Nonuniform phase-shift-key modulation for multimedia transmission in mobile wireless communications

Wireless communication systems are being employed for an increasing number of military and commercial applications. In these systems, the channels from a transmitter to a group of receivers vary due to differences among the channels in attenuation, fading, and interference. Thus, certain receiving terminals have a greater capability than others, in the sense that they have a better channel from the transmitter. For mobile radio systems, the channel conditions change over time. Many existing radio systems do not take advantage of these differences in channel characteristics. Future radio systems will be required to handle a variety of multimedia information with differing quality-of-service requirements. Signaling techniques can be designed that exploit the differences in receiver capabilities and service requirements. In this dissertation, several such techniques for mobile wireless communications are presented and analyzed.;In many wireless communication systems, radios use broadcast or multicast signaling to transmit a message to multiple receivers. Nonuniform phase-shift keying (PSK) can increase the throughput of multicast transmissions by delivering additional information to more-capable receivers along with the multicast message. This additional information can be included with very little loss in performance for the reception of the basic message. This capability for additional throughput can be employed to transmit multimedia messages (e.g., voice and data) to more-capable receivers. Several signaling methods that employ nonuniform PSK are investigated, and the tradeoffs involved in using these methods for multicast signaling are determined. Signaling methods that employ convolutional codes with nonuniform PSK are also considered, and it is shown that the option of using such codes provides even greater flexibility in performance tradeoffs and greater energy efficiency.;Signaling techniques that adapt the transmission to the channel conditions can improve the network throughput. Adaptive signaling methods that employ nonuniform PSK can be used in mobile radio systems, especially those that handle multiple types of multimedia traffic. Examples are given that illustrate how adaptive nonuniform signaling can improve network efficiency, including application to a cellular radio system that employs direct-sequence spread-spectrum multiple access, also known as code-division multiple access (CDMA).