JP2003534745A - Frame header of data communication channel - Google Patents

Abstract

(57) [Summary] A data channel for transmitting data from a base station to a subscriber station is provided. Each subscriber station has a different class of service that reflects the ability to receive data transmitted from the base station. The data channel is organized into a plurality of frames. Each frame contains class of service information, which is packaged in a frame so that all subscriber stations can recover the class of service information. The frame also includes payload data designated as at least one subscriber station. The payload data is packaged in frames such that the payload data can be restored by the designated subscriber station regardless of its class of service. Subscriber stations with no payload data specified and a lower grade of service than the designated subscriber station use the class of service information to determine that the rest of the frame can be ignored. Apparatus, systems and methods for a data channel are also provided.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD OF THE INVENTION

The present invention relates generally to methods and systems for transmitting data from base stations to subscriber stations. More particularly, it relates to a method and system for transmitting data from a base station to subscriber stations that differ in their ability to receive a transmitted signal, thereby packaging the transmitted signal.

[0002]

[Prior art]

Wireless communication is very advanced and growing. CDMA, FDMA or TDM
Current digital wireless telephone networks based on multiple access technologies such as A can provide high quality voice communications. However, such a network is inefficient in providing data communication to a large number of users, and a demand for data communication via a wireless network is expected to increase rapidly.

For example, the IS-95 standard for CDMA networks can provide a maximum data rate of 9.6 kbaud or 14.4 kbaud depending on the service selected. However, as will be apparent to those skilled in the art, such speeds are generally too slow to accommodate modern data applications, such as web browsing and / or file transfer. Within IS-95, attempts are being made to increase the maximum data rate. For example, Od
Enwalder US Pat. No. 5,930,230 discloses a high data rate CDMA wireless communication system with some improvements over IS-95. However, Oenderwalder focuses on the CDMA environment and deals primarily with data transfer from the subscriber station to the base station (usually referred to as the "uplink" or "reverse" channel), and the base station joins. It does not address the need for increased data transmission to the central office (usually referred to as the "downlink" or "forward" channel).

In the IS-95 type network, since a dedicated communication channel is allocated between the base station and the subscriber unit, when there is no data transmitted between the base station and the subscriber unit. However, there is another problem that the bandwidth of the dedicated channel cannot be used by other users in the network. Thus, in connectionless services such as packet networks, such systems typically do not provide the efficient use of the limited bandwidth required to service a large number of users.

US Pat. No. 5,949,814 (Od, also issued to Odenwalder
enhancer # 2) teaches a system for providing high data rate additional channels in a CDMA telecommunications system. In such a configuration, the transmission system includes an in-phase channel set and a quadrature-phase channel set. The in-phase component channel set provides a set of orthogonal intermediate rate control and traffic channels, and the quadrature component channel set provides a high rate supplemental channel and an extended set of intermediate rate channels orthogonal to each other.

Although the downlink data transmission rate can be increased in Odenwalder # 2, it is generally not suitable for data transmission to a large number of subscriber stations having different ability to receive a transmission signal. Further, the Oenderwalder # 2 starts a high data rate communication between the base station and the mobile user, and thus requires a certain overhead control communication between the base station and the mobile user. Such systems are not suitable for systems such as packet communication systems where small amounts of data need to be transmitted, because of the amount of data transferred due to the overhead required by such communications. This is because it becomes inefficient. Similarly, such systems are not suitable in situations where diverse users require the data to be transmitted to them.

[0007]

[Problems to be Solved by the Invention]

It is an object of the present invention to provide a novel method, system and apparatus for transmitting data from a base station to one or more subscriber stations so that at least some of the above mentioned problems of the prior art can be eliminated or alleviated. To provide.

[0008]

[Means for Solving the Problems]

According to one aspect of the invention, a base station comprising a microprocessor, a modem, a radio device and an antenna for transmitting radio signals, a microprocessor, a modem,
A plurality of subscriber stations comprising a wireless device and an antenna, the subscriber stations receiving the signal with different reception capabilities and at least one other subscriber station, the signals being independent of the reception capabilities of all the subscribers. A station-restorable identifier and a frame having a remaining portion that the at least one subscriber station can restore, the identifier indicating whether the subscriber station needs to restore the remaining portion. A data transmission system is provided that is indicative of

According to another aspect of the present invention, a frame transmitted to a plurality of subscriber stations having a receiving capability corresponding to the capability of restoring a frame, the frame being restored regardless of the receiving capability. An identifier that includes information indicating whether the subscriber station is within the range of reception capability, and address information that is packaged to be restored by the subscriber station within the range. Is provided and a frame is included that includes at least one payload packet that is packaged for restoration by the at least one subscriber station indicated by the address information.

A data channel is provided for transmitting data from the base station to the subscriber stations.
Each subscriber station has a different class of service that reflects the ability to receive data transmitted from the base station. The data channel is organized into frames. Each frame contains grade of service information, which is packaged in the frame so that all subscriber stations can restore it. The frame also includes payload data specified for at least one subscriber station. The payload data is packaged in a frame so that the subscriber station to which the payload data is designated can recover the payload data regardless of the class of service. A subscriber station with no payload data specified and a lower service class than the specified subscriber station determines that it can ignore the rest of the frame using the service class information. Further provided are devices, systems and methods relating to data channels.

[0011]

DETAILED DESCRIPTION OF THE INVENTION

Referring to FIG. 1, a wireless network incorporating a data transmission system is indicated generally by the reference numeral 20. The network 20 includes a wireless base station 24 and a plurality of subscriber stations 28a, 28b ,. ． ． , 28n. Currently in the preferred embodiment,
The radio base station 24 has an appropriate gateway and one or more backhauls (return relay).
(Not shown in FIG. 1) is connected to a data telecommunications network (not shown), such as a landline based data switching network. The backhaul is T1,
T3, E1, E3, OC3 or any other suitable landline link, satellite or other radio or microwave channel link, or any other link suitable for use as a backhaul by those skilled in the art. Can be.

Base station 24, as is common in wireless subscriber line (WLL) systems,
In the present embodiment, the "n" subscriber stations communicate with subscriber stations 28 that are fixedly attached to the subscriber premises, and the "n" subscriber stations are the amount of available radio bandwidth and / or of the subscriber stations 28. It can vary depending on the configuration and requirements.

A data channel 32 is established between the base station 24 and each subscriber station 28. The data channel 32 is provided from the base station 24 to the respective subscriber stations 28a, 28b ,. ． ． , 28n. The data channel 32 can be implemented in a network using a variety of connection technologies including hybrid systems such as TDMA, FDMA, CDMA or GSM. In this embodiment, the data transmitted through the data channel 32 is transmitted as packets encapsulated in a frame, which will be described in detail later.

The ability of the base station 24 to correctly receive a signal transmitted to the base station 24 (hereinafter, referred to as “reception-quality” of a signal) is
It is determined differently depending on the multiple access technology used for the signal transmission. For example, in TDMA or FDMA systems, received signal strength is the most commonly used determinant. In CDMA systems, the ratio of the received bit power versus received noise power (often expressed as E _s / N _o, where, E _s is per symbol power, N _o is the received noise power) is associated Is a determinant factor. In any case, the receiving capacity of the data channel 32 at each subscriber station 28 depends on multipath interference (due to the presence of nearby buildings, etc.), radio noise sources (including transmitted signals by other users or radio noise sources), geography. Characteristics, the distance between the subscriber station 28 and the base station 24, the quality of the receiver of the subscriber station 28, and the like.
This will be well understood by those skilled in the art. With distance, the signal typically attenuates as 1 / r ^N , where r is the distance between subscriber station 28 and base station 24, where N> 1. In the IS-95 CDMA system, for example, N
Is usually 3 <N <5.

In FIG. 1, the receiving capabilities experienced by a subscriber station are organized and represented as ring 36, where each ring 36a, 36b ,. ． ． , 36n includes respective subscriber stations 28a, 28b ,. ． ． , 28n. In the figure, the rings 36a, 36b ,. ． ． , 36n are shown to extend concentrically to represent increasing distances about the base station 24, but in practice
The ring 36 is defined by the reception capability at the subscriber station 28, and thus the subscriber station 28b is physically located closer to the base station 24 than the subscriber station 28a, but may affect reception capabilities such as near noise sources. Due to the above-mentioned factors that cause the same, they exist in the same ring 36b (reception capability is worse than the ring 36a). Therefore, as will be appreciated by those skilled in the art, FIG. 1 is a logical representation of the receive capability ring 36.

Also shown in FIG. 1 is one subscriber station 28 a, 28 n ,. ． ．
, 28n only, but in the most practical implementation of the invention, each ring 36 includes a large number of subscriber stations 28 having receiving capabilities within the receiving capabilities defined for that ring. Please understand that it will be done. For example, the ring 36a includes a subscriber station 28 having a reception capability of more than 20db, the ring 36b includes a subscriber station 28 having a reception capability of 10db to 20db, and the ring 36n has a reception capability of -20db to 0db. A subscriber station 28 may be included. Therefore, the ring 36 between the ring 36b and the ring 36n has a receiving capability of 0 db to 10 db. In either case, as shown in FIG.
The subscriber station 28b receives data through the data channel 32 having a reception capability lower than that of b.
The data is received through the data channel 32, which has a poorer receiving capability than the subscriber station 28a but a better receiving capability than the subscriber station 28n. As will be described later in detail, the data to be transmitted to the base station 28 is packaged and transmitted according to the ring 36 to which it currently belongs.

In the most practical embodiment, each subscriber station 28 differs due to factors such as weather and / or local noise generated from other electrical devices located near that subscriber station 28. It may change to different rings 36 over time. Thus, at appropriate intervals or scheduled events, each subscriber station 28 reports to the base station 24 their current reception capabilities. The base stations 24 are operated to maintain an up-to-date database of receiving capabilities and also group the subscriber stations 28 into rings 36 according to the range of receiving capabilities defined for each ring 36.

As used in the present invention, “package”, “packaged”, “packaged” (package).
The term ng) refers to the overall arrangement for transmitting packaged data for reception at a specified destination. Different levels of forward error correction (FEC) are used to package the data.
action code (from non-coding to high level coding and / or different coding methods), different transmission rates, different modulation schemes (QPSK, QAM4, QAM16, QAM64, etc.) and required radio (Or other physical layer) includes, but is not limited to, other techniques or methods for arranging data transmission by selecting the amount of resources, data rate and transmission error probability adapted to the transmission. For example, a data packet is 1/4
Coding and QAM64 modulation are packaged and transmitted to the designated first receiver, other packets are packaged with 1/2 coding and QAM256 modulation, and the receiving capability is better designated than the first receiver. Can be transmitted to a second receiver.

FIG. 2 shows the base station 24 in more detail. The base station 24 uses the communication channel 3
2 includes one antenna 40 or a plurality of antennas for receiving and transmitting wireless communication signals. The antenna 40 is connected to the wireless device 44 and the modem 48. The modem 48 is connected to the microprocessor router assembly 52. A suitable microprocessor is the SPARC processor system manufactured by SUN Microsystems. Assembly 52 can include multiple microprocessors if desired. The router in the microprocessor router assembly 52 is connected to a backhaul 56 which connects the base station 24 to a packet data switching network (PSDN) (not shown) in a compatible manner.

Referring to FIG. 3, subscriber station 28 is shown in greater detail. Subscriber station 28 includes one antenna 60 or multiple antennas for receiving and transmitting wireless communication signals over communication channel 32. The antenna 60 includes a wireless device 64 and a modem 68.
The modem 28 is connected to the microprocessor assembly 72.

The microprocessor assembly 72 is, for example, Stron manufactured by Intel Corporation.
It may be equipped with a gARM processor, which performs various functions including performing A / D and D / A conversions, filters, encoders, decoders, data compressors / decompressors and / or performing packet disassembly. As shown in FIG. 3, the microprocessor assembly 72 interconnects a modem 68 and a data port 76, which allows the subscriber station 28 to process a data received through the communication channel 32, a personal computer, PDA (PDA). personal digita
Interconnect to intelligent devices such as l assistants. Therefore, the microprocessor assembly 72 includes a data port 76.
Data can be processed between the and the modem 68.

Referring to FIG. 4, a frame for transmission over the data channel 32 is indicated generally by the reference numeral 100. In the preferred embodiment, frame 10
0 was chosen to require a transmission time of 10 ms, but one that requires a longer or shorter transmission time can be chosen if desired.
As will be appreciated by those skilled in the art, frame 100 may be measured by a fixed amount of time. A predetermined number of symbols can be carried during that period. The symbols represent the data, and the actual amount of data represented by the symbol in one part depends on how the data is packaged in the symbol (typically packaged with a combination of modulation and coding). Dependent. Therefore, it should be understood that while the frame period and the symbol rate of the frame are kept constant, the effective data rate transmitted in the frame depends on the packaging of the data. The application of such a concept to the present invention is described in detail below.

The frame 100 includes a ring (that is, reception capability) packet 104, a header packet 108, and a plurality of payload packets 112 ₁ , 112 ₂ ,. ． ． , 112 _x . As mentioned above, depending on the packaging of the payload packets 112, the number "x" of payload packets in the frame 100 may vary, and factors affecting such variables are detailed below. To do.

The ring packet 104 is composed of a destination ring identifier field 116 and a frame length field 120. Preferably, the destination ring field and 116 are 2 bits in length and the frame length field 120 is 10 bits in length. The destination ring field 116 contains the outermost ring 36 containing at least one payload packet 112 destined for the subscriber station 28 whose frame 100 is located on the outermost ring 36, and is capable of receiving from the base station 24. Identify as the worst. For example, frame 100, which has a destination ring identifier field 116 corresponding to ring 36b, contains a subscriber station (28n
Can include a payload packet for 28a or 28b). The frame length field 120 includes payload packets 112 ₁ , 112 ₂ ,. ． ． , 112 _x containing the value “x”.

Unlike the payload packet 112, the destination ringfield 116 and the frame length field 120 are used by all the subscriber stations 28a, 28b ,. ． ． , 28n are always strongly packaged in the ring packet 104 so that they can be restored by the 28n. Such strong packaging allows all subscriber stations 28 served by base station 24 to restore fields 116, 120. In this example, the strength of the ring packet 104 is achieved as follows. Fields 116, 120 are inserted into ring packet 104 after undergoing FEC operation 124 and modulation operation 128. The type of FEC operation 124 is selected based on the requirements of the subscriber station 28n located on ring 36n (ie, the subscriber station 28 with the worst reception capacity).

For example, if the data channel 32 employs a CDMA multiple access technique, then preferably the subscriber station 28n has an E _s / I _o level of 3db and the preferred FEC operation 124 is a ratio 1/2. Coding, and the modulation operation 128 is 4QAM (
QPSK). Appropriate combination of FEC operation 124 and modulation operation 128 assists and / or guarantees not only the restoration of ring packet 104 by subscriber station 28n, but also the restoration of ring packet 104 by the remaining subscriber stations. The FEC operation 124 and the modulation operation 128 adapted to a given subscriber station 28n having a given reception capability will be readily apparent to those skilled in the art.

Table 1 illustrates exemplary packaging of the frame 100 in a CDMA system with various SNRs. The first column (Ec / No) is for a given subscriber station 28.
Is an SNR measurement showing the power per chip for a given noise level experienced by the. The second column (spreading factor) shows the number of chips per symbol. The third column (modulation symbol) indicates the modulation operation used for data packaging. The fourth column (coded bits / symbol) indicates the number of bits per symbol after undergoing the modulation operation of the third column. The fifth column (code rate) indicates the coding operation used for data packaging. The sixth column (symbol repetition factor) shows the factor by which the symbols are repeated to further package the data for strong reconstruction. 7th
The column (number of bits / symbol) shows the number of effective bits per symbol. The eighth column (bits / frame) shows the effective number of bits per frame under the assumption that all bits in the frame are packaged by the modulation rate, the coding rate and the symbol repetition factor shown in the same row. Show. The ninth column (E _s / N _o ) is the SNR measurement that indicates the power per symbol per given noise level experienced by a given subscriber station 28. 10 column (E _b / N _o) is a SNR measure of power per bit per predetermined noise level. Those skilled in the art will appreciate that the first, ninth and tenth columns are in a fixed relationship to each other.

Therefore, the preferred encoding operation 124 (see columns 5 and 6) and modulation operation 12
8 (see third column) are shown in Table 1. However, destination Ringfield 1
Other suitable means for strongly packaging 16 and frame length field 120 into ring packet 104 and / or combinations thereof will be apparent to those skilled in the art.

The header packet 108 includes a plurality of identifier fields 132 that contain identification information for each payload packet 112. In this embodiment, the identifier field 132 is the address field 136, the format field 14
0 and length field 144. The address field 136 contains any of the destination subscriber stations 28a, 28b ,. ． ． , 28n receive their respective payload packets. The format field 140 indicates the modulation and coding method used to prepare each payload packet 112 _x , which is described in detail below. The length field 144 indicates the length of each payload packet 112. Header packet 108 also includes each subscription for stations 28a, 28b ,. ． ． , 28n include a CRC packet 148 that can be used to determine whether the header packet 108 has been correctly received. Further, as will be apparent to those skilled in the art, a flash bit 152 is added to ensure recognition of the end of the header packet 108 during decoding.

Preferably, each address data field 136 is 12 bits long and each format data field 140 is 4 bits long.
Each length data field 144 is 12 bits in length, the CRC field 148 is 8 bits in length, and the flash bit 152 is 8 bits in length. However, it will be apparent to those skilled in the art that other lengths may be adopted to suit particular needs.

Identifier packet 132, CRC packet 148 and flush packet 15
2 is packaged in the header packet 108 in a suitably strong manner to ensure restoration by all subscriber stations 28 located between (including the ring) base station 24 and the destination ring field 116. It In other words, if the destination ring field 116 indicates the ring 36b, the contents of the header packet 108 are packaged for strong restoration by all subscriber stations 28 in the rings 36a, 36b, where in the ring 36b. The subscriber station 28n of the header packet 1
08 can be received.

In this embodiment, strong packaging of the header packet 108 is achieved in the following manner. Packet 132, CRC packet 148, and flush bit 152 undergo header operation 1 after encoding operation 158 and modulation operation 162.
08 is formed. The FEC operation 158 and the modulation operation 162 are selected based on the reception capability required to recover the header packet 108 by the subscriber station located in the ring indicated by the destination ring field 116. Preferably, the encoding operation 158 is a 1/3 ratio convolutional encoding and the modulation operation 162 is an M-ary QAM.
(Where M can be 4, 16, 64 or 256).

An appropriately selected combination of encoding operation 158 and modulation operation 162 is that the header packet 10 by the subscriber station 28 located in the ring indicated by the destination ring packet.
8 as well as subscriber stations 28 and base stations 24 located in between, help to ensure and restore header packet 108. Therefore, the preferred encoding operation 1
24 (see columns 5 and 6) and the modulation operation (see column 3) are shown in Table 1. However, packet 132, CRC packet 148 and flush bit 1
Other suitable encoding operations 158, modulation operations 162 and / or other means of strongly packaging 52 into header packet 108, and / or combinations thereof, will be apparent to those skilled in the art.

Each payload packet 112 is composed of one or more data packets 116 and flush bits 170. Each payload packet 112 has a base station 24
1 located between (including the ring) indicated by the destination ring packet 116 and
The destination is one or more subscriber stations 28. For example, the data packet 166 is TC
It may be a P / IP packet, but it is preferred here to transmit the IP packet to the subscriber station 28. The data packet 166 is for a particular subscriber station 28a, 28b,
． ． ． , 28n (each having its own unique address, one or more broadcast addresses may be defined).

The data packet 166 may be of any length (represented by the length field 144), and the data placed in the data packet 166 may be combined or divided into appropriate sizes as needed. You can In general, data packet 166 may include a portion of one or more packets designated for a single subscriber station 28. In this embodiment, the flash bit 170 having an 8-bit length is substantially the same as the flash bit 152 for the same reason as the data packet 16
It is added to the end of 0.

Each data packet 166 and its corresponding flash bit 170
Of the payload packets 112 ₁ , 112 ₂ ,. ． ． , 112 _x . Such packaging is strongly performed by the format indicated by the format field 140 for the payload packet 112. Such packaging aids and ensures recovery by the destination subscriber station 28 (note that the base station 24 and other subscriber stations 28 located between the ring in which the destination subscriber station 28 is located are also Although the payload packet 11 can be restored, such restoration is not generally performed, and appropriate security measures can be adopted to prevent interception). For example, if frame 100 includes a destination ring field 166 that defines transmission to ring 36n and includes payload packet 112 designated for subscriber station 28b, payload packet 112 is restored by subscriber stations 28a, 28b. It will be packaged for you to do. The particular forward encoding operation 174 and modulation operation 178 are performed by the subscriber station 2 located on the ring 36b indicated by the address data field 136 for the payload packet 112.
It is selected according to the reception capability of 8b. Preferably, the encoding operation 174 uses the ratio N
, Where N is a real number greater than 0, and the modulation operation 178 is M-ary QAM (where M can be 4, 16, 64 or 256). , N and M are the ring 36 indicated by the format field 140.
Selected to match the reception capability of the.

In general, the encoding operation 174 and / or the modulation operation 178 and / or other strong packaging may be performed by each payload 11 within a single frame 100.
It can be selected commonly or individually for the two. For example, if the subscriber stations 28 in a ring 36 have a wide range of reception capabilities, the common modulation operation 178 may be applied to each subscriber station 28 in that particular ring 36, but with a different encoding. Action 174
Can be applied to adjust the range of reception capability within the particular ring 36.

Encoding operation 174 and / or modulation operation 178 and / or other strong packaging choices for each payload packet 112 in frame 100 may include:
It may vary depending on the actual use and / or type of data conveyed through the data channel 32 (as the use and / or type of data may have different requirements in achieving the required packet error probability). For example, ftp (fi
The le transfer transmission is a VOIP (Voice).
over IP) connection has a lower error tolerance. Therefore,
Payload packet 1 transmitted to the first subscriber station 28 located on ring 36b
12 may be encoded with 1/4 convolutional coding and ring 36b
Payload packets to be transmitted to the other subscriber stations 28 located in the can be coded with 1/2 convolutional coding for the VOIP connection.

As will be appreciated by those skilled in the art, if the encoding operation 174 and the modulation operation 178 are common to the destination ring 116, eg, ring 36b, the higher ring,
For example, the payload packet 112 designated for the subscriber station 32 located on the ring 36a may optionally be included in the frame 100, even though packaged with an unnecessary level of strength corresponding to the designated destination. You can also

Currently, the preferred encoding operation 124 (see columns 5 and 6) and modulation operation 12
8 (see third column) are shown in Table 1. However, other suitable encoding operations 174, modulation operations 178 and / or other means, and / or combinations thereof, that strongly package the data packet 166 and the flash bit 170 into the respective payload packet 122 are well known to those skilled in the art. Would be obvious to him.

Referring to FIG. 5, a data transmission method according to an embodiment of the present invention is shown. For convenience of description, the network 20 and the frame 100 will be referred to. In step 200, the data packet 166 transmitted to one or more subscriber stations 28 is transmitted to the base station 2
4 and buffered until a sufficient amount of data to fill frame 100 is received. In this example, the data packet 166 is received at the base station 24 through the backhaul 56 or from another subscriber station 28 that transmitted the data packet 166 to the base station 24, and the microprocessor router assembly 52 determines the data to be assembled into frame 100. Buffer the packet 166. As will be appreciated by those skilled in the art, the amount of data sufficient to fill the frame 100 is determined by the selected encoding operations 158, 174 and the selected modulation operations 162,
178. Thus, there is a sufficient amount of data at the end of the preselected period from the time of receiving the first data packet 166, indicating the best (ie, most effective of data rate) coding and modulation operation. Is received and the latter parameter is used to ensure that frame 100 is assembled and transmitted before the preselected maximum latency period is exceeded. Encoding and / or modulation operations buffer received data that could not be placed in the assembled frame 100 due to inefficient data rates and are assembled in a timely manner in the next frame 100.

Once a sufficient amount of data has been received to fill frame 100, in step 204 at least one received data packet is addressed to subscriber station 2
The ring 36 having the worst reception ability including 8 is determined. Step 204 is performed by the microprocessor router assembly 52, which
Inspect each destination address of the received data packet 166 for at least 1
Base station 24 including subscriber station 28, which is the destination for one data packet 166
From this, the ring 36 having the worst reception capability is determined.

In step 208, the payload packet 112 is assembled into a frame 1
Insert at 00. Appropriate encoding operations 174 and modulation operations 178 are applied to the received data packet 166, appropriate flash bits 179 are added and inserted into one or more payload packets 112. Data packets 166 destined for the same subscriber station 28 can be grouped and inserted into one or more common payload packets 112.

Depending on the ring 36 determined in step 204, a modulation operation 178 may be selected for all processed packets 166 (ie, if the determined ring is 36a, all 256QAM is applied to all packets and 64QAM is applied to all packets if the determined ring is 36b), or, as mentioned above, the modulation operation applied to packet processing is If desired, it can be changed for each packet and applied. Similarly to this, step 2
Depending on the ring 36 determined at 04, the encoding operation 174 may be selected for all processed packets 166 (ie for all packets if the determined ring is 36a). If ratio 1/2 coding is applied and the determined ring is 36b, ratio 1/4 coding is applied for all packets) or the code applied to packet processing as described above. The conversion operation can be changed for each packet and applied as desired. Currently frame 1
Apply a single modulation operation 178 to all packets 166 in 00 and encode depending on the difference in receiving capabilities of subscriber stations located in ring 36 and / or depending on the desired packet error probability. The operation 174 is adapted to be applied differently.

Once the payload packet 112 is assembled, the header packet 108 is assembled and inserted into the frame 100 in step 212. The header packet 108 inserts the destination subscriber station 28 for each payload packet 112 into each address field 136 and the format (ie, modulation and / or coding) for each payload packet 112 as described above in the format field 140. , And the length for each payload packet 112 is inserted in each length field 144. Finally, such an identifier packet 132 is used to generate a CRC code and
Insert in field 148. A flash bit 152 is then added, at which time fields 132, 148 and flash bit 152 are encoded operation 1
It is encoded according to 58 and modulated according to the modulation operation 162. Encoding operation 15
8 and the modulation operation 162 are selected such that the header packet 108 is strongly packaged for the receiving capabilities of all subscriber stations 28 located in the ring 36 determined in step 204.

Next, in step 216, the ring packet 104 is assembled. The outermost destination ring 36 determined in step 204 is inserted into the destination ring field 116 and the frame length associated with the number "x" of payload packets is inserted into the frame length field 120. Then field 116
, 120 are forward error corrected using FEC operation 124, modulated using modulation operation 128, and then inserted into ring packet 104. Operations 124, 128 are selected such that ring packet 104 is strongly packaged for a high level of probability of reception by all subscriber stations 28 served by base station 24.

Then, in step 220, the assembled frame 100 is transmitted to the subscriber station through the data channel 32. Such transmission is performed in a usual manner using a known technique.

Of course, those skilled in the art can modify and implement the above method within the scope of the present invention. For example, in step 204, the determined predetermined destination ring 36.
In contrast, if the modulation operation 178 and the encoding operation 174 are preselected, then determining the amount of received data sufficient to fill the frame 100 is straightforward and may be determined when each data packet 166 is received. . In such a case, step 204
Is performed upon receipt of each packet 166, at which time the ring 36 with the worst reception capacity is determined for all received packets. Received data packet 166 is scaled in response to a defined modulation and coding operation, and the scaled data magnitude is compared to the selected maximum frame 100. If the defined maximum frame size or the predefined maximum latency period has not been exceeded, the next received packet 166 is inspected to update the ring 36 with the worst reception capacity, if necessary. The scaling operation is performed again, and the magnitude (and / or latency time) is re-examined.

Referring to FIG. 6, a frame 100 transmitted by a subscriber station 28 according to an embodiment of the present invention.
Is shown how to restore. In step 300, the subscriber station 28 receives the frame 100. The wireless device 64 receives the frame 100 and receives the frame 6
Propagate to 8.

In step 304, the destination ring packet 104 is restored. In this embodiment, this is a modem 68 using demodulation operations for modulation operations 128,
This is accomplished by microprocessor assembly 72 using a decoding operation that corresponds to FEC operation 124. In this embodiment, the demodulation operation and the decoding operation are defined in advance for all the subscriber stations 28, and the network 20
The ring packet 104 can be restored even under the worst reception capacity in the inside. Once the ring packet 104 is restored, the microprocessor assembly 72 will use the destination ring field 116 and the frame length field 120 to help further process the frame 100 as described below.

At step 308, whether the subscriber station 28 is located in or on the destination ring 36 indicated by the destination ring field 116 (ie, the receiving capability of the subscriber station 28 is at least that of the ring indicated by the destination ring packet 116). Is the same as the receiving capability). If it is determined in step 308 that the receiving capability of the receiving subscriber station 28 is worse than the receiving capability of the ring indicated by the destination ring field 116, the frame is discarded in step 312, and the process returns to step 300 to return to the next frame 100. Receive and process.

However, at step 308, if the receiving capability of the receiving subscriber station 28 is determined to be at least equal to the receiving capability of the ring 36 indicated by the destination ring field 116, the one or more payload packets 112 in the frame 100 are Addressed to subscriber station 28 and proceed to step 316.

In step 316, the destination header packet 108 is restored. In this embodiment, this is a modem 68 that uses a demodulation operation corresponding to the modulation operation 162.
And by the microprocessor assembly 72 using a decoding operation corresponding to FEC operation 158. In this example, step 304
An appropriate demodulation operation and / or decoding operation is determined based on the information included in the destination ring 116 restored in step 1.
It can be fixed within 0. Such an operation makes it possible to restore the header packet 108 with a high success rate even in the subscriber station 28 having the worst reception capacity on the ring 36 indicated by the destination ring field 116.

Next, in step 320, it is determined here whether the CRC packet 148 restored from the header packet 108 is valid for the restored header packet 108. Header packet 108 in which CRC packet 148 is restored
Is not valid (i.e., when a reception error occurs), it is determined that the receiving subscriber station 28 has not correctly restored the header packet 108, and the process proceeds to the exception processing step 324. Sending a NACK, as will be apparent to those skilled in the art, or
All exception handling protocols can be used, including no explicit exception handling behavior.

If it is determined in step 320 that the restored CRC is valid, the receiving subscriber station 28 determines that the header packet 108 has been restored correctly, and step 3
Proceed to 28. At step 328, the payload packet 112 addressed to the receiving subscriber station 28 is restored. The microprocessor assembly 72
Each identifier packet 131 ₁ ,. ． ． , 132 _x , any of the payload packets 112 ₁ , 112 ₂ ,. ． ． , 112 _x are addressed to the receiving subscriber station 28. These payload packets 112, addressed to the receiving subscriber station 28, are decoded operations corresponding to the encoding operations 174 shown in the format field 140 in the packet 132 or predefined in the network 20 and It is restored from frame 100 by a demodulation operation corresponding to modulation operation 178.

[0056]   Then, in step 300, the next received frame 100 is processed.

The present invention is particularly suited for the transmission of conference data (audio or video), because one or more payload packets 112 within frame 100 are addressed (eg payload packet 112). (Including address information indicating all subscriber stations 28 in the call that must be restored) can be restored by multiple subscriber stations 28 participating in the conference. The payload packet may include conference data. Data packaging ensures that subscriber stations with a medium level of reception can recover (providing subscriber stations with low levels of reception with some acceptable loss of payload data 112, It will be clear that it can be robustly packaged, providing reliable restoration for subscriber stations with a high level of reception. Unlike this, the subscriber station 2 that participated in the conference call
The data channel 32 can be easily set for only one of the eight groups.

It should be apparent that the embodiments described above are illustrative embodiments of the present invention, and that combinations, sub-settings and modifications of the embodiments are possible within the scope of the present invention. For example, data packets 166 received through backhaul 56 or other subscriber stations 28 may be buffered at base station 24 to organize the frames into a desired format, eg, rings 36a, 36b ,. ． ． , 36n, the frames can be grouped.

The buffering of data packets 166 at the base station 24 also refers to the size of the frame (ie, the amount of symbols within a frame of a predetermined predetermined time length).
, Because of the modulation and / or coding and / or FE actually needed to assemble each packet in the frame.
This is because the amount of C can be selected as desired.

Also, additional channels can be provided to the network 20 as desired. For example, any one channel is connected to any one group of rings 36a.
,. ． ． , 36c, and other channels as ring 36
d ,. ． ． , 36n. Additionally or alternatively, additional channels may be encrypted to improve the security of transmissions over network 20.

Also, additional channels can be added to accommodate subscriber stations with newer and faster wireless devices than other subscriber stations on the network 20. In this embodiment, the newer and faster subscriber stations 28 described above are compatible with the backhaul and include the ability to accommodate previous channels and additional channels.

Also, by providing additional channels, latency can be easily improved on the network 20, thereby increasing the overall data throughput from the base station to the subscriber stations. Become. In addition, the base station 24 buffers the packet to classify the data and the related QoS (Quality of Serv).
ice) The data can be adjusted according to the requirements. For example, data associated with a web browser can be buffered and transmitted with relatively unrestricted latency, where possible, and data associated with a VOIP connection can transfer that latency to such a connection. It can be transmitted on a priority basis to reduce to the required low level.

In addition, additional base stations 24 can be added to the network 24, which allows the processing of the network 20 by applying known soft-handoff or similar techniques to the network 20. The quantity and overall capacity can be further improved.

The network can also be divided into multiple service classes (ie, rings) and within each respective service class one or more sub-service classes (or sub-rings). In such a case, a predetermined level of modulation can be applied to each service class and a predetermined level of error correction can be applied to each of the lower service classes.

Although the above embodiments use a combination of coding and modulation to strongly package a frame and / or a portion thereof in response to different desired receiving capabilities of different subscriber stations, Other strong packaging means can be used if desired.

Also, the strong packaging (ie, modulation and / or coding) format used to package the packets within frame 100 can be determined in a variety of ways. For example, each subscriber station 28 may report their reception capabilities (either by indicating the ring 36 in which the subscriber station 28 is currently located or by an accurate measurement) to the base station 24. The payload packet 112 can then be packaged (i.e., encoded and / or modulated) with the received capabilities reported in a predetermined format known by the base station 24 and the subscriber stations 28. In this way, the base station 24 need not provide the format field 140 to each subscriber station 28 because the subscriber station 28 simplifies the associated payload packet 112 by a predetermined format. This is because it can be decoded into. What is clear above is that the format field 140 can be removed.

In contrast to this, the format field 140 is included in the frame 100, which further comprises control bits, which control the payload packet 112 addressed to a given subscriber station 28. Indicates that the payload packet 112 is packaged according to a predetermined format based on the reception capability of the payload packet 112 or the payload bit 112 is dependent on some other format indicated by the next bit in the format field 140. Can be shown as packaged.

Also, the format field 140 can be removed because “blind detection” can be used to determine a strong packaging format by the receiving subscriber station 28. That is, the receiving subscriber station 28 can simply attempt to decode the payload packet 112 with varying levels of demodulation and decoding until the data packet 116 is significantly restored. It will be apparent to those skilled in the art that other combinations and modifications of selecting and detecting strong packaging types are possible.

Although the above embodiments show multiple access schemes performed over the air, the present invention is applicable to various connection schemes, eg, twisted pair or coaxial links, and TD.
Methods such as MA, FDMA or CDMA can be used.

The present invention provides a novel data channel for a network having at least one base station and multiple subscriber stations. This data channel may consist of a plurality of frames with at least one packet readable by all subscriber stations indicating whether the receiving subscriber station has been addressed to all or part of the frame. The frame and / or part of it is strongly packaged in an appropriate manner, the addressed subscriber station recovers the data addressed to it and the unaddressed subscriber station: Help or guarantee that it is not necessary to recover all or part of the data contained in the frame.
By strongly packaging a frame and / or part of it with different reception capabilities of different subscriber stations, less complex strong packaging can be applied to poor reception subscriber stations. , This ensures that more data is packaged in each frame and that the network packages the frames in a more powerful manner to reach subscriber stations with better reception requirements.

The above-described embodiments are merely examples of the invention, and the invention is not limited thereto and can be modified by those skilled in the art without departing from the scope of the invention.

[0072]

[Table 1]

[0073]

[Brief description of drawings]

[Figure 1]     1 is a schematic diagram of a network including a data channel according to an embodiment of the present invention.

[Fig. 2]     It is a schematic diagram of the base station shown in FIG.

[Figure 3]     FIG. 2 is a schematic diagram showing one of the subscriber stations shown in FIG. 1.

[Figure 4]     2 is a schematic view of a frame transmitted through the network shown in FIG. 1. FIG.

5 is a flowchart illustrating a method of assembling and transmitting the frame of FIG. 4 according to another embodiment of the present invention.

6 is a flowchart illustrating a method of receiving and restoring the transmitted frame of FIG. 4 according to another embodiment of the present invention.

─────────────────────────────────────────────────── ─── Continued front page    (81) Designated countries EP (AT, BE, CH, CY, DE, DK, ES, FI, FR, GB, GR, IE, I T, LU, MC, NL, PT, SE, TR), OA (BF , BJ, CF, CG, CI, CM, GA, GN, GW, ML, MR, NE, SN, TD, TG), AP (GH, G M, KE, LS, MW, MZ, SD, SL, SZ, TZ , UG, ZW), EA (AM, AZ, BY, KG, KZ, MD, RU, TJ, TM), AE, AG, AL, AM, AT, AU, AZ, BA, BB, BG, BR, BY, B Z, CA, CH, CN, CR, CU, CZ, DE, DK , DM, DZ, EE, ES, FI, GB, GD, GE, GH, GM, HR, HU, ID, IL, IN, IS, J P, KE, KG, KP, KR, KZ, LC, LK, LR , LS, LT, LU, LV, MA, MD, MG, MK, MN, MW, MX, MZ, NO, NZ, PL, PT, R O, RU, SD, SE, SG, SI, SK, SL, TJ , TM, TR, TT, TZ, UA, UG, US, UZ, VN, YU, ZA, ZW (72) Inventor Kushiang, Frank             Canada M5 buoy 1 are 2 on             Toronto Suite 700, Tario             Delade Street West 312 (72) Inventor Fraser, Mark, James             Canada M5 buoy 1 are 2 on             Toronto Suite 700, Tario             Delade Street West 312 (72) Inventor Mansa, Ramesh             Canada M5 buoy 1 are 2 on             Toronto Suite 700, Tario             Delade Street West 312 (72) Inventor Van Heathwick, Frank, Em.             Canada M5 buoy 1 are 2 on             Toronto Suite 700, Tario             Delade Street West 312 F term (reference) 5K067 AA13 AA23 BB02 BB21 CC08                       CC10 DD13 DD17 DD41 EE02                       EE10 EE16 FF03 FF16 GG03                       GG06 HH22 HH23 HH24 JJ15                       JJ17 KK13 KK15

Claims (23)

[Claims] 1. In a data transmission system, a base station comprising a microprocessor, a modem and an output device for signal output, and a microprocessor, a modem and an input device, different from at least one other subscriber station. A plurality of subscriber stations receiving the signal with reception capability, the signal being irrespective of the reception capability with an identifier recoverable by all the subscriber stations and at least one of the subscriber stations. A data transmission system, comprising a frame having a rest part that can be restored, wherein the identifier indicates whether the subscriber station needs to restore the rest part. 2. The system according to claim 1, wherein the output device and the input device are wireless devices, and the signals are wireless transmission signals. 3. The system of claim 1, wherein the signal is transmitted over a CDMA channel. 4. The identifier indicates a range of reception capability, the remaining portion includes a header having address information, the header being recoverable by the subscriber station within the range and the remaining portion. The system of claim 1, further comprising at least one payload packet recoverable by a subscriber station corresponding to the address information. 5. The system of claim 2, wherein the payload packet is packaged according to the receiving capability of the receiving subscriber station. 6. The system of claim 1, wherein the receiving capability is a measure of signal to noise ratio. 7. The system of claim 1, wherein the identifier is packaged within the frame using a modulation operation. 8. The system of claim 1, wherein the identifier is packaged within the frame using an encoding operation. 9. The system of claim 1, wherein the remaining portion is packaged within the frame using a modulation operation. 10. The system of claim 1, wherein the remaining portion is packaged within the frame using a combination of encoding and modulation operations. 11. The system of claim 10, wherein the encoding operation is a 1 / N ratio convolutional encoding. 12. The system of claim 10, wherein the modulation operation is M-ary QAM. 13. The system of claim 1, wherein the remaining portion is packaged within the frame using an encoding operation. 14. A data transmission system, comprising a base station including a microprocessor, a modem, a wireless device and an antenna, and a microprocessor, a modem, a wireless device and an antenna, and transmitting from the base station with a first reception capability. At least a first subscriber station capable of receiving a wireless signal, a microprocessor, a modem, a wireless device, and an antenna, capable of receiving the transmitted wireless signal with a second receiving capability different from the first receiving capability. One additional subscriber station, the base station is capable of strongly packaging a data frame over a channel for reception by all the subscriber stations, a portion of the frame being It is restored by all subscriber stations and indicates whether the receiving subscriber station restores the rest of the frame. A data transmission system characterized in that 15. An antenna radio device assembly for receiving a radio signal carrying a frame transmitted from a base station with an arbitrary reception capability, the frame connected to the antenna radio device assembly regardless of the reception capability. To a modem microprocessor assembly for restoring an identifier indicating whether the microprocessor needs to restore the rest of the frame packaged according to the receiving capability. Subscriber station. 16. A method of packaging a frame for transmission to at least one of a plurality of subscriber stations over a multi-connection link, wherein each subscriber station is capable of receiving a transmission signal over the link. A method of packaging a frame having a receiving capability associated with: receiving and buffering a sufficient amount of data to fill the frame; addressing the data to the at least one subscriber station. And strongly packaged according to the receiving capability of said at least one subscriber station
Assembling in one payload packet, assembling the address of the at least one subscriber station in a header packet that is strongly packaged according to the receiving capability of the at least one subscriber station, and the at least one At least one addressing one payload packet
Constructing an identifier indicating the worst receiving capability of one subscriber station and recoverable by all subscriber stations regardless of said receiving capability; and assembling the payload packet, the header and the class identifier in a frame And a step of transmitting the frame through the link, the packaging method of the frame. 17. The method further comprising, prior to the transmitting step, assembling format information in the header that indicates how strongly the at least one payload packet is packaged. 18. A method for packaging a frame according to item 18. 18. A method for recovering a frame transmitted from a base station to a plurality of subscriber stations through a multi-connection link, wherein each subscriber station has a receiving capability associated with the multi-connection link. In a certain frame restoration method, a step of receiving the transmitted frame, a step of restoring an identifier using a restoration operation corresponding to the worst reception capability of the subscriber station, and the identifier being the receiving subscriber station. Is within the range of the receiving capability, the step of restoring the header packet restored using the restoring operation corresponding to the worst receiving capability indicated by the identifier packet, the header packet being the receiving subscriber. The payload packet restored by a restore operation corresponding to the receiving capability of the station is addressed to the receiving subscriber station. And a step of recovering the payload packet when indicating that the frame is recovered. 19. In a frame transmitted to a plurality of subscriber stations having a receiving capability corresponding to the ability to restore the transmission signal, the receiving subscriber station is packaged so as to be restored regardless of the receiving capability. Is included in the range of reception capability, an identifier including information indicating that the header is packaged to be restored by a subscriber station that is within the range, and includes address information, and the address information indicates At least one payload packet packaged to be recovered by the at least one subscriber station; 20. The frame of claim 19, wherein the header further includes format information indicating a packaging format of the at least one payload packet. 21. The header is formatted according to (a) a packaging format of the at least one payload packet, and (b) a predetermined packaging format in which the at least one payload packet is known to the subscriber station. The frame according to claim 19, further comprising format information including any one of indicators indicating that the frame is to be played. 22. The packaging format of claim 21, wherein the packaging format includes any one of a modulation operation and an encoding operation used to package the at least one payload packet. flame. 23. The identifier is packaged to be restored in response to an error rate that is an order of magnitude lower than a target error rate for the frame.
The frame according to item 9.