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1、 STD*EIA TSBL37-ENGL 2000 m 3234600 0655233 b42 TIA/EIA TELECOMMUNICATIONS SYSTEMS BULLETIN Clarification of DTX Receive Handling in TINEIA-136 TSBl17 MAY 2000 TELECOMMUNICATIONS INDUSTRY ASSOCIATION /- Reprcscnhng the iderommumicitions industry io isaciitioa with the Eleclonic Endusbin AUisnee Elic
2、tronic Industri- Alliance Copyright Telecommunications Industry Association Provided by IHS under license with EIALicensee=IHS Employees/1111111001, User=Wing, Bernie Not for Resale, 03/30/2007 20:08:37 MDTNo reproduction or networking permitted without license from IHS -,-,- STDmEIA TSBLL7-ENGL 200
3、0 3234600 Ob55232 ,567 NOTICE TIA/EIA Engineering Standards and Publications are designed to serve the public interest through eliminating misunderstandings between manufacturers and purchasers, facilitating interchangeability and improvement of products, and assisting the purchaser in selecting and
4、 obtaining with minimum delay the proper product for his particular need. Existence of such Standards and Publications shall not in any respect preclude any member or nonmember of T M I A from manufacturing or selling products not conforming to such Standards and Publications, nor shall the existenc
5、e of such Standards and Publications preclude their voluntary use by those other than TIA/EIA members, whether the standard is to be used either domestically or internationally. Standards, Publications and Bulletins are adopted by EIA in accordance with the American National Standards Institute (ANS
6、I) patent policy. By such action, TMEIA does not assume any liability to any patent owner, nor does it assume any obligation whatever to parties adopting the Standard, Publication, or Bulletin. Technical Bulletins are distinguished from TIA/EIA Standards or Interim Standards, in that they contain a
7、compilation of engineering data or information useful to the technical community, and represent approaches to good engineering practices that are suggested by the formulating committee. This Bulletin is not intended to preclude or discourage other approaches that similarly represent good engineering
8、 practice, or that may be acceptable to, or have been accepted by, appropriate bodies. Parties who wish to bring other approaches to the attention of the formulating committee to be considered for inclusion in future revisions of this Bulletin are encouraged to do so. It is the intention of the form
9、ulating committee to revise and update this Bulletin from time to time as may be occasioned by changes in technology, industry practice, or government regulations, or for other appropriate reasons. (From Project No. 4703, formulated under the cognizance of the TIA TR-45.3 Subcommittee on Time Divisi
10、on Digital Technology.) Published by OTELECOMMUNICATIONS INDUSTRY ASSOCIATION 2000 Standards and Technology Department 2500 Wilson Boulevard Arlington, VA 22201 PRICE: Please refer to the current Catalog of ELECTRONIC INDUSTRIES ALLIANCE STANDARDS and ENGINEERING PUBLICATIONS or call Global Engineer
11、ing Documents, USA and Canada (1-800-854-7179) International (303-397-7956) . All rights reserved Printed in U.S.A. Copyright Telecommunications Industry Association Provided by IHS under license with EIALicensee=IHS Employees/1111111001, User=Wing, Bernie Not for Resale, 03/30/2007 20:08:37 MDTNo r
12、eproduction or networking permitted without license from IHS -,-,- STD-EIA TSBLL7-ENGL 2000 3234600 Ob55213 4L5 D TSB-117 Clarification of DTX Receive Handling in TINEIA-1 36 Table of Contents z 1. STATEMENT OF PROBLEM 1 5 2. PROPOSED SOLUTION 1 i Copyright Telecommunications Industry Association Pr
13、ovided by IHS under license with EIALicensee=IHS Employees/1111111001, User=Wing, Bernie Not for Resale, 03/30/2007 20:08:37 MDTNo reproduction or networking permitted without license from IHS -,-,- STD-EIA TSB117-ENGL 2000 3234600 Oh55214 351 H I IO I I I2 13 I4 I5 16 17 18 19 20 21 22 2; 21 25 TSB
14、-117 Clarification of DTX Receive Handling in TINEIA-1 36 1. Statement of Problem Support of the Discontinuous Transmission with Comfort Noise (DTX/CN) feature in TIAEIA- 136-4 1 O and TIAEIA- 136- 133-A may result in potential audio artifacts if the synchronization of the Voice Coder parameter rese
15、t on each side of the air interface is not insured. The potential to encounter unsynchronized Voice Coder parameters may exist if the receive DTX handler relies on the radio channel entering the DTX Low state as the action that initiates the parameter reset. Given the non-deterministic nature of non
16、-speech events detected by the Voice Activity Detector in the mobile station, there is no guarantee that detection of a non-speech event actually results in the radio channel entering the DTX Low state. This may occur if the non-speech event does not persist long enough for the channel to discontinu
17、e transmission, and results in the Comfort Noise Parameter message being immediately followed by speech. It is also recognized that due to radio channel conditions, reception of a transmitted FACCH message is not always guaranteed. The language presented in TIAEIA- 136- 133-A, section 1 and in TIAEI
18、A- 136-4 10, sections 6.4,6.4.1, 6.4.2, and 6.4.3.4, may not clearly identi the appropriate procedural responses to these conditions. The proposed solution rectifies these conditions, by refining the procedural aspects related to support of the DTX/CN feature. The first refinement clearly identifies
19、 receipt of the Comfort Noise Parameter message by the base station as the primary action initiating the Voice Coder parameter reset by the receive DTX Handler. The second refinement provides a DTX Indication to the entity utilizing the channel that the radio channel has entered the DTX Low state. T
20、he receive DTX Handler may use this as an inferred confirmation of the receipt of a Comfort Noise Parameter message, for the purpose of resetting the Voice Coder parameters. 26 2. Proposed Solution 27 28 6.4 Operations on the receive side The changes to TIAlEIA-136-41 O, Sections 6.4, 6.4.1, and 6.4
21、.2 are presented below. 29 30 31 32 side DTX handler. The radio receiver shall determine if the received traffic frame is either a speech frame or CN parameter message frame. It shall also set a bad frame indicator flag to 1 if the he is unusable. Frame information and the bad frame indicator flag a
22、re passed to the receive 33 6.4.1 31 The following text . I escribes the implementation in the bit-exact 35 reference C code. Example solution for classification of speech and CN traffic frames I. 36 37 Regardless of their context (speech, CN parameter message, other FACCH messages or none), the rad
23、io receiver continuously passes the received traffic frames to the receive side 1 Copyright Telecommunications Industry Association Provided by IHS under license with EIALicensee=IHS Employees/1111111001, User=Wing, Bernie Not for Resale, 03/30/2007 20:08:37 MDTNo reproduction or networking permitte
24、d without license from IHS -,-,- 1 2 O 1 : I Invalid combination Good speech frame Valid CN parameter Unusable frame message 5 6 7 8 9 IO II 12 I3 1 1 15 16 17 18 19 20 21 22 23 24 25 26 27 28 i 29 30 31 32 TSB-117 Clarification of DTX Receive Handling in TINEIA-136 DTX handler, individually marked
25、by various preprocessing function with 3 flags. These are the speech frame Bad Frame Indicator (BFI) flag, the CN parameter Bad Frame TSB-117 Clarification of DTX Receive Handling in TINEIA-1 36 The changes to TIA/EIA-136-41 O, Section 6.4.3.4 are presented below. 6.4.3.4 CN synthesis and updating T
26、he CN synthesis procedure uses the speech decoder algorithm with the following modifications: The fixed codebook gain values (see Section 3.1) a x replaced by the random excitation gain value received in the CN parameter message. The fured codebook excitation (see Section 3.1) is replaced by the loc
27、ally genemted random excitation as described in Section 6.4.3.2. The random excitation is filtered by the RESC synthesis filter, as described in Section 6.4.3.3. The adaptive codebook gain value (see Section 3.1) in each subframe is set to O. The pitch delay value (see Section 3.1) in each subframe
28、is set to 60. The LP filter parameters used (see Section 3.1) a t those decoded from the CN parameter message. The predictor memories of the ordinary LP parameter and fixed codebook gain quantization algorithms are reset when SP flag = “O”, so that the quantizers start from their initial states when
29、 the speech activity begins again. If a DTX-Low state indication (see TIAEIA 136-133-A, Section 1.1) is received from a lower layer entity processing the channel and is not pcceded by a valid Comfort Noise parameter message, the predictor memories of the ordinary LP parameter and fixed codebook gain
30、 quantization algorithms shall be reset and a bad franie masking procedure such as that suggested in Section 6.4.4 may be applied. Updating of the CN parameters (random excitation gain, RESC parameters and LP filter parameters) occurs each time a valid CN parameter message is received, as described
31、in Section 6.4.2. When updating the CN, the parameters above should be interpolated over the CN update period to obtain smooth transitions. Spectral dithering should be applied to the interpolated LP parameters prior to using them for CN synthesis. The adaptive tilt factor rn of the tilt compensatio
32、n filter H,(z) (see Section 3.2.1) should be changed to a fixed value o f m = -0.2. With these modifications, the speech decoder now synthesizes comfort noise. . 4 Copyright Telecommunications Industry Association Provided by IHS under license with EIALicensee=IHS Employees/1111111001, User=Wing, Be
33、rnie Not for Resale, 03/30/2007 20:08:37 MDTNo reproduction or networking permitted without license from IHS -,-,- STDoEIA TSBLL7-ENGL 2000 3234600 Ob55218 TT7 I 2 4 5 6 7 8 9 I O I I 12 l i I4 15 16 17 18 19 20 21 22 2: 24 2s 26 27 28 34 35 56 37 28 39 40 41 32 43 TSB-117 Clarification of DTX Recei
34、ve Handling in TINEIA-1 36 The changes to TIA/EIA-133-A are presented below. I Discontinuous-Transmission Discontinuous-Transmission refers to the ability of certain mobile stations to switch autonomously between two transmitter power-level states (DTX-High and DTX-Low). I .I Discontinuous-Transmiss
35、ion on a Digital Traffic Channel In the DTX-High state. the transmitter radiates at a power level indicated by the most recent power-controlling order (Initial Traffic Channel Designation message, Digital Traffic Channel Designation message, Handoff message, Dedicated DTC Handoff message, or Physica
36、l Layer Control message) received by the mobile station. In this state, the mobile station will send CDVCC at all times. BMI support of DTX is indicated in the Handoff, Physical Layer Control, and Dedicated DTC Handoff messages. Mobile Stations on a digital traffic channel may activate DTX with Trun
37、cated Bursts, or DTX without Truncated Bursts if BMI support is indicated by a DTX Mode Information Element. When DTX is activated by a DTX Mode Information Element, the Comfort Noise feature shall be activated also. The base station may provide a DTX Indication to the higher layer entity utilizing
38、the radio channel for each slot that DTX is active. Mobile Stations that do not support DTX Mode, or that are not on a digital traffic channel may activate DTX if BMI support is indicated by a DTX Allowed Information Element. A Mobile Station that activated DTX as a result of receiving a DTX Allowed
39、 Information Element shall not activate the Comfort Noise feature. When DTX without Truncated Bursts is activated in the mobile station, in the DTX-Low state, the transmitter will remain off and the CDVCC will not be sent except for the transmission of FACCH messages. When DTX without Truncated Burs
40、ts is activated in the mobile station, all SACCH messages to be transmitted by the mobile station while in the DTX-Low state shall be sent as FACCH messages after which the transmitter will return to the off state unless Discontinuous-Transmission has been otherwise inhibited. I When DTX without Tru
41、ncated Bursts is activated in the mobile station, and a mobile station desires to switch from the DTX-High state to the DTX-Low state. it may complete all in-progress SACCH messages in the DTX-High state, or terminate SACCH message transmission and resend the interrupted SACCH messages, in their ent
42、irety, as FACCH messages. When DTX with Truncated Bursts is activated in the mobile station, while in the DTX Low state, the mobile station transmitter will remain on during transmission of the DTX Low Truncated Bursts. On a full or half rate digital traffic channel, a truncated burst will be transm
43、itted in every assigned slot while in the DTX Low state. On a double rate, triple rate or multi-rate digital traffic channel, the mobile station will transmit a DTX Low truncated burst in every assigned slot in which it transmits a layer 1 SACCH field while in the DTX High state. Prior to a mobile s
44、tation in the DTX High state switching to the DTX Low state, a Comfort Noise message and all other pending FACCH messages shall be entirely transmitted. The final full length burst prior to transition from the DTX High state to Copyright Telecommunications Industry Association Provided by IHS under
45、license with EIALicensee=IHS Employees/1111111001, User=Wing, Bernie Not for Resale, 03/30/2007 20:08:37 MDTNo reproduction or networking permitted without license from IHS -,-,- 8 9 STDUEIA TSBZL7-ENGL 2000 3234600 Ob552L9 933 W TSB-117 Clarification of DTX Receive Handling in TINEIA-1 36 the DTX L
46、ow state shall include a FACCH message, interleaved with a FACCH Word containing 6 FACCH Filler Octets. Note that while a Comfort Noise Parameter message shall always precede the transition to the DTX Low state, it does not guarantee that the transition to the DTX Low state shall occur. The initial
47、full length burst after transition from the DTX Low to the DTX High state shall include a FACCH Word containing 6 FACCH Filler Octets interleaved with a FACCH message or voice. Note that only one half of the word containing FACCH Filler is transmitted with the final and initial full length bursts. 6 Copyright Telecommunications Industry Association Provided by IHS under license with EIALicensee=IHS Employees/1111111001, User=Wing, Bernie Not for Resale, 03/30/2007 20:08:37 MDTNo reproduction or networking permitted without license from IHS -,-,-
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