EP1661322A1 - Back-end alignment to avoid sdma ack time-out - Google Patents
Back-end alignment to avoid sdma ack time-outInfo
- Publication number
- EP1661322A1 EP1661322A1 EP04780531A EP04780531A EP1661322A1 EP 1661322 A1 EP1661322 A1 EP 1661322A1 EP 04780531 A EP04780531 A EP 04780531A EP 04780531 A EP04780531 A EP 04780531A EP 1661322 A1 EP1661322 A1 EP 1661322A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- transmissions
- transmission
- electronic device
- predicted
- approximately
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
Links
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W88/00—Devices specially adapted for wireless communication networks, e.g. terminals, base stations or access point devices
- H04W88/02—Terminal devices
- H04W88/06—Terminal devices adapted for operation in multiple networks or having at least two operational modes, e.g. multi-mode terminals
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L1/00—Arrangements for detecting or preventing errors in the information received
- H04L1/12—Arrangements for detecting or preventing errors in the information received by using return channel
- H04L1/16—Arrangements for detecting or preventing errors in the information received by using return channel in which the return channel carries supervisory signals, e.g. repetition request signals
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L1/00—Arrangements for detecting or preventing errors in the information received
- H04L1/12—Arrangements for detecting or preventing errors in the information received by using return channel
- H04L1/16—Arrangements for detecting or preventing errors in the information received by using return channel in which the return channel carries supervisory signals, e.g. repetition request signals
- H04L1/1607—Details of the supervisory signal
- H04L1/1685—Details of the supervisory signal the supervisory signal being transmitted in response to a specific request, e.g. to a polling signal
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L1/00—Arrangements for detecting or preventing errors in the information received
- H04L1/12—Arrangements for detecting or preventing errors in the information received by using return channel
- H04L1/16—Arrangements for detecting or preventing errors in the information received by using return channel in which the return channel carries supervisory signals, e.g. repetition request signals
- H04L1/18—Automatic repetition systems, e.g. Van Duuren systems
- H04L1/1867—Arrangements specially adapted for the transmitter end
- H04L1/188—Time-out mechanisms
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L1/00—Arrangements for detecting or preventing errors in the information received
- H04L1/12—Arrangements for detecting or preventing errors in the information received by using return channel
- H04L1/16—Arrangements for detecting or preventing errors in the information received by using return channel in which the return channel carries supervisory signals, e.g. repetition request signals
- H04L1/18—Automatic repetition systems, e.g. Van Duuren systems
- H04L1/1867—Arrangements specially adapted for the transmitter end
- H04L1/1887—Scheduling and prioritising arrangements
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L27/00—Modulated-carrier systems
- H04L27/26—Systems using multi-frequency codes
- H04L27/2601—Multicarrier modulation systems
- H04L27/2602—Signal structure
- H04L27/261—Details of reference signals
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W16/00—Network planning, e.g. coverage or traffic planning tools; Network deployment, e.g. resource partitioning or cells structures
- H04W16/24—Cell structures
- H04W16/28—Cell structures using beam steering
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W56/00—Synchronisation arrangements
- H04W56/004—Synchronisation arrangements compensating for timing error of reception due to propagation delay
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W74/00—Wireless channel access, e.g. scheduled or random access
- H04W74/02—Hybrid access techniques
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W88/00—Devices specially adapted for wireless communication networks, e.g. terminals, base stations or access point devices
- H04W88/08—Access point devices
Definitions
- a base station may transmit or receive separate signals to or from multiple mobile devices at the same time on the same frequency, provided the mobile devices are located in sufficiently different directions from the base station.
- different signals may be simultaneously transmitted from each of separate spaced-apart antennas so that the combined transmissions are directional, i.e., the signal intended for each mobile device may be relatively strong in the direction of that mobile device and relatively weak in other directions.
- the base station may receive the combined signals from multiple independent mobile devices at the same time on the same frequency through each of separate spaced-apart antennas, and separate the combined received signals from the multiple antennas into the separate signals from each mobile device through appropriate signal processing so that the reception is directional.
- IEEE 802.11 IEEE is the acronym for the Institute of Electrical and Electronic Engineers, 3 Park Avenue, 17th floor, New York, New York
- a base station may transmit different variable-length blocks to different mobile devices at substantially the same time, and then wait for the designated mobile devices to respond with acknowledgments, with each acknowledgment signifying that the respective mobile device received the block.
- processors may refer to any device or portion of a device that processes electronic data from registers and/or memory to transform that electronic data into other electronic data that may be stored in registers and/or memory.
- a “computing platform” may comprise one or more processors.
- wireless and its derivatives may be used to describe circuits, devices, systems, methods, techniques, communications channels, etc., that may communicate data through the use of modulated electromagnetic radiation through a non-solid medium. The term does not imply that the associated devices do not contain any wires, although in some embodiments they might not.
- base station In keeping with common industry terminology, the terms "base station”,
- access point and “AP” may be used interchangeably herein to describe an electronic device that may communicate wirelessly and substantially simultaneously with multiple other electronic devices
- mobile device and “STA” may be used interchangeably to describe any of those multiple other electronic devices, which may have the capability to be moved and still communicate, though movement is not a requirement.
- scope of the invention is not limited to devices that are labeled with those terms.
- spatial division multiple access and SDMA may be used interchangeably.
- these terms are intended to encompass any communication technique in which different signals may be transmitted by a combination of antennas substantially simultaneously from the same device such that the combined transmitted signals result in different signals intended for different devices being transmitted substantially in different directions on the same frequency, and/or techniques in which different signals may be received substantially simultaneously through multiple antennas on the same frequency from different devices in different directions and the different signals may be separated from each other through suitable processing.
- the term "same frequency”, as used herein, may include slight variations in the exact frequency due to such things as bandwidth tolerance, Doppler shift adaptations, parameter drift, etc.
- Two or more transmissions to different devices are considered substantially simultaneous if at least a portion of each transmission to the different devices occurs at the same time, but does not imply that the different transmissions must start and/or end at the same time, although they may.
- two or more receptions from different devices are considered substantially simultaneous if at least a portion of each reception from the different devices occurs at the same time, but does not imply that the different transmissions must start and/or end at the same time, although they may.
- Variations of the words represented by the term SDMA may sometimes be used by others, such as but not limited to substituting "space” for "spatial", or “diversity” for "division". The scope of various embodiments of the invention is intended to encompass such differences in nomenclature. [0012] Fig.
- FIG. 1 shows a diagram of a communications network, according to an embodiment of the invention.
- the illustrated embodiment of an SDMA-based network shows an AP 110 that may communicate with multiple STAs 131-134 located in different directions from the AP, while avoiding acknowledgment timeouts associated with sending different length transmissions to the different STAs.
- AP 110 is shown with four antennas 120 to simultaneously communicate with up to four STAs at a time, other embodiments may have other arrangements (e.g., AP 110 may have two, three, or more than four antennas).
- Each STA may have one or more antennas to communicate with the AP 110.
- the one or more STA antennas may be adapted to operate as omnidirectional antennas, but in other embodiments the one or more STA antennas may be adapted to operate as directional antennas.
- the STAs may be in fixed locations, but in other embodiments at least some of the STAs may be moving during and/or between the communication sequences.
- the AP 110 may be in a fixed location, but in other embodiments the AP 110 may be mobile.
- Fig. 2 shows a timing diagram of a communications sequence involving an AP and two STAs (labeled STAl and STA2), according to an embodiment of the invention. Although the illustrated embodiment only shows two STAs, other embodiments may comprise other quantities of STAs.
- Such sequences may include, but are not limited to, such things as training (communications to derive parameters needed to enable SDMA techniques), poll (request to respond), data (substantive information), acknowledgment (verification that a previous transmission was correctly received), etc.
- training communications to derive parameters needed to enable SDMA techniques
- poll request to respond
- data substantial information
- acknowledgment verification that a previous transmission was correctly received
- the AP may transmit to both STAl and STA2 during time period ti.
- the AP transmits a poll (POLL1) to STAl, requesting a response including data (if any data is available) and an acknowledgment (ACK1) to the POLL1 from STAl.
- the AP transmits a poll (POLL2) to STA2 substantially simultaneously with the poll to STAl, requesting a response including data (if any data is available) and an acknowledgment (ACK2) to the POLL2 from STA2.
- the AP also transmits data to STA2 in addition to POLL2, causing the transmission to STA2 to be longer than the transmission to STAl .
- the transmission to STAl might end sooner than the transmission to STA2, and the immediate response from STAl might not be received by the AP because the AP would still be transmitting to STA2 during that response.
- the AP might subsequently begin listening for the response from STAl, but never receive the response because it had been transmitted too soon.
- the start of the transmission to STAl may be delayed for a predetermined time so that the transmissions to STAl and STA2 both end at approximately the same timej as shown in Fig. 2.
- both STAl and STA2 may respond within a prescribed time after their respective polls and avoid timeout issues, even though the prescribed time may be substantially shorter than the possible difference in the durations of the transmissions from STAl and STA2.
- the illustrated embodiment shows separate timeout periods for each STA that is polled, and the separate timeout periods may have the same or different durations (the same durations are shown). Alternately, a single timeout period may be maintained within which all polled STAs are expected to send an acknowledgment.
- the illustrated embodiment also shows acknowledgment timeout periods that are shorter than the response period t , during which a given STA may deliver an acknowledgment within the timeout period that is separately verifiable from the remaining response (e.g., the acknowledgment may be verified as correctly received by the AP even if the remainder of the response becomes corrupted), but other embodiments may use other techniques (e.g., the acknowledgement timeout period may be as long or longer than time period t 2 , the beginning of any response may be interpreted as an acknowledgment, etc.).
- a response may contain one or more transmissions that are separately verifiable (e.g., using a CRC check).
- STAl and STA2 contain a poll, while only one contains data, but other embodiments may use other techniques. For example: 1) all, some, or none of the transmissions from the AP may contain a poll, 2) all, some, or none of the transmissions from the AP may contain data, 3) alb some, or none of the transmissions from the AP may contain a training request, 4) etc. In various embodiments, any transmissions from the AP to the STAs that have different lengths and that expect acknowledgments from the STAs may use the techniques described herein. [0019] Fig. 3 shows a flow chart of a method of adjusting transmissions to end at approximately the same time, according to an embodiment of the invention.
- a start delay may be calculated for each of the various transmissions, so that if the start of each transmission is delayed by its associated delay time, all the transmissions will end at approximately the same time. The start delay times may be measured from any feasible common reference point.
- the actual transmissions may be started, using the indicated delays in their start times so that the transmissions end at approximately the same time at 360.
- the mobile devices may each respond, and the responses may be received at 370.
- the described process may include calculating and using a delay time for the longest transmission. In some embodiments that match the time allotted for transmission to the length of the longest transmission, calculating and using a delay time for the longest transmission may be eliminated.
- STAl and STA2 may transmit responses to the AP substantially simultaneously.
- these responses each include data and an acknowledgment to the respective poll, but other embodiments may produce other types of responses.
- alb some, or none of the response from a particular STA may contain an acknowledgment
- alb some, or none of the response from a particular STA may contain data
- 3) the existence of any correctly received response may be interpreted as an acknowledgment
- the AP may individually acknowledge these responses substantially simultaneously, as shown.
- ACK1 is shown as the acknowledgment to the response from STAl
- ACK2 is shown as the acknowledgment to the response from STA2.
- a given STA does not receive an acknowledgment within a defined time period, it may assume the response was not correctly received by the AP and may re-transmit the response when polled again.
- Various techniques may be used to set this defined time period.
- the embodiment of Fig. 2 shows an interframe space (IFS).
- IFS interframe space
- Various embodiments may use such time intervals in all, some, or none of the indicated places.
- the IFSs may have uniform duration, or may have different durations according to various criteria.
- time intervals may serve various purposes, for example: 1) to allow for differences in the timing of the AP and various STAs, 2) to allow a time for any needed processing between transmissions and receptions, 3) to allow time for a transceiver to switch between transmit and receive modes, 4) etc.
- the delays in starting times for the transmissions from the base station may be calculated from the interframe space immediately preceding the transmissions. In other embodiments, the delays in starting times for all but the longest transmission may be calculated from the start of the longest transmission.
- Embodiments of the invention may be implemented in one or a combination of hardware, firmware, and software. Embodiments of the invention may also be implemented as instructions stored on a machine-readable medium, which may be read and executed by a computing platform to perform the operations described herein, for example those operations described in Figs. 2 and 3 and the associated text.
- a machine-readable medium may include any mechanism for storing or transmitting information in a form readable by a machine (e.g., a computer).
- a machine-readable medium may include read only memory (ROM); random access memory (RAM); magnetic disk storage media; optical storage media; flash memory devices; electrical, optical, acoustical or other form of propagated signals (e.g., carrier waves, infrared signals, digital signals, etc.), and others.
- Fig. 4 shows a block diagram of a base station, according to an embodiment of the invention.
- Computing platform 450 may include one or more processors, and in some embodiments at least one of the one or more processors may be a digital signal processor (DSP).
- DSP digital signal processor
- AP 110 has four antennas 120, but other embodiments may have two, three, or more than four antennas.
- base station 110 may have a modulator/demodulator 420, an analog- to-digital converter (ADC) 430, and a digital-to-analog converter (DAC) 440.
- ADC analog- to-digital converter
- DAC digital-to-analog converter
- the combination of demodulator- ADC may convert received radio frequency signals from the antenna into digital signals suitable for processing by the computing platform 450.
- the combination of DAC-modulator may convert digital signals from the computing platform 450 into radio frequency signals suitable for transmission through an antenna.
- Other components not shown may be included in the illustrated blocks as needed, such as but not limited to amplifiers, filters, oscillators, etc.
Abstract
Description
Claims
Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US49393703P | 2003-08-08 | 2003-08-08 | |
US10/737,142 US20050144307A1 (en) | 2003-12-15 | 2003-12-15 | Back-end alignment to avoid SDMA ACK time-out |
PCT/US2004/025709 WO2005015848A1 (en) | 2003-08-08 | 2004-08-06 | Back-end alignment to avoid sdma ack time-out |
Publications (1)
Publication Number | Publication Date |
---|---|
EP1661322A1 true EP1661322A1 (en) | 2006-05-31 |
Family
ID=34138785
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP04780531A Withdrawn EP1661322A1 (en) | 2003-08-08 | 2004-08-06 | Back-end alignment to avoid sdma ack time-out |
Country Status (4)
Country | Link |
---|---|
EP (1) | EP1661322A1 (en) |
JP (1) | JP2007502078A (en) |
CN (1) | CN1853373A (en) |
WO (1) | WO2005015848A1 (en) |
Families Citing this family (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20050141420A1 (en) * | 2003-12-24 | 2005-06-30 | Qinghua Li | Transmission coordination for SDMA downlink communication |
JP5485870B2 (en) * | 2007-04-30 | 2014-05-07 | テレフオンアクチーボラゲット エル エム エリクソン(パブル) | Methods and configurations for communication networks |
CN113067664B (en) * | 2019-12-16 | 2022-06-14 | 华为技术有限公司 | Data receiving method, data sending method and related equipment |
Family Cites Families (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP1263168B1 (en) * | 2001-05-29 | 2006-06-28 | Kabushiki Kaisha Toshiba | Wireless communication apparatus |
-
2004
- 2004-08-06 EP EP04780531A patent/EP1661322A1/en not_active Withdrawn
- 2004-08-06 CN CNA2004800265312A patent/CN1853373A/en active Pending
- 2004-08-06 JP JP2006523268A patent/JP2007502078A/en not_active Withdrawn
- 2004-08-06 WO PCT/US2004/025709 patent/WO2005015848A1/en active Application Filing
Non-Patent Citations (1)
Title |
---|
See references of WO2005015848A1 * |
Also Published As
Publication number | Publication date |
---|---|
WO2005015848A1 (en) | 2005-02-17 |
CN1853373A (en) | 2006-10-25 |
JP2007502078A (en) | 2007-02-01 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US20140328167A1 (en) | Response scheduling for multiple receivers | |
US7567612B2 (en) | SDMA communications with non-immediate block acknowledgment | |
EP1661287B1 (en) | Sdma communications with non-immediate block acknowledgment | |
US20050144307A1 (en) | Back-end alignment to avoid SDMA ACK time-out | |
US10819159B2 (en) | Methods of wireless power transfer by energy signal transfer apparatus operating in the same frequency band as wireless local area network in wireless power transfer energy harvesting system and energy signal transfer apparatuses for performing the same | |
US7839836B2 (en) | Arranging SDMA poll groups by response length | |
US20050141420A1 (en) | Transmission coordination for SDMA downlink communication | |
EP1652350A1 (en) | Multicast sdma training polls | |
EP1661321B1 (en) | Variable sdma ack timeout | |
US20050136910A1 (en) | Multicast SDMA training polls | |
US20050111427A1 (en) | SDMA training and operation | |
WO2005015848A1 (en) | Back-end alignment to avoid sdma ack time-out | |
WO2005015847A2 (en) | Sdma training operations |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
PUAI | Public reference made under article 153(3) epc to a published international application that has entered the european phase |
Free format text: ORIGINAL CODE: 0009012 |
|
17P | Request for examination filed |
Effective date: 20060227 |
|
AK | Designated contracting states |
Kind code of ref document: A1 Designated state(s): AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HU IE IT LI LU MC NL PL PT RO SE SI SK TR |
|
17Q | First examination report despatched |
Effective date: 20060921 |
|
DAX | Request for extension of the european patent (deleted) | ||
REG | Reference to a national code |
Ref country code: HK Ref legal event code: DE Ref document number: 1090205 Country of ref document: HK |
|
STAA | Information on the status of an ep patent application or granted ep patent |
Free format text: STATUS: THE APPLICATION IS DEEMED TO BE WITHDRAWN |
|
18D | Application deemed to be withdrawn |
Effective date: 20080304 |
|
REG | Reference to a national code |
Ref country code: HK Ref legal event code: WD Ref document number: 1090205 Country of ref document: HK |