Towards versatile access networks (Chapter 3)

Compared to its previous generations, the 5th generation (5G) cellular network features an additional type of densification, i.e., a large number of active antennas per access point (AP) can be deployed. This technique is known as massive multipleinput multiple-output (mMIMO) [1]. Meanwhile, multiple-input multiple-output (MIMO) evolution, e.g., in channel state information (CSI) enhancement, and also on the study of a larger number of orthogonal demodulation reference signal (DMRS) ports for MU-MIMO, was one of the Release 18 of 3rd generation partnership project (3GPP Rel-18) work item. This release (3GPP Rel-18) package approval, in the fourth quarter of 2021, marked the start of the 5G Advanced evolution in 3GPP. The other items in 3GPP Rel-18 are to study and add functionality in the areas of network energy savings, coverage, mobility support, multicast broadcast services, and positionin

Architecture landscape

The network architecture evolution journey will carry on in the years ahead, driving a large scale adoption of 5th Generation (5G) and 5G-Advanced use cases with significantly decreased deployment and operational costs, and enabling new and innovative use-case-driven solutions towards 6th Generation (6G) with higher economic and societal values. The goal of this chapter, thus, is to present the envisioned societal impact, use cases and the End-to-End (E2E) 6G architecture. The E2E 6G architecture includes summarization of the various technical enablers as well as the system and functional views of the architecture

Combined Coding and Spreading in CDMA Systems using Maximum Free Distance Convolutional Codes

In CDMA systems maximum theoretical performance can be obtained by spreading with low-rate error control codes. Previously, orthogonal and superorthogonal codes have been proposed for this purpose. We present in this paper a family of rate-compatible low-rate convolutional codes with maximum free distance. The performance of these codes for spectrum spreading in a CDMA system is evaluated and shown to outperform that of orthogonal and superorthogonal codes as well as conventional coding/spreading schemes. We also show that our low-rate codes will give simple encoder and decoder implementation. With these codes any 1=n rate can be obtained regardless of the constraint length, resulting in a more flexible and powerful scheme than those proposed up to now. Keywords--- CDMA, low-rate convolutional codes, orthogonal codes, superorthogonal codes, rate-compatible, maximum free distance. I. Introduction S PREAD spectrum systems have been used for decades as a way of achieving robustness aga..

Combined Coding and Spreading in CDMA Systems using Maximum Free Distance Convolutional Codes

In CDMA systems maximum theoretical performance can be obtained by spreading with low-rate error control codes. Previously, orthogonal and superorthogonal codes have been proposed for this purpose. We present in this paper a family of rate-compatible low-rate convolutional codes with maximum free distance. The performance of these codes for spectrum spreading in a CDMA system is evaluated and shown to outperform that of orthogonal and superorthogonal codes as well as conventional coding/spreading schemes. We also show that our low-rate codes will give simple encoder and decoder implementation. With these codes any 1=n rate can be obtained regardless of the constraint length, resulting in a more flexible and powerful scheme than those proposed up to now. Keywords--- CDMA, low-rate convolutional codes, orthogonal codes, superorthogonal codes, rate-compatible, maximum free distance. I. Introduction S PREAD spectrum systems have been used for decades as a way of achieving robustness aga..

Evaluation of Coded CDMA with Interference Cancellation

The performance of an asynchronous CDMA system (up-link) employing very low-rate maximum free distance codes for combined coding and spreading is analyzed when successive or parallel interference cancellation is applied. An analytical approach to the evaluation of the bit error rate is presented and shown to give results close to simulations. Our results show that the code-spread system outperforms the conventionally coded and spread system. Without interference cancellation the single-user bound is never reached (except for one user). With two stages of parallel interference cancellation, a code-spread system with a load only slightly less than 1 bit/chip can obtain a bit error rate very close to that of a single-user system. Keywords--- CDMA, low-rate convolutional codes, orthogonal codes, successive interference cancellation, parallel interference cancellation, rate-compatible, maximum free distance. I. Introduction D IRECT-sequence code-division multiple-access (DSCDMA) is the ..

Code-Spread CDMA using Low-Rate Convolutional Codes

In CDMA systems maximum theoretical performance can be obtained by spreading with low-rate error control codes. Previously, orthogonal and superorthogonal codes have been proposed for this purpose. We present in this paper a family of rate-compatible lowrate convolutional codes with maximum free distance. The performance of these codes for spectrum spreading in a CDMA system is evaluated and shown to outperform that of orthogonal and superorthogonal codes as well as conventional coding/spreading schemes. We also show that our low-rate codes will give simple encoder and decoder implementation. With these codes any 1=n rate can be obtained regardless of the constraint length, resulting in a more flexible and powerful scheme than those proposed up to now. Keywords--- CDMA, low-rate convolutional codes, orthogonal codes, superorthogonal codes, rate-compatible, maximum free distance. I. Introduction S PREAD spectrum systems have been used for decades as a way of achieving robustness agai..

Convolutional Codes for Variable Rate, Unequal Error Protection, and Packet Data Services

A flexible and low-complexity variable rate coding scheme based on rate-compatible convolutional codes is presented. The codes have a wide range of code rates and are optimized for good performance on both AWGN and Rayleigh fading channels. Furthermore, the application of these codes for rate matching, combined coding and spreading in a DS-CDMA system and hybrid type-II ARQ schemes are demonstrated. Very long constraint length convolutional codes with sequential decoding is proposed and shown to be a coding scheme suitable for high performance services in wireless systems. Keywords--- variable code rates, rate-compatible convolutional (RCC) codes, rate matching, combined coding and spreading, DS-CDMA, packet data, hybrid ARQ, sequential decoding, fading channels. I. Introduction S INCE the introduction of cellular telephony in the early 80's, virtually all markets and operators have seen a rapid increase in the number of subscribers. In the early 90's the first generation analog syst..

Convolutional Coding and ARQ Schemes for Wireless Communications

Flexible and low-complexity variable rate coding schemes based on rate-compatible convolutional codes are presented. The codes have a wide range of code rates and are optimized for good performance on both AWGN and Rayleigh fading channels. Furthermore, the application of these codes for rate matching, combined coding and spreading in a DS-CDMA system and hybrid type-II ARQ schemes are demonstrated. Very long constraint length convolutional codes with sequential decoding is proposed and shown to be suitable for high performance services in wireless systems. 1 Introduction Since the introduction of cellular telephony in the early 80's, virtually all markets and operators have seen a rapid increase in the number of subscribers. In the early 90's the first generation analog systems were replaced by the second generation digital systems. These systems have higher capacity due to source (speech) coding, channel coding and the inherent robustness of digital transmission. Common for all thes..