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`Fundamentals of LTE
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`Arunabha Ghosh - Jun Zhang
`Jeffrey G. Andrews - Rias Muhamed
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`Foreword by Rajiv Larnia
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`Page 1
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`CCE_EXHIBIT 2003
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`
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`Fundamentals of LTE
`
`Arunabha Ghosh
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`Jun Zhang
`
`Jeffrey G. Andrews
`
`Rias Muhamed
`
`PRENTIEE
`HALL
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`Upper Saddle River, NJ 0 Boston 0 Indianapolis 0 San Francisco
`New York 0 Toronto 0 Montreal 0 London 0 Munich 0 Paris 0 Madrid
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`Capetown 0 Sydney 0 Tokyo 0 Singapore 0 Mexico City
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`350
`Chapter 9 I Physical Layer Procedures and Scheduling
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`Table 9.20 The Content of Random Access Response Grant
`Purpose
`Information Type Number of Bits
`Indicates whether PUSCH frequency
`Hopping flat
`1
`hopping is applied in the following step.
`
`Fixed-size resource
`10
`Indicates the assigned radio resource for
`block assignment
`the following transmission.
`
`Truncated
`4
`Determines the modulation and coding
`modulation and
`scheme.
`coding scheme
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`TPC command for
`l
`3
`Adjusts the transit power of PUSCH.
`scheduled PUSCH
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`Adjusts the uplink transmission timing.
`UL delay
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`Used in non—contention—based random
`CQI request
`access procedure to determine whether
`an aperiodic CQI report is included in
`the corresponding PUSCH transmission.
`____/
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`resource use different preambles, different UEs can be identified by the eNode—B and
`there is no collision. However, it is possible that multiple UEs select the same preamble.
`which causes a collision. To resolve the contention for access, the UE that detects
`random access preamble transmits a message containing a terminal identity. If the CE
`is connected to a cell, Cell Radio Network Temporary Identifier (C-RNTI) will be used.
`which is a unique UE ID at the cell level; otherwise, a core network identifier is used. In
`step 3, the H—ARQ protocol is supported to improve the transmission reliability.
`Step 4: Contention Resolution Contention resolution is the key feature of the randon;
`access channel. In this step, the eNode—B transmits the contention—resolution message or.
`the DL—SCH, which contains the identity of the winning UE. The UE that observes a
`match between this identity and the identity transmitted in step 3 declares a success and
`completes its random access procedure. If this UE has not been assigned a C—RNTI, the
`temporary identity is then set as its C—RNTI. The H—ARQ protocol is supported in this
`step, and the UE with successful access will transmit an H—ARQ acknowledgment.
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`9J0 PowerConUplhlUpan
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`With SC—FDMA-based transmission in the LTE uplink, orthogonality between intra—cell
`transmission from multiple UEs is achieved, which removes the intra-cell interference and
`the near—far issue typical of CDMA-based systems such as W—CDMA/HSPA. This leaves
`inter—cell interference as the major cause of interference and performance degradation.
`especially for the cell—edge UEs. In LTE, the power control in the uplink is to control the
`interference caused by UEs to neighboring cells while maintaining the required SINR at
`the serving cell. In this section, we describe the power control scheme for the PUSCH
`transmission in the uplink.
`Conventional power control in the uplink is to achieve the same SINR for different
`UEs at the base station, also known as full compensation, but it suffers low spectral
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`9.10 Power Control in Uplink 351
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`efficiency as the common SINR is limited by the cell~edge UEs. LTE specifies Fractional
`Power Control (FPC) as the open—loop power control scheme, which allows for full or
`partial compensation of path loss and shadowing [7, 9, 14]. FPC allows the UEs with
`higher path loss, i.e., cell—edge UEs, to operate with lower SINR requirements so that
`they generate less interference to other cells, While having a minor impact on the cell-
`interior UEs so that they are able to transmit at higher data rates. Besides open—loop
`power control, there is also a closed-loop power control component, which is to further
`adjust the UE transmission power to optimize the system performance.
`We first describe the FPC scheme, based on which the UE adjusts the transmission
`power according to:
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`P = min{Pmax,10logM + P0 + a - PL} [dBm],
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`(9.11)
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`where Pm” is the maximum UE transmission power, M is the number of assigned PRBs,
`P0 is a parameter that controls the mean received SINR, or is the cell-specific path loss
`compensation factor, and PL is the downlink path loss estimate calculated in the UE.
`Note that the transmit power increases with M, which is to to ensure the same power
`spectral density irrespective of the number of PRBS.
`If we only consider path loss and assume 1010gM + P0 + or - PL 3 Pm”, then the
`received signal power at the eNode—B is
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`BzP—PL:mbyW+%+kw&yPLMEm
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`mm)
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`o If 04 = 1, each UE has a constant received power, which corresponds to full com—
`pensation, or channel inversion.
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`o If oz : 0, each UE has the same transmission power that is independent of the path
`loss, i.e., no power control.
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`0 For 0 < on < 1, it is the PFC, and different UEs will have different Pr, depending
`on their path loss to the serving base station.
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`We see that reducing the value of a mainly decreases the transmission power of cell—
`edge UEs, which have large PLs and- are likely to cause a high level of interference to
`neighboring cells. Therefore, by adjusting the path loss compensation factor oz, we can
`reduce inter-cell interference and improve the spectrum efficiency.
`‘Considering both open—loop and closed-loop components, the UE sets its total trans—
`mission power using the following formula:
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`P : min{Pma$,10logM + P0(j) + a(j) - PL + AMCS + f(A,)} [dBm].
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`(9.13)
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`There are three different PUSCH transmission types, corresponding to j = 0, 1, 2:
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`o For PUSCH (re)transmissions corresponding to a semi—persistent grant, j = 0.
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`o For PUSCH (re)transmissions corresponding to a dynamic scheduled grant, j = 1.
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`o For PUSCH (re)transmissions corresponding to the random access response grant,
`j : 2.
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`352
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`Chapter 9 I Physical Layer Procedures and Scheduling
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`The parameters in (9.13) are described as follows:
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`0 For j : 0 or 1, P0 is composed of the sum of a cell—specific nominal component and
`a UE—specific component, provided by higher layers; for j = 2, P0 is a cell—Specific-
`parameter signalled from higher layers.
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`0 Forj = 0 or 1, a(j) is a 3—bit cell-specific parameter, a(j) E {0,04,05, 06, 0.7.0.5.
`0.9,1}; for j = 2, a(j) = 1.
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`o AMOS is a UE—specific parameter depending on the chosen modulation and coding
`scheme (MCS). A large value of AMOS corresponds to higher coding rate and, or
`higher modulation order.
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`0 A,- is a UE—specific closed-loop correction value included in the PDCCH, which i:
`also referred to as a Transmit Power Control (TPC) command. This is to con;-
`pensate the following effects including power amplifier error, path loss estimatic;
`error, and inter—cell interference level changes.
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`0 The function f is to perform closed-loop power control based on A,. It is ["5
`specific. There are two types of closed-loop power control defined in LTE:
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`e Accumulated: The UE applies an offset based on A,- using the latest frat:-
`mission power value as reference:
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`f(Ai) = f(Ai71) + AiiK-
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`(9.1.;
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`The value of A,- is A,- 6 {—1,0, 1, 3} [dB]. For the FDD mode, K : 4, and :1:
`the TDD mode, the value of K depends on the UL/ DL configuration
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`~ Absolute: The UE adjusts the transmission power with an absolute vain—i
`based on A,:
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`f(A,) = A,_K.
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`(9.1:.
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`For this case, the value of A,- is A,- E {—4, —1, 1, 4} [dB]. For the FDD mode.
`K : 4, and for the TDD mode, the value of K depends on the UL/DL
`configuration
`’
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`A similar power control scheme employing FPO is used for sounding reference signal;;
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`9.11
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`Summary and Conclusions
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`In this chapter, we specified the physical layer procedures that provide services to uppe:
`layers.
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`0 CQI feedback from UEs and channel sounding procedure provide the eNode—B with
`channel quality information for downlink and uplink channels, respectively, which
`are then used per UE scheduling and link adaptation. For CQI feedback, to enable
`frequency-selective scheduling and also to keep the overhead low, various reporting
`modes are supported, including period and aperiodic reporting, with both widebani
`and subband reporting. For MlMO modes, RI and PMI feedback are also reported
`from UEs.
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