Abstract— This paper introduces a multiple access scheme called CDMA/PRMA with Piggybacked Reservation, which employ High Altitude Platforms (HAPs) as innovative wireless base station with balanced cell coverage, to achieve higher statistical multiplexing efficiency in the mixed CBR / VBR /ABR (constant, variable, and available bit rate) traffic environment. The idea is to use HAP as mobile communication assisted system with almost equal paths to communication nodes, while reducing signal impairment. The adopted scheme exploits reservation access mechanism. The reservation is assigned in a separate slice of the frame (reservation mini frame) while the rest of the frame is allotted to the communication traffic. The second level exploits the piggybacked reservation with multimode video encoder to deal with the dynamic nature of VBR traffic in order to increase the channel access efficiency. The expediency of the adopted schemes is insured through the simulation of an isolated cell environment. The obtained results indicated that, a substantial increase in the number of heterogeneous users is attained within the intended QoS level.