Energy-efficient caching for wireless mobile computing
IBM1
26 Feb 1996-pp 336-343
TL;DR: An energy-efficient cache invalidation method, called GCORE (Grouping with COld update-set REtention), that allows a mobile computer to operate in a disconnected mode to save the battery while still retaining most of the caching benefits after a reconnection is presented.
Abstract: Caching can reduce the bandwidth requirement in a mobile computing environment. However, due to battery power limitations, a wireless mobile computer may often be forced to operate in a doze (or even totally disconnected) mode. As a result, the mobile computer may miss some cache invalidation reports broadcast by a server, forcing it to discard the entire cache contents after waking up. In this paper, we present an energy-efficient cache invalidation method, called GCORE (Grouping with COld update-set REtention), that allows a mobile computer to operate in a disconnected mode to save the battery while still retaining most of the caching benefits after a reconnection. We present an efficient implementation of GCORE and conduct simulations to evaluate its caching effectiveness. The results show that GCORE can substantially improve mobile caching by reducing the communication bandwidth (or energy consumption) for query processing.
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TL;DR: A strategy of maintainning cache consistency in wireless mobile environments is proposed, which adds a validation server (VS) into the GPRS network, utilizes the location information of mobile terminal in SGSN located at G PRS backbone, just sends invalidation information to mobile terminal which is online in accordance with the cached data.
Abstract: In this paper, we propose a strategy of maintainning cache consistency in wireless mobile environments, which adds a validation server (VS) into the GPRS network, utilizes the location information of mobile terminal in SGSN located at GPRS backbone, just sends invalidation information to mobile terminal which is online in accordance with the cached data, and reduces the information amount in asynchronous transmission. This strategy enables mobile terminal to access cached data with very little computing amount, little delay and arbitrary disconnection intervals, and excels the synchronous IR and asynchronous state (AS) in the total performances.
1 citations
06 Dec 2004
TL;DR: A unified approach for QoS provisioning in cellular networks is proposed to provide improved and predictable performance, and an aggregate cache management scheme and an information search algorithm for IMANETS are proposed to improve the data accessibility and communication performance.
Abstract: With the increasing use of wireless networks as a ubiquitous communication infrastructure, design of efficient wireless networks has become a recent research focus. In addition, growing interest in accessing the wired network or Internet services anytime and anywhere has driven the developments of mobile ad hoc networks (MANETS), which can be used in many realistic applications. The critical design issues for wireless and mobile networks include provisioning of seamless communication with Quality-of-Service (QoS) guarantees, high service accessibility, reliable data transfer, and high communication performance. However, limited bandwidth, user mobility, and changing network topology make the design space much more complex and challenging. The overall thesis of this proposal is to design and analyze wireless and mobile networks that can provide QoS guarantees and high communication performance. In particular, we propose to study four related research issues in this proposal. First, a unified approach for QoS provisioning in cellular networks is proposed to provide improved and predictable performance. Second, we investigate the design of Internet based mobile ad hoc networks (IMANETS) for providing universal data accessibility. In the context, we propose an aggregate cache management scheme and an information search algorithm for IMANETS. These two schemes are proposed to improve the data accessibility and communication performance. Next, since mobility of MTs incurs wireless link disconnection and change of network topology, we plan to investigate an adaptive aggregate caching technique for partitionable IMANETS. Finally, since updating a cached or replicated data item is a critical issue for supporting caching in mobile wireless networks, we plan to develop an efficient cache invalidation strategy. We plan to integrate the caching techniques to develop a comprehensive simulation testbed for IMANETS and conduct detailed performance analysis.
1 citations
01 Apr 1997
TL;DR: This paper proposes and studies three strategies that allow clients to repeatedly toggle between doze mode and active mode until the desired objects are obtained and demonstrates that the proposed schemes are energy efficient without sacrificing on the average access times of object retrievals.
Abstract: Existing work on demand-driven-based wireless environments has largely focused on energyefficient caching strategies. While these schemes minimize the number of uplink requests (and hence conserve energy), they are still not adequate as clients must continue to monitor the broadcast for data that is not found in the cache or has been invalidated. Other work on disseminating data via periodic broadcasting of the data file has developed techniques that organize data to allow clients to selectively tune to the desired portion of the broadcast. Such schemes, unfortunately, cannot be applied to demand-driven-based context because demand-driven data cannot be predetermined. In this paper, we study the issue of selective tuning in a demand-driven-based environment. We propose and study three strategies that allow clients to repeatedly toggle between doze mode and active mode until the desired objects are obtained. One of the strategies is stateful-based in the sense that the server is aware of the schedule of doze-ofl/awake time determined by the clients. The other two strategies are stateless-based approaches where the clients’ schedules of doze-off/awake time depend on cues broadcast by the server. We conducted a performance study and our results demonstrate that the proposed schemes are energy efficient without sacrificing on the average access times of object retrievals. Furthermore, our results show that none of the algorithms is superior in all cases.
1 citations
Dissertation•
01 Jan 2005TL;DR: This dissertation designs and analyzes a Scalable Asynchronous Cache Consistency Scheme (SACCS) for single cell wireless cellular networks and proposes an efficient algorithm, called Update Propagation Through Replica Chain (UPTReC), in decentralized and unstructured P2P networks to provide weak file consistency.
Abstract: With the tremendous growth of applications in wireless mobile and Peer-to-Peer (P2P) networks, significant research efforts have been made to improve the quality of service. Caching and replicating frequently used data objects or files in user's local buffers are popular mechanisms to effectively reduce the communication bandwidth requirement and thus improve the overall system performance. However, the frequent disconnections of users make data consistency a difficult task in wireless mobile and P2P networks.
In this dissertation, we design and analyze a Scalable Asynchronous Cache Consistency Scheme (SACCS) for single cell wireless cellular networks. SACCS is a highly scalable, efficient, and low complexity scheme and works well in error-prone wireless mobile environments. Analytical results indicate that SACCS provides very good cache consistency in error-prone wireless environments. Comprehensive simulation results show that SACCS offers more than 50% performance gain than that of existing Timestamp (TS) and Asynchronous Stateful (AS) schemes; We also propose Dynamic SACCS (DSACCS) for multi-cell mobile environments. To the best of our knowledge, DSACCS is the first cache consistency scheme that optimizes cache performance in multi-cell mobile environments.
In P2P networks, some files are heavily replicated to enhance their availability and reduce the search cost. With the dramatic growth in P2P applications dealing with dynamic files, file updates and the file consistency maintenance become critical. To effectively propagate update information to the replica peers, we propose an efficient algorithm, called Update Propagation Through Replica Chain (UPTReC), in decentralized and unstructured P2P networks to provide weak file consistency. To provide strong file consistency, we develop another algorithm, called file Consistency Maintenance through Virtual servers (CMV). In CMV, each dynamic file has a virtual server and any file update must be accepted through the virtual server to maintain one copy serializability of the file. To the best of our knowledge, CMV is the first strong file consistency algorithm for decentralized and unstructured P2P networks. Our simulation results show that UPTReC algorithm outperforms other existing algorithms, and CMV is an efficient file consistency algorithm with very low overhead messages.
1 citations
Cites background from "Energy-efficient caching for wirele..."
...Stateless schemes [4] [8] [28] [30] [39] [57] [64] [68] periodically broadcast IRs to MUs and employ simple database management in the BS, but their scalability and ability to support disconnection are poor....
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...In the stateless schemes [4] [8] [10] [28] [30] [39] [57] [64] [68], the server is unaware of the MUC’s content....
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...As mentioned in the last chapter, existing stateless cache consistency schemes for wireless mobile networks [4] [8] [28] [30] [39] [57] [64] [68] are not scalable, whereas the stateful schemes [31] [9] entail complex data management tasks in the server database....
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...A validation check scheme is proposed in [64] to deal with long sleep-wakeup patterns....
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References
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622 citations
Proceedings Article•
01 Jan 1995
TL;DR: In this paper, a taxonomy of different cache invalidation strategies and study the impact of client's disconnection times on their performance is presented, and the authors determine that for the units which are often disconnected (sleepers) the best cache invalidization strategy is based on signatures previously used for efficient file comparison.
Abstract: In the mobile wireless computing environment of the future a large number of users equipped with low powered palm-top machines will query databases over the wireless communication channels. Palmtop based units will often be disconnected for prolonged periods of time due to the battery power saving measures; palmtops will also frequencly relocate between different cells and connect to different data servers at different times. Caching of frequently accessed data items will be an important technique that will reduce contention on the narrow bandwidth wireless channel. However, cache invalidation strategies will be severely affected by the disconnection and mobility of the clients. The server may no longer know which clients are currently residing under its cell and which of them are currently on. We propose a taxonomy of different cache invalidation strategies and study the impact of client's disconnection times on their performance. We determine that for the units which are often disconnected (sleepers) the best cache invalidation strategy is based on signatures previously used for efficient file comparison. On the other hand, for units which are connected most of the time (workaholics), the best cache invalidation strategy is based on the periodic broadcast of changed data items.
509 citations
24 May 1994
TL;DR: A taxonomy of different cache invalidation strategies is proposed and it is determined that for the units which are often disconnected (sleepers) the best cache invalidations strategy is based on signatures previously used for efficient file comparison, and for units which is connected most of the time (workaholics), the best Cache invalidation strategy isbased on the periodic broadcast of changed data items.
Abstract: In the mobile wireless computing environment of the future a large number of users equipped with low powered palm-top machines will query databases over the wireless communication channels. Palmtop based units will often be disconnected for prolonged periods of time due to the battery power saving measures; palmtops will also frequencly relocate between different cells and connect to different data servers at different times. Caching of frequently accessed data items will be an important technique that will reduce contention on the narrow bandwidth wireless channel. However, cache invalidation strategies will be severely affected by the disconnection and mobility of the clients. The server may no longer know which clients are currently residing under its cell and which of them are currently on. We propose a taxonomy of different cache invalidation strategies and study the impact of client's disconnection times on their performance. We determine that for the units which are often disconnected (sleepers) the best cache invalidation strategy is based on signatures previously used for efficient file comparison. On the other hand, for units which are connected most of the time (workaholics), the best cache invalidation strategy is based on the periodic broadcast of changed data items.
454 citations
24 May 1994
TL;DR: This work describes two methods, (1,m) Indexing and Distributed Indexing, for organizing and accessing broadcast data and demonstrates that the proposed algorithms lead to significant improvement of battery life, while retaining a low access time.
Abstract: We consider wireless broadcasting of data as a way of disseminating information to a massive number of users. Organizing and accessing information on wireless communication channels is different from the problem of organizing and accessing data on the disk. We describe two methods, (1,m) Indexing and Distributed Indexing, for organizing and accessing broadcast data. We demonstrate that the proposed algorithms lead to significant improvement of battery life, while retaining a low access time.
421 citations
TL;DR: The author begins by discussing the background, defining key terms and showing how wireless information systems can be viewed as a natural evolution of computing's relentless march toward greater distribution and ubiquity of access.
Abstract: The author begins by discussing the background, defining key terms and showing how wireless information systems can be viewed as a natural evolution of computing's relentless march toward greater distribution and ubiquity of access. Next, the research issues faced by designers of wireless information systems are detailed, and some large-scale engineering challenges for such designers are presented. The existing cellular system architecture, evolved from telephony, is compared with an alternative architecture more closely integrated with a computer networking view of wireless systems. Existing wireless systems are reviewed, and the final section presents the author's summary and conclusions, and charts the future of wireless information systems. >
321 citations