard Baraniuk
Type of Offer: Licensing
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