The SoftPHY Abstraction: from Packets to Symbols in Wireless Network Design
At ever-increasing rates, we are using wireless systems to communicatewith others and retrieve content of interest to us. Current wirelesstechnologies such as WiFi or Zigbee use forward error correction todrive bit error rates down when there are few interferingtransmissions. However, as more of us...
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2008
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| Online Access: | http://hdl.handle.net/1721.1/41857 |
| _version_ | 1811089390804402176 |
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| author | Jamieson, Kyle |
| author2 | Hari Balakrishnan |
| author_facet | Hari Balakrishnan Jamieson, Kyle |
| author_sort | Jamieson, Kyle |
| collection | MIT |
| description | At ever-increasing rates, we are using wireless systems to communicatewith others and retrieve content of interest to us. Current wirelesstechnologies such as WiFi or Zigbee use forward error correction todrive bit error rates down when there are few interferingtransmissions. However, as more of us use wireless networks toretrieve increasingly rich content, interference increases inunpredictable ways. This results in errored bits, degradedthroughput, and eventually, an unusable network. We observe that thisis the result of higher layers working at the packet granularity,whereas they would benefit from a shift in perspective from wholepackets to individual symbols.From real-world experiments on a 31-node testbed of Zigbee andsoftware-defined radios, we find that often, not all of the bitsin corrupted packets share fate. Thus, today's wireless protocolsretransmit packets where only a small number of the constituent bitsin a packet are in error, wasting network resources. In thisdissertation, we will describe a physical layer that passesinformation about its confidence in each decoded symbol up to higherlayers. These SoftPHY hints have many applications, one ofwhich, more efficient link-layer retransmissions, we will describe indetail. PP-ARQ is a link-layer reliable retransmission protocolthat allows a receiver to compactly encode a request forretransmission of only the bits in a packet that are likely in error.Our experimental results show that PP-ARQ increases aggregate networkthroughput by a factor of approximately 2x under variousconditions. Finally, we will place our contributions in the contextof related work and discuss other uses of SoftPHY throughout thewireless networking stack. |
| first_indexed | 2024-09-23T14:18:25Z |
| id | mit-1721.1/41857 |
| institution | Massachusetts Institute of Technology |
| last_indexed | 2024-09-23T14:18:25Z |
| publishDate | 2008 |
| record_format | dspace |
| spelling | mit-1721.1/418572019-04-11T03:10:06Z The SoftPHY Abstraction: from Packets to Symbols in Wireless Network Design Jamieson, Kyle Hari Balakrishnan Networks & Mobile Systems 802.11 802.15.4 At ever-increasing rates, we are using wireless systems to communicatewith others and retrieve content of interest to us. Current wirelesstechnologies such as WiFi or Zigbee use forward error correction todrive bit error rates down when there are few interferingtransmissions. However, as more of us use wireless networks toretrieve increasingly rich content, interference increases inunpredictable ways. This results in errored bits, degradedthroughput, and eventually, an unusable network. We observe that thisis the result of higher layers working at the packet granularity,whereas they would benefit from a shift in perspective from wholepackets to individual symbols.From real-world experiments on a 31-node testbed of Zigbee andsoftware-defined radios, we find that often, not all of the bitsin corrupted packets share fate. Thus, today's wireless protocolsretransmit packets where only a small number of the constituent bitsin a packet are in error, wasting network resources. In thisdissertation, we will describe a physical layer that passesinformation about its confidence in each decoded symbol up to higherlayers. These SoftPHY hints have many applications, one ofwhich, more efficient link-layer retransmissions, we will describe indetail. PP-ARQ is a link-layer reliable retransmission protocolthat allows a receiver to compactly encode a request forretransmission of only the bits in a packet that are likely in error.Our experimental results show that PP-ARQ increases aggregate networkthroughput by a factor of approximately 2x under variousconditions. Finally, we will place our contributions in the contextof related work and discuss other uses of SoftPHY throughout thewireless networking stack. 2008-06-05T18:00:27Z 2008-06-05T18:00:27Z 2008-06-03 MIT-CSAIL-TR-2008-031 http://hdl.handle.net/1721.1/41857 Massachusetts Institute of Technology Computer Science and Artificial Intelligence Laboratory 153 p. application/pdf application/postscript |
| spellingShingle | 802.11 802.15.4 Jamieson, Kyle The SoftPHY Abstraction: from Packets to Symbols in Wireless Network Design |
| title | The SoftPHY Abstraction: from Packets to Symbols in Wireless Network Design |
| title_full | The SoftPHY Abstraction: from Packets to Symbols in Wireless Network Design |
| title_fullStr | The SoftPHY Abstraction: from Packets to Symbols in Wireless Network Design |
| title_full_unstemmed | The SoftPHY Abstraction: from Packets to Symbols in Wireless Network Design |
| title_short | The SoftPHY Abstraction: from Packets to Symbols in Wireless Network Design |
| title_sort | softphy abstraction from packets to symbols in wireless network design |
| topic | 802.11 802.15.4 |
| url | http://hdl.handle.net/1721.1/41857 |
| work_keys_str_mv | AT jamiesonkyle thesoftphyabstractionfrompacketstosymbolsinwirelessnetworkdesign AT jamiesonkyle softphyabstractionfrompacketstosymbolsinwirelessnetworkdesign |