scispace - formally typeset
Search or ask a question
Proceedings ArticleDOI

Energy-efficient caching for wireless mobile computing

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.
Citations
More filters
Journal Article
TL;DR: This paper investigates the broadcasting scheduling over multiple channels for the case where a mobile client might need more than one page and proposes an efficient broadcast scheduling strategy, a hybrid approach, that combines the advantages of page-based and set-based strategies.
Abstract: In this paper, we investigate the broadcasting scheduling over multiple channels for the case where a mobile client might need more than one page (i.e., a query set of data pages). Ke has proposed the SNV (Set-based version-Non-overlap Version) strategy for query set broadcast scheduling in multiple channels. In the SNV strategy, the data pages of the same query set are put together as much as possible, and the strategy tries to avoid scheduling two or more pages of one query set at the same time slot of different channels. However, there are two disadvantages with the SNV strategy: (1) a data page with high access frequency may be scheduled at a time slot near the end of the broadcast cycle, which will result in long access time for the whole query set; (2) it may increase the number of slots in a certain chain, which will result in a waste of bandwidth of the other channels. Therefore, in this paper, we propose an efficient broadcast scheduling strategy, a hybrid approach, to improve these two disadvantages. Basically, our hybrid approach combines the advantages of page-based and set-based strategies. Through our performance analysis and simulation, we show that our hybrid approach requires less total expected delay access time and creates a smaller number of slots and a smaller number of empty slots in one broadcast cycle compared to the SNV strategy.

5 citations


Cites methods from "Energy-efficient caching for wirele..."

  • ...Also, some approaches reduce the access time by caching [2, 3, 7, 18, 33], and nonuniform broadcasting [3, 18, 30, 31], and some reduce the tuning time by indexing [14, 19-21, 29, 33, 35], hashing [19] or using signature [24] techniques, where the tuning time is the amount of time spent by a client listening to the channel....

    [...]

Proceedings ArticleDOI
09 May 2005
TL;DR: It is shown that in theory for any given reconnection pattern, a report with a minimal false invalidation rate can be derived and a method to compose a near-optimal invalidation report is proposed, which is simple and fast.
Abstract: Caching can reduce expensive data transfers and improve the performance of mobile computing. In order to reuse caches after short disconnections, invalidation reports are broadcast to clients to identify outdated items. Detailed reports may not be desirable because they can consume too much bandwidth. On the other hand, false invalidations may set in if the accurate timing of updates is not provided. In this research, we aim to reduce the false invalidation rates of cached items. Based on our analysis, false invalidation rates are closely related to clients' reconnection patterns (i.e., the distribution of the time spans between disconnections and reconnections). We show that in theory for any given reconnection pattern, a report with a minimal false invalidation rate can be derived. For practical uses, we propose to capture the reconnection pattern by sampling and develop a method to compose a near-optimal invalidation report. This method is simple and fast. Experimental results have confirmed that our method is indeed more effective in reducing the false invalidation rate than others.

5 citations

Journal Article
TL;DR: The server in this algorithm broadcasts two kind of messages, asynchronous invalidation report to reduce transaction latency and periodic guide message to avoid the uncertainty of waiting time for the next invalidations.

5 citations

Journal ArticleDOI
TL;DR: The simulation results show that the proposed CCSP scheme improves significantly the cache effectiveness and the network performances, by improving data availability and reducing both overall network load and latencies perceived by end users.
Abstract: In wireless mobile Ad Hoc networks, cooperative cache management is considered as an efficient technique to increase data availability and improve access latency. This technique is based on coordination and sharing of cached data between nodes belonging to the same area. In this paper, we studied the cooperative cache management strategies. This has enabled us to propose a collaborative cache management scheme for mobile Ad Hoc networks, based on service cache providers (SCP), called cooperative caching based on service providers (CCSP). The proposed scheme enabled the election of some SCPs mobile nodes, which receive cache’s summaries of neighboring nodes. Thus, nodes belonging to the same zone can locate easily cached documents of that area. The election mechanism used in this approach is executed periodically to ensure load balancing. We further provided an evaluation of the proposed solution, in terms of request hit rate, byte hit rate and time gains. Compared with other caching management schemes, the simulation results show that the proposed CCSP scheme improves significantly the cache effectiveness and the network performances. This is achieved by improving data availability and reducing both overall network load and latencies perceived by end users.

5 citations


Cites background from "Energy-efficient caching for wirele..."

  • ...The web documents sizes follow heavy-tailed probability distribution [13, 23]....

    [...]

  • ...However, in mobile Ad Hoc networks, nodes belonging to the same geographic area may have similar tasks and share common interest, thus cache replacement strategies that perform replacement individually cannot be suitable [12, 13]....

    [...]

References
More filters
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

Proceedings ArticleDOI
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

Proceedings ArticleDOI
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

Journal ArticleDOI
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

Trending Questions (1)
How to clear browser cache in Robot Framework?

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.