In this letter, we propose that directional antennas, combined with power management, be incorporated to reduce intersystem interference in a shared band overlaid high altitude platform station (HAPS)-terrestrial code division multiple access (CDMA) system. To eliminate the HAPS to terrestrial interference, the HAPS is accessed only via directional antennas under the proposed scheme. By doing so, the uplink power to the HAPS can accordingly be increased, so that the terrestrial to HAPS interference is also effectively suppressed.

It is well known that deploying a proxy at the boundary of wireless networks and the Internet is able to improve the performance of transmission control protocol (TCP) over wireless links. Snoop protocol, acting like a transport layer proxy, performs local retransmissions for packets corrupted by wireless channel errors. In this letter, an improvement for the Snoop protocol is proposed to shorten the time spent on local recovery by sending extra copies in every local retransmission attempt. This enables TCP to quickly return to normal, effectively eliminating several of the problems that may cause throughput degradation.

A systematic method for connection-wise end-to-end delay analysis in asynchronous transfer mode (ATM) networks is proposed. This method consists of the followings: (i) per-stream nodal analysis; (ii) output processes characterization; and (iii) moment matching scheme. Following our previous work, we employ H-MMPPs/Slotted D/1 to model ATM queues. Each virtual connection (VC) in ATM networks can be regarded as a tandem configuration of such queues. In [1], the per-stream analytical results for such an H-MMPPs/Slotted D/1 queue have been provided. In this paper, not only the composite output process is exactly characterized, but also the component in an output process that corresponds to a specific traffic stream is approximated via a decomposition scheme. A moment matching scheme to emulate the per-stream output process as a two-state MMPP is further proposed. Through moment matching, we can then approximate the connection-wise end-to-end delay by recursively performing the nodal performance analysis. The connection-wise end-to-end delay is crucial to network resource decision or control problems such as call admission control (CAC) and routing.