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1 Conference Call C Title: R-PDCCH Performance Evaluation Abstract: The performance of R-PDCCH is evaluated in this contribution. In particular, we study different approaches for error detection on R- PDCCH. Simulation results indicate that, for the 7-bit agreed frame format, block coding without provides a more efficient way for error detection than. Therefore, block coding without is recommended for R-PDCCH. Source: Yongbin Wei Peter Gaal QUALCOMM Incorporated QUALCOMM Incorporated ywei@qualcomm.com pgaal@qualcomm.com Joe Odenwalder QUALCOMM Incorporated joeo@qualcomm.com Date: September 30, 2003 Recommendation: Discuss and adopt Notice QUALCOMM Incorporated grants a free, irrevocable license to 3GPP2 and its Organization Partners to incorporate text or other copyrightable material contained in the contribution and any modifications thereof in the creation of 3GPP2 publications; to copyright and sell in Organizational Partner s name any Organizational Partner s standards publication even though it may include portions of the contribution; and at the Organization Partner s sole discretion to permit others to reproduce in whole or in part such contributions or the resulting Organizational Partner s standards publication. QUALCOMM Incorporated is also willing to grant licenses under such contributor copyrights to third parties on reasonable, non-discriminatory terms and conditions for purpose of practicing an Organizational Partner s standard which incorporates this contribution. This document has been prepared by QUALCOMM Incorporated to assist the development of specifications by 3GPP2. It is proposed to the Committee as a basis for discussion and is not to be construed as a binding proposal on QUALCOMM Incorporated. QUALCOMM Incorporated specifically reserves the right to amend or modify the material contained herein and nothing herein shall be construed as conferring or offering licenses or rights with respect to any intellectual property of QUALCOMM Incorporated other than provided in the copyright statement above.

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3 1 INTRODUCTION The agreed framework for cdma2000 Rev. D includes a Reverse Packet Data Control Channel (R-PDCCH) to convey control information related to the transmission on the Reverse Packet Data Channel (R-PDCH). There have been some discussions in WG3 on whether error correction is necessary for R-PDCCH and, if necessary, how to set up channel structure to facilitate error detection. Two types of approaches have been proposed for error detection on R-PDCCH. Using to R-PDCCH. Using block code but without on R-PDCCH. Receiver can always find a trade-off between error detection and error correction, as it is well known in coding textbook. The goal of this contribution is to compare different approaches of error detection for R- PDCCH. 2 R-PDCCH CHANNEL STRUCTURES The current agreed R-PDCCH frame format has seven bits per 10ms, including 5-bit for payload plus SPID, 1-bit for MSIB, and 1-bit for SPECIAL_QoS_MODE indication. This section includes three possible channel structures for R-PDCCH. 2.1 code without MSIB (1 Bit/10 ms) 64 W 48 Encoder Packet & Subpacket Information (6 Bits/10 ms) Orthogonal Encoder Sequence Repetition (Factor = 3) Signal Point Mapping Sequence Polarity Change Channel Gain R-PDCCH on Q Channel ( Mcps) 64 Symbols per 10 ms 192 Symbols per 10 ms (19.2 ksps) Figure 2-1. R-PDCCH Structure with Coding. 1

4 2.2 Convolutional code with R-PDCCH Bits (7 Bits/10 ms) Add 6-Bit Frame Quality Indicator Add 8 Encoder Tail Bits Convolutional Encoder R = 1/4, K = 9 Symbol Repetition (Factor = 3) 13 Bits 21 Bits (2.1 kbps) 64 W 48 Symbol Puncture (5 of 21) Interleaver (192 Symbols) Signal Point Mapping R-PDCCH on Q Channel ( Mcps) 252 Symbols 192 Symbols (19.2 ksps) Figure 2-2. R-PDCCH Structure with Approach A13 R-PDCCH Bits (7 Bits/10 ms) Add 9-Bit Frame Quality Indicator Add 8 Encoder Tail Bits Convolutional Encoder R = 1/4, K = 9 Symbol Repetition (Factor = 2) 16 Bits 24 Bits (2.4 kbps) 64 W 48 Interleaver (192 Symbols) Signal Point Mapping R-PDCCH on Q Channel ( Mcps) 192 Symbols (19.2 ksps) Figure 2-3. R-PDCCH Structure with Approach A16 2

5 3 SIMULATION RESULTS 3.1 Simulation Setup In the simulation, we assume the outer-loop power control is disabled. The R-PICH pilot set-point is fixed with the value required by full-rate R-FCH/R-DCCH shown in Table 1. Inner-loop power control is enabled. Table 2 summarizes the other simulation setup. Table 1 Average pilot setpoint required by R-FCH. Channel Model Average Pilot Ecp/Nt (db) AWGN A B C D E Table 2 Simulation Setup Simulation Parameter Value Channel condition Pilot filter for channel estimation Pilot filter for power control Inner Loop PC step size Outer Loop step size A/B/C/D/E 2.5 ms non-causal FIR 1.25ms causal FIR +/- 1 db 0dB Forward Link PC BER 4% In the following simulation, we consider three metrics: of Missed Detection (MD) = P(Receiver declares no valid message A message is transmitted on R-PDCCH). of False Alarm (FA) = P(Receiver declares a valid message No message is transmitted on R-PDCCH). of Undetected Errors (UDE) = P(Receiver declares a valid message but the message is in fact incorrect A message is transmitted on R-PDCCH). However, the focus will be on MD and FA. UDE is very low for both approaches. One figure of UDE is included as an example ( Figure 9). 3.2 Simulation result with block coding For block decoding, the BS performs max likelihood decoding by correlating the received signal with all orthogonal basis vectors. This can be done by using Fast Hadamard 3

6 Transformation (FHT). The MS selects the maximum of the absolute values of the correlator outputs as a tentative decoding decision. In the next step, the BS computes the energy contained in the maximum correlator output divided by the sum of the energies in all other bins, with the latter sum being raised to the power of 1.2. If the ratio is below a threshold, the BS declares a DTX on the PDCCH. Otherwise, the BS declares non-dtx and outputs the index of the maximum correlator output. The sign of the max correlator output indicates the decoded MSIB. The BS can tune the erasure detection capability (equivalent number of bits) by adjusting the energy ratio threshold. Note that if the PDCCH T/P is known, then the decoding algorithm could be further improved by using the received pilot energy estimate in the thresholding decision. Such knowledge was not assumed in the simulation results for the energy detection algorithm. The results are shown in Figure 4, Figure 5, Figure 6, and Figure 7 for R-PDCCH T/P of -4dB, -3dB, -1.5dB and 0dB, respectively. Note that Channel A was not simulated because of lack of time. It is expected based on prior results that the performance of the PDCCH in Channel A is between the performance in Channel C and Channel D. For all other channels, lacking of data points in the figures indicate that the observed frequency of errors was less than 1e-4. Error with PDCCH Energy Detection, -4dB T/P Missed Detection, Ch_A Missed Detection, Ch_B Missed Detection, Ch_C Missed Detection, Ch_D Missed Detection, Ch_E False Alarm, Ch_A False Alarm, Ch_B False Alarm, Ch_C False Alarm, Ch_D False Alarm, Ch_E Threshold Figure 4 Missed Detection and False Alarm for R-PDCCH with T/P = -4dB. 4

7 Error with PDCCH Energy Detection, -3dB T/P Missed Detection, Ch_A Missed Detection, Ch_B Missed Detection, Ch_C Missed Detection, Ch_D Missed Detection, Ch_E False Alarm, Ch_A False Alarm, Ch_B False Alarm, Ch_C False Alarm, Ch_D False Alarm, Ch_E 1.00E Threshold Figure 5 Missed Detection and False Alarm for R-PDCCH with T/P = -3dB. Error with PDCCH Energy Detection, -1.5dB T/P Missed Detection, Ch_A Missed Detection, Ch_B Missed Detection, Ch_C Missed Detection, Ch_D Missed Detection, Ch_E False Alarm, Ch_A False Alarm, Ch_B False Alarm, Ch_C False Alarm, Ch_D False Alarm, Ch_E 1.00E Threshold Figure 6 Missed Detection and False Alarm for R-PDCCH with T/P = -1.5dB. 5

8 Error with PDCCH Energy Detection, 0dB T/P Missed Detection, Ch_A Missed Detection, Ch_B Missed Detection, Ch_C Missed Detection, Ch_D Missed Detection, Ch_E False Alarm, Ch_A False Alarm, Ch_B False Alarm, Ch_C False Alarm, Ch_D False Alarm, Ch_E 1.00E Threshold Figure 7 Missed Detection and False Alarm for R-PDCCH with T/P = 0dB. 3.3 Simulation result with A13 design A13 Approach (6-bit ) 1.00E-04 Model A, Missing Detection Model A, False Alarm Model B, Missing Detection Model B, False Alarm Model C, Missing Detection Model C, False Alarm Model D, Missing Detection Model D, False Alarm 1.00E-05 Model E, Missing Detection Model E, False Alarm T/P (db) Figure 8 Missed Detection and False Alarm for R-PDCCH A13 Design. 6

9 A13 Approach (6-bit ) Model A, Undetected Errors Model B, Undetected Errors Model C, Undetected Errors Model D, Undetected Errors Model E, Undetected Errors 1.00E E T/P (db) Figure 9 Undetected Errors for R-PDCCH A13 Design. 3.4 Simulation result with A16 design A16 Design (9-bit ) Model A, Missing Detection Model A, False Alarm 1.00E-04 Model B, Missing Detection Model B, False Alarm Model C, Missing Detection Model C, False Alarm Model D, Missing Detection Model D, False Alarm 1.00E-05 Model E, Missing Detection Model E, False Alarm T/P (db) Figure 10 Missed Detection and False Alarm for R-PDCCH A13 Design. 7

10 4 SUMMARY The simulation results are summarized in Table 3. Clearly, block coding approach is more efficient (around 1dB) than approach. Therefore, we recommend that block coding approach be adopted for Rev. D. Table 3 Missed-Detection for Different Channel Models, T/P Ratios, and False-Alarm Criteria. Channel Model T/P = -4dB T/P = -3dB 1.56% FA 0.2% FA 1.56% FA 0.2% FA A 0.69% 1.53% 0.25% 0.58% B 4% 7.08% 7.7% 12.43% 2.08% 4.13% 4.45% 7.05% C 0.9% 1.84% 2.2% 3.36% 0.53% 0.90% 1% 1.66% D 0.16% 0.20% 0.39% 0.45% 0.03% 0.06% 0.12% 0.16% E 0.17% 1.06% 0.86% 2.68% 0.04% 0.28% 0.17% 0.85% Channel Model T/P = -1.5dB T/P = 0dB 1.56% FA 0.2% FA 1.56% FA 0.2% FA A 0.06% 0.12% 0.02% 0.03% B 0.78% 1.5% 1.58% 2.8% 0.36% 0.53% 0.57% 1.13% C 0.18% 0.3% 0.31% 0.5% 0.04% 0.08% 0.12% 0.17% D 0.02% 0.02% 0.07% 0.03% E 0.028% 0.04% 0.09% 1.01E E E E- 05 8