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Publication numberUS20050249183 A1
Publication typeApplication
Application numberUS 11/043,279
Publication dateNov 10, 2005
Filing dateJan 25, 2005
Priority dateJan 8, 2004
Also published asUS7496064, US7936774, US20050237956, US20050237964, US20050237965, US20050238025, US20050238084, WO2005065035A2, WO2005065035A3
Publication number043279, 11043279, US 2005/0249183 A1, US 2005/249183 A1, US 20050249183 A1, US 20050249183A1, US 2005249183 A1, US 2005249183A1, US-A1-20050249183, US-A1-2005249183, US2005/0249183A1, US2005/249183A1, US20050249183 A1, US20050249183A1, US2005249183 A1, US2005249183A1
InventorsTamar Danon, Rafi Zack, Yefim Kupershmidt
Original AssigneeTamar Danon, Rafi Zack, Yefim Kupershmidt
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Method and device for transmission and reception over a distributed media access control network
US 20050249183 A1
Abstract
A method and device for reception and transmission using a distributed media access control scheme. The device includes an interface for receiving a payload including multiple information signals; and circuitry adapted to process the payload to provide an information frame that includes a PHY layer header, multiple payload fragments, multiple fragmentation control fields and multiple payload fragment check sequence fields; and further adapted to transmit the information frame using a distributed media access control scheme; whereas the multiple payload fragments are associated with the multiple fragmentation control fields and with the multiple payload fragment check sequence fields. The method includes: receiving a payload including multiple information signals; processing the payload to provide an information frame that includes a PHY layer header, multiple payload fragments, multiple fragmentation control fields and multiple payload fragment check sequence fields; and transmitting the information frame using a distributed media access control scheme; whereas the multiple payload fragments are associated with the multiple fragmentation control fields and with the multiple payload fragment check sequence fields.
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Claims(21)
1. A method for transmission over a network, the method comprises:
receiving at least multiple information signals;
processing the multiple information signals to provide an information frame that comprises a PHY layer header, multiple payload fragments, multiple fragmentation control fields and multiple payload fragment check sequence fields; and
transmitting the information frame while utilizing a distributed media access control scheme;
whereas the multiple payload fragments are associated with the multiple fragmentation control fields and with the multiple payload fragment check sequence fields.
2. The method of claim 1 whereas each payload fragment is associated with a fragmentation control field and with a payload fragment check sequence field.
3. The method of claim 1 whereas a payload fragment is substantially smaller than the payload.
4. The method of claim 1 whereas the stage of processing further comprises providing a MAC layer header that includes fragmentation information representative of a structure of the information frame.
5. The method of claim 1 whereas most payload fragments are of the same length.
6. The method of claim 1 whereas the payload further comprises an aggregate header.
7. The method of claim 1 wherein the network is a ultra wide band access network.
8. A device, comprising:
an interface for receiving at least multiple information signals ; and
circuitry adapted to process the at least multiple information signals to provide an information frame that comprises a PHY layer header, multiple payload fragments, multiple fragmentation control fields and multiple payload fragment check sequence fields; whereas the multiple payload fragments are associated with the multiple fragmentation control fields and with the multiple payload fragment check sequence fields; and
whereas the circuitry is further adapted to transmit the information frame using a distributed media access control scheme.
9. The device of claim 8 whereas the transmission occurs over an ultra wide band wireless medium.
10. The device of claim 8 whereas each payload fragment is associated with a fragmentation control field and with a payload fragment check sequence field.
11. The device of claim 8 whereas a payload fragment is substantially smaller than the payload.
12. The device of claim 8 whereas the circuitry is adapted to provide a MAC layer header that includes fragmentation information representative of a structure of the information frame.
13. The device of claim 8 whereas the payload further comprises an aggregate header.
14. A method for reception, the method comprises:
receiving an information frame that was transmitted utilizing a distributed media access control scheme, the information frame comprises a PHY layer header, multiple payload fragments, multiple fragmentation control fields and multiple payload fragment check sequence fields; whereas the multiple payload fragments are associated with the multiple fragmentation control fields and with the multiple payload fragment check sequence fields; and
processing the information frame to provide a payload that comprises multiple information signals.
15. The method of claim 14 whereas each payload fragment is associated with a fragmentation control field and with a payload fragment check sequence field.
16. The method of claim 14 whereas a payload fragment is substantially smaller than the payload.
17. The method of claim 14 whereas the payload further comprises an aggregate header.
18. A device, comprising:
a receiver interface adapted to receive an information frame that was transmitted using a distributed media access control scheme, the information frame includes a PHY layer header, multiple payload fragments, multiple fragmentation control fields and multiple payload fragment check sequence fields; whereas the multiple payload fragments are associated with the multiple fragmentation control fields and with the multiple payload fragment check sequence fields; and
circuitry adapted to process the information frame to provide a payload that comprises multiple information signals.
19. The device of claim 18 whereas each payload fragment is associated with a fragmentation control field and with a payload fragment check sequence field.
20. The device of claim 18 whereas a payload fragment is substantially smaller than the payload.
21. The device of claim 18 whereas the payload further comprises an aggregate header.
Description
RELATED APPLICATIONS

The present patent application is a continuation application of International Application No. PCT/IL05/000021 filed Jan. 6, 2005, which claims priority benefit from United States Provisional Application No. 60/535,436 filed Jan. 8, 2004 and United States Provisional Application No. 60/535,621 filed Jan. 8, 2004, the contents of which are incorporated herein by reference.

This application is related to the following applications:

  • 1. METHOD AND DEVICES FOR MULTICASTING INFORMATION OVER A NETWORK THAT APPLIED A DISTRIBUTED MEDIA ACCESS CONTROL SCHEME, application Ser. No. ______, filed Jan. 25, 2005.
  • 2. METHODS AND DEVICES FOR EXPANDING THE RANGE OF A NETWORK, application Ser. No. ______, filed Jan. 25, 2005.
  • 3. METHOD AND SYSTEM FOR OPERATING MULTIPLE DEPENDENT NETWORKS, application Ser. No. ______, filed Jan. 25, 2005.
  • 4. A DEVICE AND METHOD FOR MAPPING INFORMATION STREAMS To MaC LAYER QUEUES, application Ser. No. ______, filed Jan. 25, 2005.
  • 5. ULTRA WIDE BAND WIRELESS MEDIUM ACCESS CONTROL METHOD AND A DEVICE FOR APPLYING AN ULTRA WIDE BAND WIRELESS MEDIUM ACCESS CONTROL SCHEME, application Ser. No. ______, filed Jan. 25, 2005.

1. Field of the Invention

The invention relates to method and devices for transmission and reception over distributed media access control networks and especially over ultra wide band wireless networks utilizing a distributed media access control scheme.

2. Background of the Invention

Recent developments in telecommunication and semiconductor technologies facilitate the transfer of growing amounts of information over wireless networks.

Short-range ultra wide band wireless networks are being developed in order to allow wireless transmission of vast amounts of information between various devices.

Some of the short-range ultra wide band wireless networks are characterized by a distributed architecture in which devices exchange information without being controlled by a central host or a base station.

FIG. 1 is a schematic illustration of two ultra wide band wireless networks (also referred to as personal access networks) 10 and 20, each including multiple devices that wirelessly communicate with each other. First network 10 includes first till third devices A-C 11-13 and the second network 20 includes forth till sixth devices D-F 24-26.

Each of the ultra wide band wireless networks uses time division multiple access (TDMA) techniques in order to allow its devices to share a single channel.

FIG. 2 illustrates a typical TDMA frame 30. TDMA frame 30 includes multiple time-slots, such as beacon slots 14 and media access slots. The media access slots include distributed reservation period (DPR) slots 36 and prioritized contention access (PCA) slots 38. PCA slots are also referred to as PCA periods. DRP slots are also referred to as DRP periods.

The beacon slots are used to synchronize devices to the TDMA frame 30. A typical beacon frame includes information that identifies the transmitting device. It also may include timing information representative of the start time of the TDMA frame 30.

The DRP slots 36 are coordinated between devices that belong to the same network and allow devices to reserve these slots in advance. During the PCA slots 38 devices that belong to the network compete for access based upon their transmission priority. It is noted that the allocation of media access time slots is dynamic and can change from one TDMA frame to another.

Typically, transmissions from devices during PCA slots are assigned by applying a carrier sense multiple access with collision avoidance (CSMA/CA) scheme If a device requests to transmit over a wireless medium it has to check if the wireless medium is idle. If the wireless medium is idle, the device has to wait a random backoff period. This random backoff time is selected from a contention window that has a length that is related to the priority of the device. For higher-priority devices the contention window is shorter.

The transmission process is usually quite complex and includes many operations such as but not limited to forward correction encoding, interleaving, modulating and the like. A receiver must reverse the procedures applied by the transmitter.

Various techniques are applied in order to increase the reliability of wireless telecommunications. A first technique includes sending acknowledgement messages to indicate a reception of a certain information frame when performing point-to-point transmission. These acknowledgement messages can be sent per frame (Immediate ACK scheme) or per a group of frames (Burst ACK scheme). The former decreases the communication channel utilization but reduces communication error penalty. Burst ACK scheme is capable of keeping high throughput at the price of higher implementation complexity and higher memory requirements for a device. The acknowledgement transmission techniques (Imm-ACK and B-ACK) are not applied when performing multicast or broadcast transmission over ultra wide band wireless networks.

In some networks that include a central station and various clients or a master station and multiple slave stations various acknowledgment schemes were applied. The following U.S. patent, U.S. patent applications and PCT patent application, all being incorporated herein by reference, provide an example of some prior art methods and systems: U.S. patent application 2001/0051529 of Davies titled “Radio system and apparatus for, and method of, multicast communication”; U.S. Pat. No. 6,122,483 of Lo et al. titled “Method and apparatus for multicast messaging in a public satellite network”; U.S. patent application 2003/0145102 of Keller-Tuberg, titled “Facilitating improved reliability of internet group management protocol through the use of acknowledgment massages”; and PCT patent application WO2004/084488 of Lynch et al, titled “Method and apparatus for reliable multicast”.

Another technique involves introducing forward error correction encoding, such as convolutional encoding, that puts redundancies in the information that can be used to correct a limited amount of errors. Yet a further technique included only error detection, and not correction.

It is noted that in some applications (such as but not limited to streaming video, sound, and the like) the performance and the user experience deteriorate significantly when the non-acknowledgement schemes are used with nominal channel conditions (˜1-8% Packet Error Ratio). Also, using acknowledge schemes in layers above the MAC layer (such as TCP/IP layers) increase significantly the latency and memory requirements and in some cases make the application impractical if not impossible from implementation standpoint.

There is a need to increase the reliability of ultra wide band transmission while keeping the throughput high and implementation requirements overhead low, reducing transmission or reception error penalty.

SUMMARY OF THE INVENTION

A device for transmission. The device includes: (i) an interface for receiving at least multiple information signals; and (ii) circuitry adapted to process the at least multiple information signals to provide an information frame that includes a PHY layer header, multiple payload fragments, multiple fragmentation control fields and multiple payload fragment check sequence fields. The circuitry is further adapted to transmit the information frame over a network that utilized a distributed media access control scheme. The multiple payload fragments are associated with the multiple fragmentation control fields and with the multiple payload fragment check sequence fields.

A method for transmission includes: (i) receiving at least multiple information signals; (ii) processing the at least information signals to provide an information frame that includes a PHY layer header, multiple payload fragments, multiple fragmentation control fields and multiple payload fragment check sequence fields; and (iii) transmitting the information frame over a network that utilizes a distributed media access control scheme; whereas the multiple payload fragments are associated with the multiple fragmentation control fields and with the multiple payload fragment check sequence fields.

A method for reception, the method includes: (i) receiving, an information frame that was transmitted over a network that utilizes a distributed media access control scheme, the information frame includes a PHY layer header, multiple payload fragments, multiple fragmentation control fields and multiple payload fragment check sequence fields; whereas the multiple payload fragments are associated with the multiple fragmentation control fields and with the multiple payload fragment check sequence fields; and (ii) processing the information frame to provide a payload that comprises multiple information signals.

DESCRIPTION OF THE DRAWINGS

The present invention will be understood and appreciated more fully from the following detailed description taken in conjunction with the drawings in which:

FIG. 1 is a schematic illustration of two networks (also referred to as personal access networks), each including multiple devices that wirelessly communicate with each other;

FIG. 2 illustrates a typical TDMA frame;

FIG. 3 illustrates a proposed MBOA information frame;

FIGS. 4 a-4 b illustrate a device capable of wireless transmission, and some of its components, according to an embodiment of the invention;.

FIGS. 5 and 9 illustrate an information frame, according to an embodiment of the invention;

FIG. 6 illustrates the throughput achieved when using different information frames;

FIG. 7 is a flow chart that illustrates a method for transmission, according to an embodiment of the invention; and

FIG. 8 is a flow chart that illustrates a method for reception, according to an embodiment of the invention.

DETAILED DESCRIPTION OF THE DRAWINGS

The following description related to wireless ultra wide band networks that utilize a distributed media access control scheme. In these networks there is no central media access controller, but rather various devices of the network participate in determining how to share a common wireless medium. It is noted that according to various embodiments of the invention the disclosed methods and devices can be applied in networks that utilize a distributed media access control scheme but differ from ultra wide band wireless networks.

Various operations such as transmissions utilize the distributed media access control scheme in the sense that the access to a shared medium is governed by a distributed media access control scheme.

MBOA is a standard that is being developed by various vendors in the field of ultra wide band wireless communication. A MBOA transmitter has a PHY layer that is capable of performing multiple operations, such as but not limited to convolutional encoding, bit padding, time frequency code (TFC) interleaving, Quadrature Phase Shift Key (QPSK) modulation and Orthogonal Frequency Division Multiplexing (OFDM).

A typical transmitter includes a convolutional encoder, an interleaver and a OFDM modulator. An information sequence enters a convolutional encoder that adds redundant bits, the sequence is then interleaved in order to cope with burst errors, and then OFDM modulated. Said modulation includes mapping multiple signals to multiple narrowband subcarriers and performing inverse Fourier transform to provide a sequence of OFDM symbols.

FIG. 3 illustrates a proposed MBOA information frame 100. The information frame 100 includes a physical layer convergence procedure (PLCP) preamble 112, a PHY layer header 114, a MAC layer header 116, a header check sequence field (HCS) 118, header tail bits 120, header pad bits 121, payload 122, a frame check sequence field (FCS) 124, frame tail bits 126 and pad bits 128.

The information frame 100 includes MAC layer fields such as fields 116, 118, 122 and 124. Information frame 100 also includes various PHY layer fields, such as fields 112, 114, 120, 121, 126 and 128. The payload 122 usually includes one or more MAC layer frames (also known as MSDU or MCDU) or frames of a upper communication protocol layer, such as an application layer. Typically information frame 100 includes a single upper layer frame.

The PLCP preamble 112 includes a packet and frame synchronization sequences that are followed by a channel estimation sequence. The PLCP preamble assists the receiver, among other things, to estimate the properties of the wireless medium. MBOA proposes two possible PLCP preambles—a short PLCP preamble and a long PLCP preamble. The long PLCP preamble is used at low bit rates. At high bit rates a first frame includes the long PLCP preamble while the remaining frames include the short PLCP preamble.

The PHY layer header 114 includes information about the type of modulation, the coding rate and the spreading factor used during the transmission of the information, the length of the frame payload and scrambling data information.

MAC layer header 116 includes a frame control field, source and destination identification fields, sequence control fields 117 and duration/access method fields.

The header tail bits 120 as well as the frame tail bits 126 are set to zero, thus allowing a convolutional encoder within the receiver to return to a “zero state” and improve its error probability. The header tail bits 120 (the frame tail bits 126) are followed by header pad bits 121 (frame pad bits 128) in order to align the information stream on an OFDM interleaver boundaries.

The payload is usually between one byte and 4096 bytes long. When a transmission or reception error occurs the whole frame is re-transmitted.

The mentioned below information frame is transmitted by a device that is a part of a wideband wireless network and has a communication protocol stack that includes at least a PHY layer and a MAC layer. The MAC layer of such devices controls the access to ultra wide band wireless medium and is referred to ultra wide band wireless medium access control.

Examples of devices that have a PHY layer are illustrated in the following U.S. patent applications, all being incorporated herein by reference: U.S. patent application Ser. No. 10/389789 filed on Mar. 10, 2003 and U.S. patent application Ser. No. 10/603,372 filed on Jun. 25 2003.

The device can include various components that are arranged in multiple layers. A first configuration includes a frame convergence sub-layer, a MAC layer, a PHY layer as well as MAC SAP, PHY SAP, frame convergence sub-layer SAP and a device management entity can also be utilized. Another configuration is described at FIGS. 4 a and 4 b.

Wisair Inc. of Tel Aviv Israel manufactures a chip set that includes a Radio Frequency PHY layer chip and a Base-Band PHY layer chip. These chips can be connected in one end to a RF antenna and on the other hand be connected or may include a MAC layer circuitry.

FIG. 4 a illustrates a device 60 that is capable of wireless transmission, according to an embodiment of the invention.

Device 60 includes antenna 61 that is connected to a RF chip 62. RF chip 62 is connected to a MAC/PHY layers chip 63 that includes a PHY layer block 63 and a MAC layer block 64. The MAC/PHY layers chip 63 is connected to an application entity 66 that provides it with information to be eventually transmitted (TX) and also provides the application 66 with information received (RX) by antenna 61 and processed by PHY and MAC layers blocks 68 and 69 of FIG. 4 b.

Typically, the MAC layer block 64 controls the PHY layer block using a PHY status and control interface. The MAC and PHY layers exchange information (denoted TX and RX) using PHY-MAC interface 90. The RF chip 62 provides to the PHY layer block 63 received information that is conveniently down-converted to base band frequency. The RF chip 62 receives from the PHY layer block 63 information to be transmitted as well as RF control signals. The application 66 is connected to the MAC/PHY layers chip 63 by a high speed I/O interface.

FIG. 4 b illustrates various hardware and software components of the MAC/PHY layers chip 63, according to an embodiment of the invention.

The Upper Layer IF block 64 of the MAC/PHY layers chip 63 includes hardware components (collectively denoted 69) and software components (collectively denoted 68). These components includes interfaces to the PHY layer (MAC- PHY interface 90) and to the application (or higher layer components).

The hardware components 69 includes configuration and status registers 81, Direct Memory Access controller and list processor 82, First In First Out (FIFO) stacks 83 and frame validation and filtering components 84, DRP and PCA slots schedulers 85, ACK processors 86, and MAC-PHY internal interface 87.

The software components 68 includes a management module 72, transmit module 73, receive module 74 m hardware adaptation layer 75, DMA drivers 76, MAC layer management entity (MLME) service access point (SAP) 71, MACS API 70 and the like.

These software and hardware components are capable of performing various operations and provide various services such as: providing an interface to various layers, filtering and routing of specific application packets sent to MAC data queues or provided by these queues, performing information and/or frame processing, and the like.

The routing can be responsive to various parameters such as the destinations of the packets, the Quality of Service characteristics associated with the packets, and the like.

The processing of information along a transmission path may include: forming the MAC packet itself, including MAC header formation, aggregation of packets into a bigger PHY PDU for better efficiency, fragmentation of packets for better error rate performance, PHY rate adaptation, implementation of Acknowledgements policies, and the like.

The processing of information along a reception path may include de-aggregation and/or de-fragmentation of incoming packets, implementation of acknowledgment and the like.

The hardware components are capable of transferring data between MAC software queues and MAC hardware (both TX and RX), scheduling of beacons slots, scheduling of DRP and PCA access slots, validation and filtering (according to destination address of incoming frames, encryption/decryption operations, low-level acknowledgement processing (both in the TX path and in the RX path).

Device 60 can be a simple device or even a complex device such as but not limited to a multimedia server that is adapted to transmit information frames of different types to multiple devices. It can, for example transmit Streaming data, like voice, Video, Game applications, etc.) data files during DRP slots, and while PCA slots transmits video over IP frames download MP3 files, download MPEG-2 files, and stream or download MPEG-4 streams.

It is noted that device 60 is capable of receiving as well as transmitting information. Thus device 60 includes a receiver that includes multiple software and hardware components that are capable of substantially reversing the operation of the device transmitter portions.

The receiver includes a receiver interface (such as antenna and RF chip) adapted to receive an information frame that was transmitted over an ultra wide band wireless medium, the information frame includes a PHY layer header, multiple payload fragments, multiple fragmentation control fields and multiple payload fragment check sequence fields; whereas the multiple payload fragments are associated with the multiple fragmentation control fields and with the multiple payload fragment check sequence fields. That receiver also includes circuitry (such as MAC layer components) for processing the information frame to provide a payload that comprises multiple information signals.

FIG. 5 illustrates information frame 200, according to an embodiment of the invention.

The information frame 200 includes a PHY layer preamble, such as PLCP preamble 112, a PHY layer header 114, a modified MAC layer header 116′, HCS 118, header tail bits 120, header pad bits 121. These are followed by a sequence 210 of fragmentation control fields 212(1)-212(K), payload fragments 214(1)-214(K) and payload fragment check sequence field 216(1)-216(K). Whereas K is a positive integer representing the amount of payload fragments per information frame 200 and whereas each payload fragment is preceded by a corresponding fragmentation control field and is followed by a payload fragment check sequence field. Sequence 210 is followed by a frame check sequence field (FCS) 124, frame tail bits 126 and pad bits 128.

Most of the fragments, except the last fragment have the same size, thus information about their size is not transmitted. This is not necessarily so.

It is noted that the size of the fragment can be pre-negotiated or otherwise defined and transmitted to the receiver. Alternatively, part MAC header, like the Sequence Control field of the MAC header can be used to notify the size of the fragment in a particular aggregated frame.

It is noted that the information frame can include a long PLCP preamble, or a short PCLP preamble, according, for example to the bit rate and the order of an information frame within a series of information frames.

The inventors found that by using relatively short payload fragments and associating a payload fragment check sequence field and a fragmentation control field the penalty of errors is dramatically reduced from the size of a PHY frame to the size of a payload fragment.

FIG. 6 illustrates the throughput achieved when using different information frames.

The X-axis represents the PHY layer data rate. The Y-axis represents the effective throughput at Million bits per second. The effective throughput is the rate of information payload.

The following curves were generated by simulating a transmission sequence of a first information frame that includes a long PCLP preamble, followed by five information frames that include a short PCLP preamble.

It is noted that these graphs were simulated under the assumption that no re-transmissions are required. It is noted that the low overhead associated with this scheme increases throughput.

Curve 82 illustrates the transmission of information frame such as information frame 200, while the other curves illustrate the transmission information frames such as information frame 100, of various lengths.

The upper curve 81 represents the effective throughput achieved when using information frames of four thousand bits. At a PHY data rate of about four hundred and eighty Mbps an effective throughput of four hundred Mbps was achieved.

The following curve 82 represents the effective throughput achieved when using information frames of about four thousand bits that include multiple two hundred and fifty six bit fragments. At a PHY data rate of about four hundred and eighty Mbps an effective throughput of three hundred and ninety Mbps was achieved.

The four lower curves 83-86 represent the effective throughputs achieved when using information frames of two thousand, one thousand, five hundred and two hundred and fifty bits, accordingly. At a PHY data rate of about four hundred and eighty Mbps effective throughputs of three hundred and fifty, two hundred and eighty, one hundred and ninety and one hundred and ten Mbps respectively was achieved.

FIG. 7 illustrates a method 300 for transmission, according to an embodiment of the invention.

Method 300 starts by stage 310 of receiving at least multiple information signals. According to an embodiment of the invention the information signals can belong to multiple frames.

Stage 310 is followed by stage 320 of processing the at least multiple information signals to provide an information frame that includes a PHY layer header, multiple payload fragments, multiple fragmentation control fields and multiple payload fragment check sequence fields. Conveniently, the multiple payload fragments are associated with the multiple fragmentation control fields and with the multiple payload fragment check sequence fields. It is noted stage 310 does not necessarily include processing all the received signals. It is also noted that during said processing some signals can be modified, other signals can be deleted and the like.

According to an embodiment of the invention stage 310 includes aggregating signals from multiple payloads and/or frames. Conveniently, the control bits associated with each received frame can be modified or remain unchanged. The control bits may include MAC header bits and the like.

Conveniently, after the fragments and other parts of the information frame are generated the processing continues to aggregate them into an information frame. Said aggregation can also require an alteration of the information frame header, for example for notifying that the information frame is an aggregated frame.

Conveniently, each payload fragments is associated with a fragmentation control field and with a payload fragment check sequence field.

Conveniently, a payload fragment is substantially smaller than the payload.

According to an embodiment of the invention stage 320 further includes providing a MAC layer header that includes fragmentation information representative of a structure of the information frame.

Conveniently, at least most payload fragments are of the same length. Typically, the last fragment sizes differs from the size of other fragments.

Conveniently, the fragmentation control fields include a payload sequence serial number and also include a fragment serial number.

Stage 320 is followed by stage 330 of transmitting the information frame utilizing a distributed media access control scheme. This stage can involve transmitting over a ultra wide band wireless medium.

FIG. 8 illustrates a method 400 for reception, according to an embodiment of the invention.

Conveniently, a receiver that executes the stages of method 400 substantially reverses the stages applied by a transmitted applying method 300.

Method 400 starts by stage 410 of receiving an information frame that was transmitted over a network that applied a distributed media access control scheme. The transmission can involve a transmission over an ultra wide band wireless medium. The information frame includes a PHY layer header, a MAC header with notification of the type of frame (In-MPDU fragmented), multiple payload fragments, multiple fragmentation control fields and multiple payload fragment check sequence fields; whereas the multiple payload fragments are associated with the multiple fragmentation control fields and with the multiple payload fragment check sequence fields.

Stage 410 is followed by stage 420 of processing the information frame to provide a payload that includes multiple information signals.

According to various embodiments of the invention the device is capable of aggregating multiple MAC layer frames to a single PHY frame. These MAC layer frames or MAC layer segments can be treated as information frame 500 fragments.

FIG. 9 illustrates an information frame 500 that includes a PHY layer preamble, such as PLCP preamble 112, a PHY layer header 114, a modified MAC layer header 116″, HCS 118, header tail bits 120, header pad bits 121. These are followed by an aggregation header 502, and a sequence 510 of fragmentation control (FC) fields 512(1)-512(K), payload fragments 514(1)-514(K) and payload fragment check sequence (FCS) fields 516(1)-516(K). The FC fields can also indicate if a certain payload fragment is the last within the PHY frame. The last FCS field 516(K) is followed by a frame check sequence field (FCS) 124, frame tail bits 126 and pad bits 128.

The aggregation header 502 includes the following fields: amount of MAC layer frames 522, and for each payload fragment its length 524(1)-524(K), and a fragmentation control fields 526(1)-526(K) indicating whether this is a fragment of a MAC layer frame and if so whet is it's serial number. It is noted that at least some of the payload fragments can be MAC layer frames. In such a case the MAC layer frames are not necessarily fragmented in order to generate the information frame 500.

It is assumed that the information frame 500 is generated in response to a reception of one or more original frames. According to various embodiments of the invention the information frame can be generated in various manners. The information frame can include the payloads of more than one original frame but can also include portions of a single original frame. For example, the information frame can be generated by aggregating original frames that include their own frame check sequence protection fields. Yet for another example, the information frames can be generated by fragmenting a single original frame and adding various fields.

According to another embodiment of the invention the information frame 500 does not include FCS or FC fields for each payload fragment, and the aggregation header is altered accordingly.

According to various embodiments of the invention the device can dynamically determines the configuration of a transmitted information frame in response to wireless medium quality and in response to a quality of service associated with certain applications. The wireless medium quality can be assessed by monitoring transmission successes and failures (for example monitoring acknowledge based transmissions), by performing an PHY layer SNR estimation, and the like. The quality of service can be represented by various parameters including, for example, packet error rate, latency, interval between channel reservation, and the like.

It will be apparent to those skilled in the art that the disclosed subject matter may be modified in numerous ways and may assume many embodiments other then the preferred form specifically set out and described above.

Accordingly, the above disclosed subject matter is to be considered illustrative and not restrictive, and to the maximum extent allowed by law, it is intended by the appended claims to cover all such modifications and other embodiments, which fall within the true spirit and scope of the present invention.

The scope of the invention is to be determined by the broadest permissible interpretation of the following claims and their equivalents rather then the foregoing detailed description.

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Classifications
U.S. Classification370/347, 370/473
International ClassificationH04B1/713, H04B7/212, H04B7/26, H04B7/00, H04B1/707, H04B1/69, H04L12/28, H04L12/56
Cooperative ClassificationH04B1/7163, H04W28/14, H04B2201/70702, H04W72/1263, H04B7/2628, H04L45/16, H04W88/04, H04W72/0446, H04W28/065, H04L47/14, H04L45/00, H04W72/1242, H04W74/08
European ClassificationH04B7/26S, H04W88/04, H04W72/12D, H04W72/12B6, H04W72/04H2, H04L45/00, H04L45/16, H04L47/14, H04W28/06D
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