8520040
The embedded software consortium of taiwan
The advancement of semiconductor manufacturing technology makes it practical to place a traditional board-level embedded system on a single chip. The evolvement of system-on-chip (SoC) techniques presents new challenges for integrated circuit designs as well as embedded software and systems. To address these challenges, the Ministry of Education (MOE) of Taiwan has been running the VLSI Circuits and Systems Education Program since 1996. This program adopts a top-down approach by forming six domain-specific, intercollegiate consortia. The Embedded Software (ESW) consortium addresses the challenges of embedded software for SoC systems. This paper first introduces the six-consortium architecture and the organization and programs of ESW. We next describe the embedded software curriculum developed by ESW. This curriculum will later be implemented in most universities and colleges in Taiwan to promote the capabilities of embedded software design and implementations. Finally, we present an execution summary of ESW 2004.
28156768
A VLSI implementation of the blowfish encryption/decryption algorithm
We propose an efficient hardware architecture for the Blowfish algorithm [1]. The speed is up to 4 bit/clock, which is 9 times faster than a Pentium. By applying operator-rescheduling method, the critical path delay is improved by 21.7%. We have successfully implemented it using Compass cell library targeted at a 0.6 μm TSMC SPTM CMOS process. The die size is 5.7x6.1 mm and the maximum frequency is 50MHz.
195838317
Data path allocation based on bipartite weighted matching
Proposes a graph-theoretic approach for the data path allocation problem. The problem is decomposed into three subproblems: (1) register allocation, (2) operation assignment, and (3) connection allocation. The first two subproblems are modeled as two bipartite weighted matching problems and solved using the Hungarian method. The third subproblem is solved using a greedy method. It is shown that, by taking the other into consideration while solving one, equally satisfactory results can be obtained, regardless of the order in which (1) and (2) are performed. Two programs, LYRA and ARYL, are implemented which solve the subtasks in different orders. For register allocation, the approach is the first one to guarantee minimal use of registers while being able to take the interconnection cost into account. This research has demonstrated that the bipartite weighted matching algorithm is indeed a good solution for the data path allocation problem.<<ETX>>
53235373
Performance-optimal clustering with retiming for sequential circuits
195837942
Optimum and heuristic data path scheduling under resource constraints
An integer linear programming model for the scheduling problem in high-level synthesis under resource constraints is presented. The following applications are considered: multicycle operations with nonpipelined or pipelined function units: mutually exclusive operations: functional pipelining: loop-folding; and scheduling under bus constraint. Besides the model, a new technique, called zone scheduling (ZS), is proposed to solve large-size problems. ZS partitions the distribution graph into several zones and sequentially solves the problems contained. A novel feature of this technique is that it schedules more than one control step at a time, allowing a more global view of a scheduling problem to be taken.<<ETX>>
6763648
An effective methodology for functional pipelining
We address the problem of given a loop behavior, a target initiation interval and resource constraints, scheduling a loop in a pipelined fashion such that the iteration time (turn-around time) is minimized. The iteration time is an important quality measure of a data path design because of its direct correlationship with both the storage and the control costs. Our scheduler starts with performing an As Soon As Possible Pipelined (ASAPp) scheduling without regard to the resource constraint. It then resolves the resource constraint violations, if there are any, by repeatedly rescheduling some operations.
11334904
Call Performance for a PCS Network
It is well known that, due to the mobility of a portable and limited channel availability, calls of portables may not be completed due to being blocked or terminated during the call initiation or the handover process. The characteristics of the call-completion and call-holding times for both a complete call and an incomplete call are of critical importance for establishing the actual billing process in the PCS network. We derive the call-completion probability (hence, call-dropping probability) and the effective call-holding time distributions for complete/incomplete calls with a general cell-residence time and a general call-holding time are analyzed, and general computable formulas are obtained. We show that when call-holding times are Erlang distributed, easy-to-compute formulas for the probability of a call completion and the expected effective call-holding times for both a complete call and an incomplete call can be derived.
7180014
A software architecture for GPRS session management
General packet radio service (GPRS) provides efficient access to the integrated services Internet from wireless networks. When the GPRS-attached mobile station attempts to send or receive data, a packet data protocol (PDP) context shall be established. The GPRS session management (SM) supports the PDP context handling, which consists of PDP context activation, deactivation, and modification procedures. In this paper, we propose an SM software architecture for the serving GPRS support node. Our design goals are to achieve compatibility, modularity, and flexibility. More importantly, our approach can accommodate the design of the SM software architecture for third-generation wireless networks. Copyright © 2001 John Wiley & Sons, Ltd.
2805042
A new random walk model for PCS networks
This paper proposes a new approach to simplify the two-dimensional random walk models capturing the movement of mobile users in personal communications services (PCS) networks. Analytical models are proposed for the new random walks. For a PCS network with hexagonal configuration, our approach reduces the states of the two-dimensional random walk from (3n/sup 2/+3n-5) to n(n+1)/2, where n is the layers of a cluster. For a mesh configuration, our approach reduces the states from (2n2-2n+1) to (n/sup 2/+2n+4)/4 if n is even and to (n/sup 2/+2n+5)/4 if n is odd. Simulation experiments are conducted to validate the analytical models. The results indicate that the errors between the analytical and simulation models are within 1%. Three applications (i.e., microcell/macrocell configuration, distance-based location update, and GPRS mobility management for data routing) are used to show how our new model can be used to investigate the performance of PCS networks.
42550314
Performance of CDPD with Timed Hop and Forced Hop
Cellular Digital Packet Data (CDPD) offers mobile users access to a low-cost, ubiquitous, wireless data network. CDPD can be overlaid on existing AMPS analog cellular systems and share their infrastructure equipment on a non-interfering basis. To prevent interference with the voice activities, CDPD performs forced hop to a channel stream when a voice request is about to use the RF channel occupied by that channel stream. In addition, several timers and system parameters are defined in CDPD to ensure that the normal AMPS activities are not affected by CDPD. This article investigates how the channel selection algorithms, the timers and other parameters affect the performance of AMPS/CDPD systems. Specifically, we study the trade-off between mean CDPD channel holding time and voice incompletion probability. Our study indicates that if AMPS exercises the most-idle channel selection algorithm and CDPD exercises the least-idle channel selection algorithm, then the largest mean CDPD channel holding time is expected. On the other hand, if AMPS exercises the least-idle channel selection algorithm, then the smallest voice incompletion probability is expected.
14820349
Per-user checkpointing for mobility database failure restoration
This paper studies the failure restoration of mobility database for Universal Mobile Telecommunications System (UMTS). We consider a per-user checkpointing approach for the home location register (HLR) database. In this approach, individual HLR records are saved into a backup database from time to time. When a failure occurs, the backup record is restored back to the mobility database. We first describe a commonly used basic checkpoint algorithm. Then, we propose a new checkpoint algorithm. An analytic model is developed to compare these two algorithms in terms of the checkpoint cost and the probability that an HLR backup record is obsolete. This analytic model is validated against simulation experiments. Numerical examples indicate that our new algorithm may significantly outperform the basic algorithm in terms of both performance measures.