NICT PHY Specification Proposal s2

1 July 2014 IEEE P802.15 -15-0540-00-0008

2 IEEE P802.15 3 Wireless Personal Area Networks

Project IEEE P802.15 Working Group for Wireless Personal Area Networks (WPANs)

Title Random access for CFP

Date July 13th, 2015 Submitted

Source Marco Hernandez, Huan-Bang Li, Igor Dotlić, Ryu Miura (NICT)

Response In response to Call for Contributions to TG8

Abstract

Purpose For discussion in TG8

Notice This document has been prepared to assist the IEEE P802.15. It is offered as a basis for discussion and is not binding on the contributing individual(s) or organization(s). The material in this document is subject to change in form and content after further study. The contributor(s) reserve(s) the right to add, amend or withdraw material contained herein.

Release The contributor acknowledges and accepts that this contribution becomes the property of IEEE and may be made publicly available by P802.15. 5

2Submission Page 1 Hernandez, Li, Dotlic, Miura (NICT) 1 July 2014 IEEE P802.15 -15-0540-00-0008

1Contents

21. Random access procedure for peering in CFP...... 2

32. Random access PHY generation...... 3 4 2.1 Random access preamble...... 3 5 2.2 Baseband signal...... 3 6

11. Random access procedure for peering in CFP

2 Once network synchronization and decoding of discovery RB information are achieved by PDs, such 3PDs may request association or peering to a target PD at any time. Consequently, the random access 4can be requested during the peering period, in which control signals are interchanged in order to 5schedule the intended PDs for transmission. 6

7After discovery, PD2 requests association (peering) to PD1 by a random access procedure as illustrated 8in 1. 9 PD2 PD1

RA request

RA response

RA message

Contention resolution message

ACK 10 11 Figure 1—Random access procedure flow diagram 12 13 14 1) PD2 sends a RAP to PD1 requesting association. The RAP is randomly selected from a 15 pool of orthogonal ZC sequences that belong to the RAP Group supported by PD1. PD1 16 selects randomly the time and frequency indexes of a resource slot over the control 17 channel to transmit the RAP. 18 19 2) PD1 detects the RAP, estimates the radio channel, and composes the RA response (RAR) 20 message. Such RAR comprises timing alignment (round-trip delay), first contention-free 21 resource slot for transmission and temporal link ID. 22 23 3) After successful reception of RAR by PD2 over the time-frequency slot where the RAP 24 was transmitted, PD2 adjust timing and composes RA message (RAM) with the temporal 25 link ID for PD2 identification. As several PDs may use the same RA preamble and 26 consequently transmit the RAM over the same granted ReS that result in contention. 27 28 4) Contention resolution: as only one RA message can be detected over all potential 29 contending PDs, PD1 resolves such possible contention by sending the temporal link ID of 30 the successful RA message detected, plus ReS assignment for data transfer in the 31 contention resolution message (CRM). In case of congestion, PD1 may provide a back off 32 indicator to PD2. If a PD in contention receives the contention resolution message with 33 the right temporal link ID, the PD shall terminate the RA procedure as successful. If a PD 34 in contention does not receive the contention resolution message or receives the wrong 35 temporal link ID, such PD shall terminate RA procedure as failure and may repeat it. 36

22. Random access PHY generation

3After the discovery phase, PDs that intend to establish a communication link with a discovered PD 4request that with a random access preamble. According to the superframe structure in Clause 4, after 5discovery, PDs can transmit in the Peering period for peering with another PD. As such PDs can 6transmit at any moment; a set of orthogonal preambles is required in order to reduce interference from 7competing terminals.

8The random access association preambles are named Random Access Preambles (RAPs). Such RAPs 9are formed with ZC sequences as well. Hence, a pool of orthogonal RAPs is formed A unique RAP is 10assigned to every device in a Group. Such unique RAP is used for fine synchronization and control 11messages (how a communication link is granted or how resources are assigned to PDs). The RAP 12signal structure is illustrated in 2.

CP RAP GI

Tcp Tseq TGI 14

15 Figure 2— Random access preamble structure 16

172.1 Random access preamble

18The random access preambles are generated from cyclic shifts of the Zadoff-Chu sequence defined by 19

 r n (n1)  j 20 N an  e

21where N=197, r=1, and n=0,1,…,N-1. 22 23Different random access preambles are generated with cyclic shift α (positive integer

25bn  a(n )Mod N

272.2 Baseband signal

2Submission Page 3 Hernandez, Li, Dotlic, Miura (NICT)