Device-to-device (D2D) networks are expected to play a number of roles, such as increasing frequency spectrum efficiency and improving throughput at hot-spots. In this paper, our interest is on the potential of D2D on reducing delivery latency. To enable fast D2D network forming, quick device discovery is essential. For quickening device discovery, we propose a method of defining and using common channel and group channels so as to avoid the channel scan uncertainty faced by the conventional method. Rules for using the common channel and group channels are designed. We evaluate and compare the discovery performance of the proposed method with conventional method by using the superframe structure defined in IEEE 802.15.8 and a general discovery procedure. IEEE 802.15.8 is a standard under development for fully distributed D2D communications. A Netlogo simulator is used to perform step by step MAC simulations. The simulation results verify the effectiveness of the proposed method.

W-CDMA (Wideband-CDMA) is expected to play a significant role in the radio access technology of third-generation mobile telecommunication systems. In second-generation systems, voice traffic from each user has been transmitted mainly via the dedicated transport (radio) channel. In addition, the third-generation systems will efficiently accommodate data traffic based on packet transmission in the shared common transport channel. Therefore, data traffic can be transmitted via one of two types of data channels: i.e., dedicated channels or common channels. However, the channel selecting/switching scheme has not been standardized; thus, system architectures and algorithms of channel-switching schemes in the RNC (Radio Network Controller) are dependent on its vendors, and network operators must determine the parameter settings related to channel selection. In this paper, we will deal with aspects of the architecture in detail, and propose possible algorithms for channel selecting/switching for fundamental reference systems which meet the specifications of the RNC. We will then evaluate our algorithms by means of simulations, and discuss the impact of parameter settings on performance, in terms of packet loss probability and utilization of dedicated channels.

This paper investigates transmission power control for packet transmissions by using code division multiplexing (CDM) in the downlink common (shared) channel of CDMA cellular packet systems and proposes a transmission power control scheme to improve throughput performance and geographical fairness of communication services. In the proposed scheme, downlink transmission power is controlled based on the signal-to-interference ratio predicted at mobile stations. Throughput performance and transmission delay are evaluated under perfect power control conditions. Simulation results show that by using site diversity technique the proposed scheme improves the downlink throughput for light load conditions and geographical fairness for all offered channel loads under both non-fading and fading environments.

This paper describes key technologies for implementing ATM internode signalling. The reliability of a multimedia handling network can be improved by setting multiple virtual paths(VPs)between two nodes and setting signalling links over each internode VP. A software structure appropriate for handling the signalling protocol(MTP3b)within this framework is proposed. We also propose a cost-effective and reliable way to set a signalling route between a node and the service control point(SCP), based on the associate mode structure. Evaluation by implementing a node system shows that it requires only 15% more dynamic program steps for one sending/receiving sequence of the VP signalling than the existing method for circuit-related information. Thus, we could attain highly reliable and cost-effective signalling for ATM multimedia networks.

This paper proposes the signaling network deployment for mobile networks with a goal of reducing the signaling cost and time to set up calls. In this deployment, we solve the heavy concentration of signaling traffic resulting from the centralized database used in current mobile networks. The solution exploits the features of the distributed databases, data partition, locality of mobile users, and Common Channel Signaling System No.7 (CCSS No.7) network architectures. We assume the area served by the mobile network is partitioned into a few zones. There is a database associated with each zone. A numbering database strategy is proposed in this paper for the mobiles to register at some specific nearby databases according to their mobile identification numbers. Thus, a calling party can directly locate the called party by the mobile identification number he/she dialed. This method can reduce over 95% of the location-updating cost and 70% of the location-tracking cost under a general sumulation model. We also present the implementation considerations of this strategy. This implementation is an enhancement of the routing function of the Signaling Connection Control Part in CCSS No.7 protocol stacks. With few modifications on current mobile networks, the proposed strategy can obtain very excellent results.