Lauro joined Award Solutions in 2008, bringing over ten years of experience in the wireless telecommunication industry working with mobile cellular, broadband and satellite communications. Has a thorough knowledge and understanding of all standardized radio transmission technologies (i.e.: GSM, GPRS, EDGE, WCDMA, HSxPA, HSPA+,IS-95, cdma 1xRTT, 1xEV-DO) and non-standardized technologies (i.e.: Flash OFDM, I-Burst, etc.) as well as and their migration path to 4G and beyond (LTE and WiMAX).
Lauro has co-authored four different telecommunication books, has published 18 international refereed journal papers and over 30 international conference papers, all of them results of research in the wireless telecommunication area. Additionally, has presented over 20 different wireless related courses nationally and internationally to a diverse class of clients. Lauro has a thorough knowledge of mathematical analysis and hands-on experience on wireless and traffic engineering design, including Design, Planning, Performance & Optimization as well as computer simulation of mobile wireless networks. Through research and computer simulation techniques has helped a large base of clients (carriers, vendors, new start up companies) develop optimum technological solutions.
Currently, Lauro is one of the instructors at Award Solutions. His current focus is UMTS, HSPA/HSPA+ and LTE. He is also involved in the development of cutting edge training on optimization courses for LTE operators in the USA.
Lauro holds a Ph.D. in electrical engineering (EE) from King's College London, UK (the University of London), a MSc. In EE. and a B.EE from the National Polytechnic Institute, Mexico, all of them with specialty in telecommunications.
In this blog the capacity of the PUCCH for format 2 is assessed.
The following table shows the PUCCH formats used for channel feedback. The channel feedback could carry channel quality indicator (CQI), Precoding Matrix Indicator (PMI) and Rank Indicator (RI), depending on transmission mode configured for the UE. Code Division Multiplexing and Frequency Division Multiplexing is used to multiplex UE’s on the same RB (more accurately RB-pairs) configured for PUCCH resources.
Format 2 carries CQI, PMI and ACK/NACKs. The multiplexing capacity could be 4, 6 or 12, depending on parameter settings. In this example, for illustrative purposes only, let’s assume that the multiplexing capacity is 4
As explained in the previous blog, CQI-PMI-ConfigIndex determines how often the UE is supposed to report CQI and PMI on the PUCCH. RI-ConfigIndex determines how often the UE is supposed to report RI on the PUCCH.
CQI, PMI and RI are transmitted to the eNodeB in format 2, 2a or 2b in the PUCCH as shown below (the picture below assumes a bandwidth of 10 MHz for the UL and 1 resource block for the PUCCH).
If we assume that CQI-PMI-Configindex is within the range 17 £ ICQI/PMI £ 36, then, the reporting period is 20 sub-frames or 20 ms.
Mapping of cqi-pmi-ConfigIndex to Subframe Periodicity
If we assume that RI-Configindex is within the range 322 £ ICQI/PMI £ 482, then, the rank indicator reporting period is 20 sub-frames*4 or 80 ms.
Mapping of ri-ConfigIndex to Subframe Periodicity
nRBCQI is a parameter that defines the number of resource blocks for CQI periodic reporting (Format 2, 2a or 2b). If we assume its value is 2, then, the number of users than can report CQI periodically in the PUCCH is:
NRBCQI * no. of UE multiplexed per sub-frame *periodicity of CQIreporting
= (2RB)(4 UE/RB)(20) = 160 UE per CQI reporting period.
See picture below. The number of UE per PUCCH can be increased by modifying the following parameters:
a) Increasing NRBCQI (but the PUSCH capacity will decrease)
b) Decreasing the periodicity of CQI reporting (decreasing CQI-PMIConfigIndex) but this might affect our uplink throughput.
c) Increasing the number of UE multiplexed per RB.
It is up to the operator to decide how to play with this values and achieve the goals planned.
Very good explanation
Something I don't agree. Multiplexing Capability(UE/RB) of PUCCH format 2/2a/2b should always be 12 (We don't care mixed PUCCH here). deltaPUCCH-Shift has impact on PUCCH format 1/1a/1b only.(You can find answer from section 5.4 of TS 36.211)
Can you help to doubly check it? Thanks!