JP2008109618A - Radio communication apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a radio communication apparatus using OFDMA (orthogonal frequency division multiplexing access) capable of maintaining speech quality of each subscriber without decreasing the number of accommodated subscribers even when a subchannel with inferior line quality is present. <P>SOLUTION: The radio communication apparatus includes: a voice detection means 26 which determines whether input voice data are voiced or voiceless and outputs voiced/voiceless information; a data burst generating means for generating a data burst from the input audio data; a subchannel line quality measuring section 25 for measuring line quality of each subchannel; and a scheduling processing section 24 which controls to preferentially allocate a subchannel with excellent line quality to a data burst of which the voiced/voiceless information output from the voice detecting means 26 indicates that the input audio data are voiced. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention uses OFDMA (Orthogonal Frequency Division Multiplexing access) as a multiple access scheme, and has a two-dimensional frame structure in which one axis is an OFDMA symbol number and the other axis is a subchannel number. And a radio communication apparatus having scheduling means for assigning subchannels to data bursts of voice signals in the time domain.

  OFDM (Orthogonal Frequency Division Multiplexing) is the terrestrial digital TV broadcast in Japan and Europe, ADSL, IEEE802.11a of high-speed wireless LAN standard, and WiMAX, etc. Adopted in communication applications.

  OFDM achieves high frequency efficiency by using a plurality of subcarriers (subcarriers) having different center frequencies. This is a multiplex communication method in which data to be transmitted is divided finely and transmitted in parallel on a plurality of subcarriers. By dividing the data, the symbol transmission rate per subcarrier can be made slower than in the case of serial transfer, and a pilot signal used for phase correction or the like can be inserted. For this reason, it is possible to reduce the influence of fading (a phenomenon in which the signal strength and the like change greatly in time and space in wireless communication) as a whole. In addition, transmission is performed orthogonally to each other so that interference does not occur even if the bands of adjacent subcarriers are overlapped so as to overlap each other. In addition, OFDM uses a “guard interval” that sends data with some overlap in time. Even if a signal (ghost) that has a time shift due to diffuse reflection or the like arrives at the receiving point, it is multipath. A system that does not cause failures can be realized. This feature is one of the main reasons why OFDM is adopted in terrestrial digital TV broadcasting where multipath is likely to occur.

  OFDMA (Orthogonal Frequency Division Multiple Access) divides a carrier into a plurality of subcarriers like OFDM, but differs from OFDM in that the divided subcarriers are grouped. A subcarrier within a group is called a subchannel, and a single subscriber may occupy these subchannels, or a plurality of subscribers may share a subchannel.

  WiMAX will be described as a system that employs OFDMA. The WiMAX wireless access system is defined as a standard in Non-Patent Document 1.

  FIG. 3 is an explanatory diagram showing an example of a physical layer of a WiMAX base station (BS) wireless communication apparatus using conventional OFDMA. In FIG. 3, functions that are not directly related to the present invention, such as synchronization processing, channel estimation, equalization processing, and power control, are omitted. The description will be made on the assumption that the communication data is an audio signal.

  First, transmission processing will be described.

  One of the transmission voice data al and the allocation information ql, which are transmission data to the subscriber, is selected by the switch 11 and input to the physical layer processing of the BS (base station) radio communication apparatus. Here, the allocation information ql includes the following three pieces of information (details will be described later).

[1] FCH (Frame Control Header)
[2] DL-MAP (Downlink MAP)
[3] UL-MAP (Uplink MAP: Uplink allocation information)
Further, the transmission voice data al to the subscriber includes data for a plurality of subscribers who are communicating. Here, both the transmission voice data al and the allocation information ql to the subscriber are PDUs (Protocol Data Units: protocol data units) output from the MAC layer, and the PDUs are the MAC header, payload, CRC (Cyclic Redundancy Check: CRC). Error detection code).

  In FIG. 3, the random burst processing unit 12 to the modulation mapping 15 constitute a data burst generation unit.

  The output bl of the switch 11 is input to the randomization processing unit 12. The purpose of randomization is as follows.

  (1) Reduce the number of unmodulated carriers so that transmission can be performed efficiently.

  (2) Ensure that enough bits are required for clock recovery.

  The randomized data cl is then input to the error correction coding processing unit 13 and subjected to error correction coding. As error correction, convolutional coding, which is random error correction coding, is used. Bit interleaving processing unit 14 performs bit interleaving on data dl that has been subjected to error correction coding in order to convert a burst error into a random error. Thereafter, the modulation mapping processing unit 15 maps the bit interleaved data el to signal points using a modulation scheme such as QPSK or 16QAM, and outputs a transmission symbol sequence fl.

  The transmission symbol sequence fl is input to the OFDMA multiplexing processing unit 16 as a data burst. Here, it has been described above that the transmission voice data al includes data for a plurality of subscribers that are communicating, but each data burst is transmitted to each subscriber terminal (SS: Subscriber Station). Corresponds to the transmission data string.

  The OFDMA multiplexing processing unit 16 performs processing for finely dividing the transmission symbol sequence fl and transmitting it in parallel on a plurality of subcarriers. In OFDMA, the divided subcarriers are grouped, the subcarriers in the group are called subchannels, and the subchannels are allocated to the subscribers so that the plurality of subscribers share the subchannels. The frame structure of OFDMA has a two-dimensional structure in which the horizontal axis is an OFDMA symbol number and the vertical axis is a subchannel number. Details of the frame structure will be described later. Subchannel allocation to data bursts on the OFDMA frame is adaptively performed in the time domain based on allocation information ql that is output from a scheduling processing unit 24 described later.

  Thereafter, the transmission signal gl multiplexed by OFDMA is processed by the transmission RF unit 17. The transmission RF unit 17 includes a transmission filter, an orthogonal modulation processing unit that up-converts the transmission carrier frequency, a power amplifier, and a transmission antenna.

  A transmission signal hl that is an output of the transmission RF unit 17 is transmitted to an SS (Subscriber Station).

  Next, processing of the receiving system will be described.

  A reception signal il transmitted from the SS and affected by fading, interference, and the like on the transmission path is input to the reception RF unit 18.

  The reception RF unit 18 includes a reception antenna, an LNA, an orthogonal demodulation processing unit that down-converts a reception signal to a baseband frequency, and a reception filter.

  An output signal jl from the reception RF unit 18 is divided into reception signals (corresponding to data bursts) kl for each subscriber by an OFDMA division processing unit 19 based on allocation information ql which is an output from a scheduling processing unit 24 described later. The The subsequent processing is executed for each received signal for each subscriber.

  A reception symbol string kl that is a reception signal for each subscriber is converted into a reception bit string ll by the demodulation demapping processing unit 20. Thereafter, the received bit string 11 is bit deinterleaved by the bit deinterleave processing unit 21, and a bit string ml in which a burst error is converted into a random error is output. Next, the error correction decoding processing unit 22 performs error correction decoding on the bit string ml. Viterbi decoding is used as error correction decoding, and a bit string nl subjected to error correction decoding is output. The randomization restoration processing unit 23 performs a process reverse to the randomization on the bit string nl, and the received voice data ol is output.

  Scheduling of the scheduling processing unit 24 is a function that adaptively assigns subchannels to data bursts in the time domain, but a specific scheduling method is defined in order to allow a vendor to be unique. It is assumed that it is performed in a layer higher than the MAC layer. The allocation information ql that is a scheduling result includes the following three pieces of information.

  [1] FCH (frame control header): Defines the profile of the subsequent downstream burst. Specifically, a DL-MAP profile (type of error correction code used in DL-MAP, DL-MAP message length, etc.) is shown.

  [2] DL-MAP (downlink allocation information): Data burst mapping information in downlink subframe (frame number, frame length, start OFDMA symbol number of each data burst, start subchannel logical number, and transmission of each data burst) The number of OFDMA symbols necessary for the transmission) and the physical layer profile (modulation scheme, error correction coding scheme, coding rate, etc.) of each data burst in the downlink subframe.

  [3] UL-MAP (uplink allocation information): data burst mapping information in uplink subframes (starting OFDMA symbol number of each data burst, starting subchannel logical number, OFDMA required for transmitting each data burst) And the physical layer profile (modulation method, error correction coding method, coding rate, etc.) of each data burst in the uplink subframe.

  FCH, DL-MAP, and UL-MAP are broadcast to all SSs (subscriber terminals).

  FIG. 4 is an explanatory diagram showing the frame structure of OFDMA. FIG. 4 shows an OFDMA frame structure of TDD (Time Division Duplexing) system. A frame n indicated by an index n includes a downlink (DL) subframe and an uplink (UL) subframe. The horizontal axis indicates the OFDMA symbol number (the index at the beginning of the frame is indicated as k), and the vertical axis indicates the subchannel logical number. Here, the subchannel logical number will be described. In OFDMA, after the divided subcarriers are grouped (subcarriers in the group are called subchannels), data transmission carriers, pilot carriers used for phase adjustment, guard bands, etc. for each subchannel A null carrier to be used is assigned to each of the groups. A subchannel logical number is a group in which a number starting with an index s is assigned to only a subchannel assigned to a data transmission carrier for each group.

  TTG (Transmit / Receive Transition Gap) is a transmission / reception switching gap, and RTG (Receive / Transmit Transition Gap) is a reception / transmission switching gap.

  The assignment of each burst to the frame structure will be described below. The preamble used for frame synchronization, carrier recovery, clock recovery, etc. is arranged at the beginning of the frame, and then arranged in the order of FCH, DL-MAP, and UL-MAP. The arrangement rule starts from the OFDMA symbol number k and the subchannel logical number s, and is arranged in order so that the subchannel logical number increases by one. When s + 15 is reached, the process proceeds to the next OFDMA symbol number.

  The remaining part of the downlink subframe consists of data bursts for individual SSs. Each data burst is assigned an allocation area defined by DL-MAP and a modulation scheme, error correction coding scheme, and coding rate according to the burst profile. In FIG. 4, downlink bursts # 1 to # 14 are shown for downlink data bursts. Each data burst assignment starts with the smallest OFDMA symbol number and smallest subchannel logical number that have not yet been assigned, and is assigned in increments of 2 symbols in the increasing direction of the OFDMA symbol number, reaching the last symbol in the data region. If so, it is assigned by folding back to the smallest OFDMA symbol number of the next subchannel logical number. In FIG. 4, for simplicity, each data burst is drawn to end with the last symbol in the data area. Further, although it is possible to assign a plurality of SSs to each downlink data burst, in the following description, it is assumed that one SS is assigned to one data burst for simplicity.

  After the downlink subframe, the uplink subframe starts with a TTG (gap for transmission / reception switching).

  The uplink subframe is composed of data bursts for individual SSs. Each data burst is assigned an allocation area defined by UL-MAP and a modulation scheme, error correction coding scheme, and coding rate according to the burst profile. In FIG. 4, uplink data bursts are indicated as uplink bursts # 1 to # 14. Each data burst assignment starts with the smallest OFDMA symbol number and smallest subchannel logical number that have not yet been assigned, and is assigned in increments of 3 symbols in the increasing direction of the OFDMA symbol number, reaching the last symbol in the data region. If so, it is assigned by folding back to the smallest OFDMA symbol number of the next subchannel logical number. In FIG. 4, for simplicity, each data burst is drawn to end with the last symbol in the data area. At the end of the uplink data burst, a ranging subchannel is assigned. The ranging subchannel is a channel for performing ranging in order to adjust the communication timing and transmission output between the BS and the SS. The SS uses the ranging subchannel specified by the BS to communicate with the BS. The transmission timing, output and frequency are adjusted while repeating the above.

  The subchannel line quality measurement unit 25 performs measurement for each burst for the purpose of selecting an uplink burst profile and performing uplink power control. Here, RSSI (Receive Signal Strength Indicator) and CINR (Carrier-to-Interference-and-Noise Ratio) for each burst from the received signal rl for each subchannel output from the OFDMA division processing unit 19. ) And the like are measured and input to the scheduling processing unit 24 as subchannel line quality information pl.

  When voice communication is performed by the BS wireless communication apparatus, the PCM method is generally widely used as a voice encoding method. In addition, as a voice encoding method applied to transmission voice data al that is input to the BS radio communication apparatus, one subscriber is ITU-TG.726 (ADPCM), and another subscriber is ITU-TG. A plurality of different schemes may be used such as 729 (CS-ACELP). Then, voice encoded information is transmitted / received by the BS wireless communication apparatus every frame length of 10 msec. Corresponding to this, the OFDMA frame length is 10 msec. In FIG. 4, subscribers # 1 to # 14 are assigned downlink bursts # 1 to # 14 on the downlink and uplink bursts # 1 to # 14 on the uplink. To do.

In addition, there exist patent documents 1-5 as a well-known technique relevant to this invention.
JP 2006-180374 A JP 2006-141038 A JP 2006-094005 A JP 2006-066752 A JP 2003-018117 A IEEE Std 802.16-2004, “Part 16: Air Interface for Fixed Broadband Wireless Access Systems”, 2004, [online] Internet <URL: http://standards.ieee.org/getieee802/802.16.html>

  In voice communication, real-time performance is required, so that the function of ARQ (Automatic Repeat Request) cannot be used as in data communication. For this reason, the call quality of a subscriber who uses a data burst assigned to a subchannel with poor line quality cannot be maintained. If the subscriber's voice coding method using data bursts assigned to subchannels with poor circuit quality is a method with low transmission error tolerance (for example, ADPCM), the call quality is It cannot be maintained. In addition, there is a problem in that the number of accommodated subscribers decreases when scheduling is performed so as not to use subchannels with poor line quality in order to maintain subscribers' call quality.

  The present invention has been made in view of the above circumstances. Based on the subchannel line quality information, the subchannel has good line quality, the sound / silence information is sound, or the transmission error tolerance information is low resistance. By performing scheduling to control data bursts with priority, even when there are subchannels with poor channel quality, it is possible to maintain the call quality of each subscriber without reducing the number of subscribers accommodated. An object of the present invention is to provide a wireless communication apparatus that uses OFDMA (Orthogonal Frequency Division Multiple Access).

  In order to achieve the above object, the present invention uses OFDMA (Orthogonal Frequency Division Multiple Access) as a multiple access scheme, and is a two-dimensional frame configured with an OFDMA symbol number on one axis and a subchannel number on the other axis. A wireless communication apparatus having a structure and assigning a subchannel to a data burst of a voice signal in a time domain, determining whether input voice data is voiced or silent, and providing voiced / silent information Voice detecting means for outputting, data burst generating means for generating data bursts from the input voice data, subchannel line quality measuring means for measuring the channel quality of each subchannel, and output from the subchannel line quality measuring means On the basis of the subchannel channel quality information, a subchannel with good channel quality is output as voiced / silent information as an output from the voice detecting means. There is characterized in that it comprises a scheduling means for controlling to assign a priority to the data burst indicating a sound.

  In addition, the present invention uses OFDMA (Orthogonal Frequency Division Multiple Access) as a multiple access scheme, and has a two-dimensional frame structure in which one axis is an OFDMA symbol number and the other axis is a subchannel number. A wireless communication apparatus for performing subchannel allocation to signal data bursts in a time domain, detecting a type of speech encoding method of input speech data, and outputting transmission error resilience information; and Data burst generation means for generating data bursts from input voice data, subchannel line quality measurement means for measuring the channel quality of each subchannel, and subchannel line quality information that is output from the subchannel line quality measurement means On the basis of the transmission error tolerance information, which is an output from the transmission error tolerance detection means, a subchannel having a good line quality. It is characterized in that it comprises a scheduling means for controlling to assign a priority to the data burst indicating a low resistance.

  In a wireless communication apparatus using OFDMA (Orthogonal Frequency Division Multiple Access) according to the present invention, subchannels with good channel quality are classified into voiced / sound based on the subchannel channel quality information output from the subchannel channel quality measuring means. Even if there is a subchannel with poor channel quality by performing scheduling to control preferential allocation to data bursts where silence information is voiced or transmission error tolerance information is low tolerance, It is possible to maintain the call quality of each subscriber without reducing the number.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is an explanatory diagram showing a BS (base station) wireless communication apparatus according to the first embodiment of the present invention. In FIG. 1, the same parts as those of FIG.

  In FIG. 1, there are only two points of difference from the prior art (FIG. 3) in that the voice detecting means 26 is provided and the processing contents of the scheduling processing unit 24, and therefore only those contents will be described.

  The voice detection means 26 is controlled so as to operate only when the switch 11 is connected to the transmission voice data a1 side. For the input transmission voice data a1, sound (sound is present) / sound (for each frame) The voice / silence information s1 which is the voice detection result in each frame is output to the scheduling processing unit 24.

  FIG. 8 is an explanatory diagram showing a voice detection result in each frame in the first embodiment of the present invention. In FIG. 8, the shaded portion is sounded and the blank portion is silent. That is, as shown in FIG. 8, in frame n, data bursts # 1, 3, 5, 6, 8, 9, 10 are sounded, and data bursts # 2, 4, 7, 11, 12, 13, 14 Is silent. In frame n + 1, data bursts # 1, 3, 5, 7, 8, 9, and 11 are sounded, and data bursts # 2, 4, 6, 10, 12, 13, and 14 are silent.

  In the subchannel channel quality measurement unit 25 of FIG. 1, the CINR is measured for each subchannel from the received signal r1 for each subchannel output from the OFDMA division processing unit 19, and the scheduling processing unit is used as subchannel channel quality information p1. To 24.

  FIG. 5 is an explanatory diagram showing an OFDMA frame structure for explaining scheduling of frame n according to the first embodiment of the present invention. FIG. 6 shows scheduling of frame n + 1 according to the first embodiment of the present invention. It is explanatory drawing which shows the OFDMA frame structure for demonstrating. That is, the scheduling processing unit 24 in FIG. 1 observes the CINR state in correspondence with the two-dimensional OFDMA frame structure, and determines an arbitrary number of subchannels with good CINR for a long time (in this description, the number of data bursts). = 7, half of 14). In the OFDMA frame structure shown in FIGS. 5 and 6, seven subchannels with good channel quality (high CINR) are indicated by hatching in frames n and n + 1. Further, it is assumed that the sound / silence information s1 that is the output from the sound detection means 26 in the frames n and n + 1 indicates the values in FIG.

  At this time, as shown in the OFDMA frame structure in FIG. 5, the data bursts are allocated to the respective subchannels in subframes with good channel quality (in the shaded area) in the downlink (DL) subframe in frame n. Data bursts # 1, 3, 5, 6, 8, 9, and 10 in which the voice detection results indicate sound are assigned to s + 2, s + 3, s + 4, s + 5, s + 9, s + 10, and s + 13, and the line quality is poor ( Data bursts # 2, 4, 7, 11, 12, 13, and 14 whose sound detection results indicate silence are assigned to the subchannels s, s + 1, s + 6, s + 7, s + 8, s + 12, s + 14, and s + 15 (blank portions). Further, in the uplink (UL) subframe, data burst # 2, in which the voice detection result indicates silence in subchannels s + 2, s + 3, s + 4, s + 5, s + 9, s + 10, and s + 13 with good channel quality (shaded area). 4, 7, 11, 12, 13, and 14 are assigned, and the voice detection results are sounded in subchannels s, s + 1, s + 6, s + 7, s + 8, s + 12, s + 14, and s + 15 having poor channel quality (blank portions). Data bursts # 1, 3, 5, 6, 8, 9, and 10 shown are assigned.

  The reason will be described. Since the voice data whose voice is detected by the voice detection means 26 is data in the downlink direction, the voice detection result indicates that there is a voice and the data burst is assigned to the subchannel with good channel quality. Therefore, since a frame in which voice is present can be transmitted with good line quality, good call quality can be maintained. Frames with no voice are not significantly affected even if the line quality is not good.

  Next, the basis of how to allocate the uplink audio signal will be described. The ratio of the voiced section in the call voice is about 50% of the total, and the probability that the other party is not speaking when you are speaking, and the probability that the other party is speaking when you are not speaking. high. Therefore, since the voice data whose voice is detected by the voice detection means 26 is downlink data, the uplink voice signal is likely to be sounded in a frame in which the downlink data indicates silence. Therefore, it is considered effective to assign a data burst whose sound detection result indicates silence to a subchannel with good channel quality (shaded area).

  FIG. 6 shows a change in the allocation of data bursts to each subchannel when the voice detection result changes in frame n + 1 with respect to frame n (changes in data bursts # 6, 7, 10, and 11). That is, as shown in the OFDMA frame structure of FIG. 6, in the frame n + 1, in the downlink (DL) subframe, the subchannels s + 2, s + 3, s + 4, s + 5, s + 9, s + 10, s + 13 have good channel quality (shaded areas). Are assigned data bursts # 1, 3, 5, 7, 8, 9, and 11 whose voice detection results indicate sound, and subchannels s, s + 1, s + 6, and s + 7 having poor channel quality (blank portions). , S + 8, s + 12, s + 14, and s + 15 are assigned data bursts # 2, 4, 6, 10, 12, 13, and 14 whose sound detection results indicate silence. In the uplink (UL) subframe, data burst # 2, in which the voice detection result indicates silence in subchannels s + 2, s + 3, s + 4, s + 5, s + 9, s + 10, and s + 13 with good channel quality (shaded area). 4, 6, 10, 12, 13, and 14 are assigned, and the voice detection result is sounded in subchannels s, s + 1, s + 6, s + 7, s + 8, s + 12, s + 14, and s + 15 having poor channel quality (blank portions). Data bursts # 1, 3, 5, 7, 8, 9, and 11 shown are assigned.

  In the first embodiment, in order to simplify the description, the number of subchannels with good line quality and the number of data bursts indicating sound are set to the same number (= 7). Sub-channels may be allocated to data bursts indicating the highest in the order of CINR. In this case, in order to maintain fairness, it is also possible to rotate data bursts indicating sound and assign them to sub-channels with high CINR.

  FIG. 2 is an explanatory diagram showing a BS (base station) radio communication apparatus according to the second embodiment of the present invention. 2, the same parts as those in FIG. 3 are denoted by the same reference numerals, and the description thereof is omitted.

  2 differs from the prior art (FIG. 3) only in that it has the transmission error resilience detecting means 27 and the processing contents of the scheduling processing unit 24. To do.

  The transmission error tolerance detecting means 27 is controlled so as to operate only when the switch 11 is connected to the transmission audio data a1 side. Here, the transmission error tolerance information t1 corresponding to the voice coding scheme indicated by the identification code is obtained by adding a voice coding scheme identification code to the transmission voice data a1 to be communicated, thereby performing scheduling processing. To 24. As the transmission error tolerance information t1, for example, when the identification code indicates G.726 (ADPCM), the transmission error tolerance is “low” (calling is possible up to an error rate of about 1e-3), and the identification code is G. When .729 (CS-ACELP) is indicated, the transmission error tolerance is “high” (calling is possible up to an error rate of about 1e-2). In this way, transmission error tolerance differs between the speech coding scheme and the error correction scheme applied thereto (some speech coding schemes do not use an error correction scheme).

  FIG. 9 is an explanatory diagram showing transmission error tolerance information of each data burst in the second embodiment of the present invention. In FIG. 9, the hatched portion has a transmission error resistance of “low”, and the blank portion has a transmission error resistance of “high”. That is, as shown in FIG. 9, transmission error tolerance information t1, which is an output from transmission error tolerance detection means 27 of each data burst in frame n, is data burst # 1, 3, 5, 6, 8, 9, 10 The transmission error tolerance is “low” and the transmission error tolerance is “high” in data bursts # 2, 4, 7, 11, 12, 13, and 14.

  In the subchannel channel quality measurement unit 25 of FIG. 2, CINR is measured for each subchannel from the received signal r1 for each subchannel output from the OFDMA division processing unit 19, and the scheduling processing unit is used as subchannel channel quality information p1. To 24.

  FIG. 7 is an explanatory diagram showing an OFDMA frame structure for explaining scheduling of frame n in the second embodiment of the present invention. That is, in the scheduling processing unit 24 of FIG. 2, the CINR state is observed in correspondence with the two-dimensional OFDMA frame structure, and an arbitrary number of subchannels with good CINR over a long time (in this description, the number of data bursts). = 7, half of 14). In the OFDMA frame structure of FIG. 7, in the frame n, seven subchannels with good channel quality (high CINR) are indicated by hatching.

  At this time, as shown in the OFDMA frame structure in FIG. 7, the data bursts are assigned to the respective subchannels in the subchannels s + 2, s + 3, s + 4, s + 5, which have good channel quality (in shaded areas), as shown in the OFDMA frame structure of FIG. Data bursts # 1, 3, 5, 6, 8, 9, and 10 in which transmission error tolerance information indicates “low” are assigned to s + 9, s + 10, and s + 13, and the channel quality is poor (blank portion). Data bursts # 2, 4, 7, 11, 12, 13, and 14 whose transmission error tolerance information indicates “high” are allocated to s, s + 1, s + 6, s + 7, s + 8, s + 12, s + 14, and s + 15. By executing such scheduling, good call quality can be maintained.

  In the second embodiment, in order to simplify the description, the number of subchannels with good channel quality and the number of data bursts with transmission error tolerance information “low” are set to the same number (= 7). In this process, subchannels may be allocated to data bursts whose transmission error resilience information indicates “low” in order of increasing CINR. Further, in this case, in order to maintain fairness, it is conceivable to rotate data bursts whose transmission error tolerance information is “low” and assign them to subchannels with high CINR.

  In the first and second embodiments, the TDD method is used as the duplex method, and the uplink / downlink is realized at the same frequency. Therefore, the subchannel quality of the uplink can be measured. For example, it is assumed that the result can be applied to the downlink as it is.

  Further, the present invention is not limited to the above-described embodiments as they are, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage. Further, various inventions can be formed by appropriately combining a plurality of constituent elements disclosed in the embodiment. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, you may combine suitably the component covering different embodiment.

1 is a configuration explanatory diagram showing a BS (base station) radio communication apparatus according to a first embodiment of the present invention. FIG. FIG. 5 is an explanatory diagram illustrating a BS (base station) radio communication apparatus according to a second embodiment of the present invention. It is structure explanatory drawing which shows one example of the physical layer of the radio | wireless communication apparatus for WiMAX base stations (BS) using the conventional OFDMA. It is explanatory drawing which shows the frame structure of OFDMA. It is explanatory drawing which shows the OFDMA frame structure for demonstrating the scheduling of the frame n which concerns on the 1st Embodiment of this invention. It is explanatory drawing which shows the OFDMA frame structure for demonstrating the scheduling of the frame n + 1 which concerns on the 1st Embodiment of this invention. It is explanatory drawing which shows the OFDMA frame structure for demonstrating the scheduling of the frame n in the 2nd Embodiment of this invention. It is explanatory drawing which shows the audio | voice detection result in each frame in the 1st Embodiment of this invention. It is explanatory drawing which shows the transmission error tolerance information of each data burst in the 2nd Embodiment of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 11 ... Switch, 12 ... Randomization process part, 13 ... Error correction encoding process part, 14 ... Bit interleave process part, 15 ... Modulation mapping process part, 16 ... OFDMA multiplexing process part, 17 ... Transmission RF part, 18 REFERENCE RF unit, 19 OFDMA division processing unit, 20 DEMODULATION demapping processing unit, 21 BIT DEINTERLETION processing unit, 22 ERROR CORRECTION decoding processing unit, 23 Randomization restoration processing unit, 24 SCANNING processing unit, 25 ... subchannel line quality measuring unit, 26 ... voice detecting means, 27 ... transmission error tolerance detecting means.

Claims (2)

OFDMA (Orthogonal Frequency Division Multiple Access) is used as a multiple access method, and has a two-dimensional frame structure in which one axis is an OFDMA symbol number and the other axis is a subchannel number, and is used for data burst of voice signals. A wireless communication device that performs subchannel allocation in the time domain,
Voice detection means for determining whether the input voice data is voiced or silent, and outputting voiced / silent information;
Data burst generating means for generating a data burst from the input voice data;
Subchannel line quality measuring means for measuring the channel quality of each subchannel;
Based on the subchannel line quality information that is output from the subchannel line quality measuring means, a subchannel with good line quality is converted into a data burst in which the voice / silence information that is output from the voice detecting means indicates voice. A wireless communication apparatus comprising: a scheduling unit that performs control so as to be preferentially assigned. OFDMA (Orthogonal Frequency Division Multiple Access) is used as a multiple access method, and has a two-dimensional frame structure in which one axis is an OFDMA symbol number and the other axis is a subchannel number, and is used for data burst of voice signals. A wireless communication device that performs subchannel allocation in the time domain,
Transmission error tolerance detection means for detecting the type of voice encoding method of input voice data and outputting transmission error tolerance information;
Data burst generating means for generating a data burst from the input voice data;
Subchannel line quality measuring means for measuring the channel quality of each subchannel;
Based on the subchannel channel quality information output from the subchannel channel quality measurement means, a data burst indicating that the transmission error tolerance information output from the transmission error tolerance detection means indicates a low tolerance for a subchannel with good channel quality. And a scheduling means for controlling to preferentially assign to the wireless communication apparatus.

Images