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.
Citations
More filters
02 Nov 2003
TL;DR: This paper proposes strategies to maintain cache data consistency, which are, based on updating frequency of data items, to broadcast dynamically using variant period, to Broadcast updating messages instead of invalidation messages, and to use substitution strategy based on semantically cached data units.
Abstract: In mobile database, in order to reduce the contention of limited network bandwidth by mobile computers and improve availability of local data, frequently, and used data are cached locally How to effectively maintain cache consistency is a hot research topic In this paper, we propose strategies to maintain cache data consistency, which are, based on updating frequency of data items, to broadcast dynamically using variant period, to broadcast updating messages instead of invalidation messages, to use substitution strategy based on semantically cached data units, to maintain cache consistent based on historical report after mobile computer reconnects Finally we analyze performance of the strategies
17 citations
TL;DR: This paper discusses the power conservative indexing techniques for managing multi-attribute data broadcast on wireless channels, and shows that the signature and hybrid methods are superior to the index tree method.
Abstract: In this paper, we discuss the power conservative indexing techniques for managing multi-attribute data broadcast on wireless channels. These indexing techniques, namely, index tree, signature and hybrid, aim at improving the battery power consumption of mobile clients. By taking into account the broadcast management factors such as clustering and scheduling, these three indexing schemes may significantly reduce tune-in time while maintaining a reasonable access time. Cost models for single and multi-attribute query processing are developed. Our performance evaluation shows that the signature and hybrid methods are superior to the index tree method.
17 citations
Cites methods from "Energy-efficient caching for wirele..."
...In this paper, we investigate the issues and methods for wireless data broadcast services which facilitate multiattribute data access....
[...]
TL;DR: A new cache invalidation scheme, called Broadcast-Based Group Invalidation (BGI), is presented that retains the benefits of caching while avoiding unnecessary transmissions (which translates to energy saving, better channel utilization, and lower costs).
16 citations
TL;DR: The proposed OBS is inspired by an analytical analysis for a server-based Poll-Each-Read and a revised Call-Back and provides an upper bound for effective hit ratio and a lower bound for communication cost.
Abstract: Cache can be used for mobile devices to reduce the usage of limited bandwidth in wireless networks. Ideally, frequently accessed and infrequently updated data items should be cached and infrequently accessed and frequently updated data items should be evicted or not cached at all. Most of the existing cache replacement policies adopt only access information so that frequently updated data items are also cached. As a remedy, we propose a cache replacement policy, called On-Bound Selection (OBS), that uses both data access and update information. The proposed OBS is inspired by an analytical analysis for a server-based Poll-Each-Read (SB-PER) and a revised Call-Back (R-CB). The OBS provides an upper bound for effective hit ratio and a lower bound for communication cost. The proposed scheme is evaluated and compared with a least frequently used (LFU) replacement policy through extensive simulations. Simulation results show that the OBS outperforms LFU in terms of both effective hit ratio and communication cost.
16 citations
Cites background from "Energy-efficient caching for wirele..."
...Cache mechanisms have been introduced to reduce the bandwidth usage of wireless channels [3], [7], [8], [13], [15], [20], [27], [29]....
[...]
01 Jan 1998
TL;DR: An overview of energy-conserving (EC) access protocols designed for mobile computing and communications applications, and significant contributions to this rapidly expanding area are presented.
Abstract: Accelerating consumer interest and mushrooming applications for portable networked devices are driving the demand for the optimization of their functions and components. Portability also necessitates reliance on small, self-contained and therefore limited-life power sources such as batteries, making power-management critical to a successful and wide-spread deployment of these new mobile devices. Meanwhile, communications capabilities are fast becoming standard functions on most types of computing devices. Yet, radio frequency communications activities consume the most power of a portable device, second only to the display functions. The importance of communications access protocols specifically designed to conserve available on-board limited energy is, however, just beginning to be addressed in literature. In this paper, we provide an overview of energy-conserving (EC) access protocols designed for mobile computing and communicationsapplications, and present significant contributions to this rapidly expanding area. We also develop fundamental classifications for EC-protocols, enabling meaningful comparisons between various approaches. We present results comparing the performances of some of the EC-protocols.
15 citations
Cites background from "Energy-efficient caching for wirele..."
...Additionally, there have been significant research efforts specifically targeting energy-conservation for mobile devices, such as rescheduling CPU clock speeds according to operating loads vis-a-vis available energy [40, 29, 42], dynamic hard-disk spin-down algorithms [21], and cache consistency in the presence of receiver sleep-times [41]....
[...]
References
More filters
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